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MIKE SHE USER MANUAL VOLUME 2: REFERENCE

1. f 0 5 f 0 5 KI 0 04 1 d 0 8 KI K1 0 04 1 9 1 0 MIKE SHE CXTFIT 0 8 0 6 0 4 0 2 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Days Days Figure 20 6 Kinetic sorption Effects of rate constant K1 d in Eq 20 10 Input to CXTFIT f fraction of equilibrium sorption sites Ky 0 5 ml g Input to MIKE SHE Kd f K CXTFIT At f 1 the function is reduced to equilibrium sorption with Kg 0 5 ml g 362 MIKE SHE User s Guide Process verification LA c c0 Relative concentration Fraction of mass recovery B 0 16 1 d i B 0 16 1 0 0 8 0 6 0 4 0 2 7 B 0 04 1 4 B 0 04 1 4 B 0 02 1 4 B 0 02 1 d MIKE SHE CXTFIT 9 5 0 5 2 35 30 Days Figure 20 7 Conservative solute transport in dual porosity systems Mobile porosity 0 25 immobile porosity 0 05 Effect of mass transfer coefficient Bs in Eq 19 16 d Technical Reference for Water Quality 363 a oe Reactive Transport Reference cO Relative concentration 10 15 Days Figure 20 8 Verification of reactive solute transport in dual porosity systems Mobile porosity 0 25 immobile porosity 0 05 Effect of distribu tion of sorption sites between mobile and immobile regions pma Pp Eq 47 Kd 0 5 ml g mass transfer coefficient B 0 08 a 364 MIKE SHE User s Guide Process verification LAA Relative concentration B 0 16 1 d
2. 234 14 2 1 Aquifer Only Conductance 234 14 2 2 River bed only conductance 235 14 2 3 Both aquifer and river bed conductance 237 14 2 4 Steady state groundwater simulations 238 14 3 Area Inundation using Flood Codes areal source sink 239 14 3 1 Determination of the Flooded Area and Water Levels 239 14 3 2 Calculation of the Exchange Flows 239 14 4 Direct Overbank Spilling to and from MIKE 11 240 10 MIKE Zero 15 EVAPOTRANSPIRATION REFERENCE 243 15 1 Kristensen and Jensen method 244 15 1 1 Sublimation from Snow 64 4 thw wo te a hw ah ote eee 244 15 1 2 Canopy Interception 004 244 15 1 3 Evaporation fromthe Canopy 245 15 14 Plant Transpiration 2 4 6 aod SoS eee A oS AE ee Se a 246 15 1 5 Soil Evaporation 2 a 4 Gack ub ube grees Oh Oe Ba ee 250 15 1 6 Evapotranspiration Coefficients C1 C2 and C3 251 15 2 Simplified ET for the Two Layer Water Balance Method 254 15 2 1 Sublimation fom Snow 2 00000 255 15 2 2 Canopy Interception 0 0 000 4 255 15 2 3 Soil M ist re o cece ces bares OEE Oe be be SH 256 15 2 4 Infiltration ooa 258 15 2 5 Evapotranspiration 2204 dee Owed Beek a 258 15 2 6 Recharge to the Saturated Zone 260
3. 366 21 PARTICLE TRACKING REFERENCE 2 369 21 1 Governing equations 2 ead he deh ehddbe debe db headedes 369 References 6 4 4 44 6 Sew BER be OK oe Gen Bw Vw Sw he Bed HE 375 WO a tes os i ee es Reed oe ee a eS WS 381 13 14 MIKE Zero THE MIKE SHE REFERENCE GUIDE 16 MIKE SHE Se 1 REFERENCE GUIDE OVERVIEW The Reference Guide includes detailed descriptions of the tools and dia logues that you are likely to encounter as you develop a MIKE SHE model If you click F1 in any MIKE SHE dialogue you will land in one of the sections of this manual Likewise if you click F1 in any MIKE 11 or other MIKE Zero dialogue you will land in an appropriate section of the on line help The first part of the document follows the general organization of the MIKE SHE user interface These sections are the places you land when you press the F1 key in MIKE SHE and include e the Setup Data Tab V 2 p 19 e the Preprocessed Data Tab V 2 p 145 and e the Results Tab V 2 p 155 This is followed by detailed descriptions of the various MIKE SHE spe cific editors including the Well editor V2 p 167 e the UZ Soil Properties Editor V 2 p 173 e the ET Vegetation Properties Editor V 2 p 177 e the Water Balance Editor V 2 p 185 e the Particle Tracking Editor V 2 p 193 and e the Simple Shape Editor V 2 p 201 In turn this is followed by the MIKE SHE
4. 0 205 Mid Util ae gie a a ae e tes Go ewe ee es a a ee ee i 205 11 3 1 Grid calculator oaoa 000 000084 205 Technical Reference for Water Movement 207 12 WATER MOVEMENT OVERVIEW aaa aaa a 209 13 OVERLAND FLOW REFERENCE 211 13 1 Finite Difference Method anaana aa 211 13 1 1 Diffusive Wave Approximation o oo aa 211 13 1 2 Finite Difference Formulation 214 13 1 3 Successive Over Relaxation SOR Numerical Solution 216 13 1 4 Explict Numerical Solution 217 13 1 5 Boundary conditions 218 13 1 6 Low gradient damping function 218 13 2 Simplified Overland Flow Routing 4 220 13 2 1 Theoretical basis 0 0 0 0 02002 eee 220 13 2 2 Implementation in MIKE SHE 223 13 2 3 Coupling to other processes 0 223 13 2 4 Avoiding the redistribution of ponded water 224 13 2 5 Routing simple overland flow directly tothe river 225 14 CHANNEL FLOW REFERENCE 227 14 1 Coupling of MIKE SHE and MIKE 11 228 14 1 1 MIKE SHE Branches vs MIKE 11 Branches 230 14 1 2 The River Link Cross section 231 14 1 3 Connecting MIKE 11 Water Levels and Flows to MIKE SHE 232 14 2 River Aquifer Exchange line source link
5. 64 MIKE SHE Land Use Se Name This is the name of the crop or vegetation type in the properties file This name must match exactly the name in the properties file When you select the file name using the browse button you can select the vegetation item from a list of available vegetation types found in the file Start Date The vegetation properties file typically contains information on a year or growing season basis starting from Day 1 Thus the Start Date is the calendar date for the beginning of the growing year or growing season If you want to simulate consecutive growing seasons you must re enter the start dates appropriately If data is missing in the time series then the Leaf Area Index and the Root Depth are both assumed to equal zero If the start dates overlap with the growing sea son information in the vegetation database a warning will be issued in the log file that says the crop development was not over yet before the new crop was started MIKE SHE will then start a new crop cycle at the new start date The Vegetation dialogue also includes a button for the Evapotranspiration Parameters Kristensen and Jensen which are global stationary parame ters Evapotranspiration Parameters Kristensen and Jensen Evapotranspiration Parameters Kristensen amp Je Default Evapo Param ETW file parameters replace default C1 403 C2 0 2 C3 120 Cint 10 5 Aroot 10 25 mr mm ok l m C
6. Ar Pin an Ken Cim 19 16 where is the diffusion coefficient Diffusive exchange is included as a distributed source sink term in the basic advection dispersion equation 19 3 Solute Transport in the Unsaturated Zone The Solute Transport in the Unsaturated Zone links the transport in the overland flow and transport in the saturated zone together Solute transport in the unsaturated zone be simulated in both the soil matrix and macropores Solute transport in the soil matrix is described by a 1D unsaturated formulation of the advection dispersion equation which is considerably simpler than the 3D formulation in the saturated zone Although the unsaturated water movement calculations can be lumped together to save computational time solute transport in the unsaturated zone is always calculated in every column The solute transport boundary conditions and initial conditions are specified independent of any column lumping that was done in the water movement simulation 19 3 1 Governing Equations Soil Matrix Transport For unsaturated solute transport in the soil matrix the advection dispersion equation is ae v 2 D amp R By ahd DE R 19 17 where c is the concentration of the solute R is sum of sources and sinks D is the dispersion coefficient and v is the vertical velocity The advective transport is determined by the water flux calculated during a MIKE SHE WM simulation As the water flow is
7. B 0 08 1 4 B 0 04 1 d B 0 02 1 4 0 8 0 6 0 4 0 2 0 0 0 5 10 15 20 25 30 0 5 10 15 20 25 30 Days Days Figure 20 9 Verification of reactive solute transport in dual porosity systems Mobile porosity 0 25 immobile porosity 0 05 Effect of mass transfer coefficient Bs in Eq 19 16 d 1 Kd 0 5 mI Q Pma Pp 0 25 Eq 20 11 Technical Reference for Water Quality 365 a os Reactive Transport Reference c0 Relative concentration Fraction of mass recove 0 10 1 0 T 20 days e T 20 days T 10 days T 10 days T 5 days 0 08 0 8 0 06 0 6 0 04 0 4 0 02 0 2 T 0 days T 0 days MIKE SHE CXTFIT 0 5 10 15 20 25 30 i 0 5 10 15 20 25 30 Days Days Figure 20 10 Verification of the description of first order degradation Effect of half life time T12 A days Eq 20 13 20 4 1 Other Processes Simulation Examples Some of the process descriptions included in MIKE SHE are too complex to be verified against analytical solutions including transport of reactive solutes in the unsaturated zone under different soil hydrological condi tions plant uptake of solutes transport in macropores in the unsaturated 366 MIKE SHE User s Guide Process verification a zone and the influence of temperature and soil moisture content on degra dation processes To illustrate one of these cases plant uptake of solutes is
8. 128 ETA e ae ep ie Fe eae ate ees 260 Overland Flow 82 87 211 Separated Flow 87 Overland Flow Routing 220 Shape Overlays 24 Coupling asec x ear ee Ou ee aos 223 Sheet Application Area 76 Directly tothe river 225 Sheet Pile Module 300 Implementation 223 Simple Shape Editor 201 Theory s22 lt ce0 2 ba s 220 Simplified ET 254 Over relaxation 44 Simplified Macropore Flow 280 Simulation Period 28 P Simulation Specification 26 Paved Runoff Coefficient 68 Simulation Title 28 PCG Steady State Solver 294 Snowmelt Constants 62 Plant Transpiration 246 Soil Evaporation 250 Ponded Water Soil Moisture 256 276 EF aku See ee a 259 Soil Moisture Retention Curve 173 Potential flow Soil Profile Definitions 93 PCG ka puuna poa ee seca a 290 Soil properties potential flow 290 Stayer UZ araci a sa paora go 99 Precipitation 57 Sources and sinks 272 Rale eca ore age tees aa a 58 Spatial resolution 272 Pre conditioned Conjugate Gradient 290 Steady state river water depth 296 Preprocessed Data 145 SIOIAOG breathy oti we Ge ee Ge 292 Properties Editor 173 Storage Coefficient 114 Pumping Wells 129 Storage terms PCG
9. Branch name the Branch name must be a valid branch name in the MIKE 11 model However this is not checked until run time at which point an error message will be generated if it is not valid and the simu lation will be stopped Chainage like the branch name the chainage must be a valid MIKE 11 chainage UseObsData This is a flag to specify whether or not an observation file needs to be input 0 No 1 Yes dfsOfile name This is the file name of the dfsO time series file with observation data The path to the dfsO file must be relative to the direc tory containing the MIKE SHE she document The dfsO extension is added to the file name automatically and should be not be included in the file name For example Time Calibration RiverstageObs refers to the file RiverStageObs dfs0 located in the subdirectory Time Calibration which is found in the same directory as the she model document dfsOItemNumber This is the Item number of the observation data in the specified DFSO file 142 MIKE SHE Storing of Results oa The following is a simple example with three MIKE 11 observation points where the file name is obsdata dfsO Obs_1 gt gt GrandRiver gt 34500 gt 0 gt time obsdata gt 1 Obs_2 gt gt GrandRiver gt 22500 gt 1 gt time obsdata gt 2 Obs_3 gt gt GrandRiver gt 1500 gt 1 gt time obsdata gt 3 Related Items e Time Step Control V 2 p 30 Detailed time series o
10. If Savailable 1S larger than or equal to the Field Moisture Deficit then the water content of each of the root zone cells is increased to field capacity Technical Reference for Water Movement 317 a oe Saturated Flow Reference If Savailabie 18 smaller than the Field Moisture Deficit then the water con tent of each of the root zone cells is proportionally increased by ait e S feedback 0 a Pae 0 17 55 After the feedback calculation the amount of baseflow to the river is reduced by the amount of water used to satisfy the Field Moisture Deficit in the unsaturated root zone which is Qyz in Figure 17 10 17 2 8 Coupling to Mike 11 The discharge from the lowest Interflow Reservoir in each subcatchment is distributed evenly over the MIKE 11 river nodes located in the reser voir Likewise the baseflow from the Baseflow Reservoirs is distributed over the same nodes The default distribution can be overridden by speci fying specific MIKE 11 Branches and chainages 17 2 9 Limitations of the Linear Reservoir Method The Linear Reservoir method is a simple method for calculating overall water balances in the saturated zone As such it is unsuitable when a detailed spatial distribution of the water table is required However even given the simplicity of the method the following simplifications and limi tations should be noted e Inthe Linear Reservoir Method the same river links are used for both of the b
11. Location The location is defines whether the source is located on the ground surface Surface or in the saturated or unsaturated zone Sub surface The available source types depend on where the source is located Source Type If the source is located on the ground surface then it can be either a Precipitation source concentration in precipitation water or an Overland source mass on the surface In both cases the solute can infiltration or runoff as lateral overland flow Extent Type The source can cover the entire domain Full domain or only part of the domain Part domain In both cases the actual source strength can very spatially and temporally The Extent is used simply to restrict the source data to a zone smaller than the model domain Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Solute Transport in the Unsaturated Zone V 2 p 340 e Solute Transport in Overland Flow V 2 p 344 131 Se Setup Data Tab 2 17 1 Extent Source Extent Distribution Type Grid codes dfs2 Grid Distribution Create C Work main Products Source MSHE RegTest 4D Karup Maps lense dfs E Edit meter 35000 Undefined 30000 25000 Extent Conditions If source extent is Part Domain dialogue Type Integer Grid Code EUM Data Units Integer Grid Code If the source extent is Part Domain then you can define a local extent for which the larger source fi
12. R az I R z dz 15 7 zl where the numerator is the total amount of water extracted in layer i bounded above by Z and below by Z and the denominator is the total 248 MIKE SHE Kristensen and Jensen method a oe amount of water extracted by the roots between the ground surface and the maximum root depth Lp AROOT How the water extraction is distributed with depth depends on the AROOT parameter Figure 15 4 shows the distribution of transpiration for different values of AROOT assuming that the transpiration is at the potential rate with no interception loss C 0 and no soil evaporation loss C7 0 The figure shows that the root distribution and the subsequent transpiration becomes more uniformly distributed as AROOT approaches 0 During simulations the total actual transpiration tends to become smaller for higher values of AROOT because most of the water is drawn from the upper layer which subsequently dries out faster The actual transpiration therefore becomes more dependent on the ability of the soil to conduct water upwards capillary rise to the layers with high root density Figure 15 5 shows the effect of the root depth given the same value of AROOT A shallower root depth will lead to more transpiration from the upper unsaturated zone layers because a larger proportion of the roots will be located in the upper part of the profile However again this may lead to smaller actual transpiration if th
13. model_area shp Lower Left comer Upper Right corner x 578000 m Y 6118000 m x 600500 m 6140500 m meter Untitled 6140000 6138000 6136000 6134000 The simple shape editor is a tool for creating and editing shp file poly gons Polygon shp files can be used in many places in MIKE SHE but the Simple Shape Editor is primarily used for creating and editing single dis crete polygons such as for the model domain However multiple poly gons can be created and edited in the tool At the moment the Simple Shape Editor can be launched directly from only two dialogues the Model Domain and Grid and the Saturated Zone Internal Boundary Conditions If you launch it from one of these two dia logues all of the active background maps will be transferred to and dis played the editor However if you want to change any of the display settings or add or subtract overlays you must exit the editor and make the changes in the Display data item in the Setup Tab It is also possible to launch the editor from the New and Open menu func tions but in this case none of the background maps will be added and you cannot add maps within the tool itself However if you want to use the tool for creating shp file maps for functions outside of the Model Domain and Internal Boundary Conditions then you can still do this by using the New function on one of these dialogues and then creating and editing the polygon norm
14. 2 47 2 3 3 Water Quality Time Step Control 49 2A SPECIES 24 do eae wy ee cod amp ao a be ek OES Hed oo oe 50 2 5 Species Parameters 0 0000 cee ee ee ee eee 51 2 6 Model Domain and Grid aaa aaa 52 2 7 Subcatchments Bh SAEED Ae KE he hee eS 54 2 7 1 River Links 242 bs wack gabe Bede Mae RRR ES 55 20 Topography eresse arere a bg wood Bae de had be OHS 56 29 Precipitation 402 408 ee ke ante os ace oe ee Hoe Hh Rw Sn eek 57 2 9 1 Precipitation Rate 58 2 9 2 Net Rainfall Fraction 2224 4 45 496 45654 bh wee 59 2 9 3 Infiltration Fraction 2 4466 5 44 85e8h4 Ab eae dee 59 2 9 4 Air Temperature 0 0022s 60 2 9 5 Snowmelt Constants 220008 62 210 Land Use sax dieu ok Ga tote an ee ew Ga he Be ee oe 8 62 2 10 1 Vegetation i 2608 22cbi we Phe ck eee ees 64 2 10 2 Paved Runoff Coefficient 68 2 10 3 Irrigation Command Areas iw www sw we ee 69 2 10 4 Sheet Application Area 0004 76 2 10 5 Irrigation Demand 2 viene a Sle eek Sk a ae ee hE 76 2 10 6 Irrigation Priorities 225 ce be be ee ee eee 78 6 MIKE Zero 2 11 2 12 2 13 2 14 2 15 2 16 Evapotranspiration sass Baie a Soe See ae oe a ae ee 79 2 11 1 Reference Evapotranspiration 79 Rivers and Lakes ok add HRS OOS SER ee ee a SS Be 80 212 1 FOO COES ere aa Siete Bde ee as we ek A ee a 81 2 12 2 Bathymetry 2294 6h
15. If the Unsaturated Flow is selected and the Linear Res ervoir Method for groundwater is selected dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground The groundwater table must be explicitly defined if unsaturated flow is simulated without explicitly simulating groundwater flow The specified groundwater table is used as the lower boundary condition for the unsatu rated model If the Linear Reservoir Method is used for the groundwater simulation the water table is not calculated thus requiring the water table to be explicitly defined However the specified groundwater table is a static variable If you need to relate your unsaturated zone model to a dynamic water table you must include the saturated zone in your model based on the 3D Finite Differ ence Method 101 Se Setup Data Tab Related Items e Saturated Flow Reference V 2 p 289 e Linear Reservoir Method V 2 p 307 2 16 Saturated Zone In MIKE SHE the saturated zone is only one component of an integrated groundwater surface water model The saturated zone interacts with all of the other components overland flow unsaturated flow channel flow and evapotranspiration By comparison MODFLOW only simulates the saturated flow All of the other components are either ignored e g overland flow or are simple boundary conditions for the saturated zone e g evapotranspiration On the other hand there are very few
16. Orc for 0 gt Ovt f 8 ea 15 9 Oy 9 0 for 0 lt Suin 250 MIKE SHE Kristensen and Jensen method a os In the absence of vegetation f LAJ can be set to zero and Exin Eq 15 8 goes to zero This allows us to see how E varies in relation to E for dif ferent values of Thus Eq 15 8 can be simplified to E E AACO 8 f3 0 F 6 ee P which is plotted in Figure 15 6 In the MIKE SHE soil evaporation is restricted to the upper node in the unsaturated zone which generally should be about 10 centimetres deep or less 1 0 A E Figure 15 6 Soil evaporation E in relation to E as a function of in the top layer when f LAI 0 15 1 6 Evapotranspiration Coefficients C Co and C3 The equations for actual transpiration Eq 15 3 and soil evaporation Eq 15 8 contain three empirical coefficients C1 C2 and C3 The coeffi cients C and C are used in the transpiration function f LAI Eq 15 4 C3 is also part of Eq 15 3 but is only found in the soil mois ture function Eq 15 5 C C is plant dependent For agricultural crops and grass C4 has been esti mated to be about 0 3 C influences the ratio soil evaporation to transpira tion This is illustrated in Figure 15 7 For smaller C values the soil evaporation becomes larger relative to transpiration For higher C values Technical Reference for Water Movement 251 Evapotranspiration Refere
17. cation is available If this option is chosen an Integer Grid Code file must be provide with the following grid codes e In grid points where automatic classification should be used the grid code must be 1 e In grid points where computation should be performed for all cells the grid code must be 2 Related Items e Unsaturated Flow Reference V 2 p 261 97 LEA Setup Data Tab e Lumped UZ Calculations V 2 p 281 2 14 5 Specified classification Specified Classification Conditions if Specified classification selected in the main Unsatu rated Zone dialogue dialogue Type Integer Grid Codes EUM Data Units Grid Code Valid values 2 to the number of SZ cells 1 0 1 not valid This is a data file specifying Integer Grid Codes where UZ computations are to be carried out Grid codes range from 2 up to the number of UZ col umns The location of the computational column is specified by a negative code and the simulation results are then transferred to all grids with the an equivalent positive code For example if a grid code holds the value 2 a UZ computation will be carried out for the profile located in that grid Simulation results will sub sequently be transferred to all grid codes with code value 2 An easy way to generate a dfs2 file to be used for specification of UZ computational columns is to let the MIKE SHE setup program generate an automatic classification first and subsequently e
18. e the geological model e the vertical numerical discretisation e the initial conditions and e the boundary conditions In the MIKE SHE GUI the geological model and the vertical discretisa tion are essentially independent while the initial conditions are defined as a property of the numerical layer Similarly subsurface boundary condi tions are defined based on the numerical layers while surface boundary conditions such as wells drains and rivers using MIKE 11 are defined independently of the subsurface numerical layers The use of grid independent geology and boundary conditions provides a great deal of flexibility in the development of the saturated zone model thus the same geological model and many of the boundary conditions can be re used for different model discretisation and different model areas The principle Saturated Zone dialogue for MIKE SHE includes three items 103 Setup Data Tab Pumping wells By default wells are not included but in most applications pumping wells play a major role in the hydrology of the area If wells are included in the model then this must be checked and a new item in the data tree appears where the well database can be defined Subsurface drainage Subsurface drainage is used to limit the amount of groundwater that reaches the ground surface and to route near surface groundwater to local streams and rivers There are a number of drainage options for specifying surface dra
19. exponent n will influence the percolation rate in the soil and thereby influ ence the actual evaporation rate 6 2 3 Van Genuchten and Campbell Burdine methods In addition to the tabulated values parametric functions are available using the Van Genuchten and the Campbell Burdine formulations It is important to note that the data is tabulated internally and stored in the same form as if tabulated data were input The van Genuchten Shape Factor is soil texture dependent with a mini mum allowed value of 4 176 MIKE SHE Vegetation Database Items Se 7 7 1 7 1 1 ET VEGETATION PROPERTIES EDITOR The vegetation editor is used to specify vegetation data for the evapotrans piration and irrigation management modules The vegetation database contains the time varying vegetation characteristics for each type of vege tation that is specified in the model domain The vegetation database is optional and can be used only when the Eva potranspiration ET and Unsaturated Zone components are included in the model Vegetation Database Items The vegetation database is organized around a data tree similar to the setup editor To create a vegetation type in the database and populate with the corresponding data simply add a vegetation item in the main dialogue and then fill out the tables in the dialogues that appear in the data tree under the new vegetation item Specifying Vegetation Properties in a Database Evapo
20. this is the threshold value for the water depth in the well If the water level in the well falls below this depth as measured from the topography the pumping will stop until the water rises above the threshold depth again Max rate This is the maximum extraction rate for the shallow well in each cell If more water is required for irrigation then the next source will be activated Top Bottom of Screen The depth of the top and bottom of the screen is used to define from which numerical layers water can be extracted Pumping will stop if the water table falls below the bottom of the layer that contains the filter bottom Shallow well sources are removed from baseflow Reservoir 1 if the Linear Reservoir groundwater method is used The screen interval is ignored 73 LEA Setup Data Tab Note Shallow wells can be located in cells containing single sources The preprocessor will give a warning for such violations Multiple shallow wells are not allowed in the same command area External Source External source Max rate 0 5 ms In some case the irrigation water can be from outside of the watershed being modelled In this case the only constraint is the maximum amount of water than can be extracted from the source Max rate This is the maximum extraction rate for the source If more water is required for irrigation then the next source will be activated Water Application methods There are three ways to apply
21. 2 Drainage in grid cells with a value of 2 is routed via Drain Codes as specified in the Drain Codes data item Code 3 Drainage in grid cells with a value of 3 is routed to a specified MIKE 11 branch and chainage At the moment this options requires the use of Extra Parameters 128 MIKE SHE Saturated Zone a Code 4 Drainage in grid cells with a value of 4 is routed to a specified MOUSE man hole At the moment this options requires the use of Extra Parameters Related Items e Saturated Zone Drainage V 2 p 298 e Drainage with the SOR Solver V 2 p 306 e Extra Parameters V 2 p 144 e SZ Drainage to Specified MIKE 11 H points VJ p 151 e Using MIKE SHE with MOUSE V 1 p 181 2 16 27 Pumping Wells Filename Create Napa Valley FD DBase Napayalley FuralDomesticPumpage 16 WE Edit V Show well location map meter Pumping Wells 603000 mp fe poe 602500 Aa E RARIS proceccseceees Sd aa yi 602000 4 We WETS oo If pumping wells are active in the model domain then you must specify the name of the well database to include in the model setup Edit The Edit button will open the current Well Database with the current maps and overlays open in the well editor You may get an error in when you open the Well Database if the model has not yet been pre processed or if the model data has changed with out re preprocessing the model This error happens because MIKE
22. 2 Hag F 20 13 where A is the half life of the species Following the work of Boesten and van der Linden 1991 to overcome some of the difficulties in simplifying complex biological and chemical reactions the decay in MIKE SHE is dependent of the soil moisture con tent and soil temperature as z Fy F co Ga EES 20 14 where the F is the water content function given as B Tag Py a 20 15 and where 0 is actual soil moisture 0 is saturated moisture content and B is an empirical constant F is the soil temperature function given as R 0 fort iS Be 2 gT TOFU E Ta AG T o Fy e for T gt 3 C 20 16 Technical Reference for Water Quality 357 Reactive Transport Reference where T is the actual temperature of the soil 7 1s the reference tempera ture at which ueis measured and is a constant depending on T T ep the gas constant and the molar activation For simplicity the soil temperature over depth is calculated as a function of the air temperature by an experimentally derived formula given by Klein 1995 Sort O346 Tos r gt i026 i l 20 17 where T is the mean daily soil temperature from yesterday 7 is the mean daily air temperature and z is depth Note that for large depths this function responds very slowly to variations in air temperature Therefore long simulations may be necessary to achieve the required initial temperature distribution An exa
23. 8 Training Courses 2006 Beijing Demo projects Napa Napa Valley FD TIME Groundwater Calibration 007N005W09Q002M dfs0 i OOF NOOS5 YVO9Q002M Observed VVater levels m 9 9 c OOFNOOSYVO9Q002M m Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May 2002 2002 2002 2002 2002 2002 2002 2002 2002 2002 2003 2003 2003 2003 2003 ME 1 563 MAE 1 89026 RMSE 2 43509 STDres 1 86727 R Correlation 0 702677 R2 Nash_Sutcliffe 0 646564 fal The MIKE SHE Detailed time series tab includes an HTML plot of each point selected in the Detailed time series output V 2 p 138 dialogue The HTML plots are updated during the simulation whenever you enter the view Alternatively you can select the Refresh button to refresh the plot Note that the HTML plot is regenerated every time you enter the view So if you have a lot of plots and a long simulation then the regeneration can take a long time Related Items e Detailed time series output V 2 p 138 e Statistic Calculations V 2 p 161 156 MIKE SHE Gridded Data Results Viewer 4 2 Gridded Data Results Viewer Layer no for Groundwater items ae a precipitation rate Ea rooting depth B leaf area index 5s actual transpiration 10 _ depth of overland water Add XY flow E actual evapotranspiration e actual evaporation from interception HE actual evaporation from ponded water a canopy interception storage ig evapotranspi
24. Catchment defined by Shape File Shape File Unit of x and Y axises meter X Create Catchment size and origin Catchment size and origin iF Cell Size x0 yo NX NY 30 30 250 m 578000 m e1 18000 m Model Domain and Grid dialogue Type Special Integer Grid Codes EUM Data Integer Grid Code Units Valid Values le 35 1 2 Regardless of the components included in your model the first step in your model development is to define the model area On a catchment scale the model boundary is typically a topographic divide a groundwater divide or some combination of the two In general there are no constraints on the definition of the model boundaries However the model boundaries should be chosen carefully keeping in mind the boundary conditions that will be used for both the surface water and groundwater components Any non gridded data such as shp file and xyz ASCII files are interpo lated to the grid defined in this dialogue 52 MIKE SHE Model Domain and Grid LAA The grid defined in this dialogue is the primary grid Other dfs2 gridded data does not have to use the same grid However if another dfs2 file uses a different grid then Real data is interpolated If the two grids are coinci dent that is the cells are the same size and the grids line up then the data is bilinearly interpolated to the Model Grid If the grids are not coincident then the data is treated as if it were p
25. Figure 14 2 this is equal to da lp respectively The horizontal infiltra tion length l is calculated based on the depth of water in the river and the geometry of the triangular river link cross section The infiltration area of the river link closely approximates the infiltration area of natural channels when the river is well connected to the aquifer In this case the majority of the groundwater surface water exchange occurs through the banks of the river and decreases to zero towards the centre of the river However in the case of losing streams separated from the groundwater table by an unsaturated zone the majority of the infiltration occurs vertically and not through the river banks In this case the horizon tal infiltration area may be too small if the MIKE 11 bank elevations are much higher than the river level This can be compensated for by either choosing a lower bank elevation or by increasing the leakage coefficient There are three variations for calculating da Technical Reference for Water Movement 237 Se Channel Flow Reference e Ifthe water table is higher than the river water level da is the saturated aquifer thickness above the bottom of the river bed Note however that da is not limited by the bank elevation of the river cross section which means that if the water table in the cell is above the bank of the river da accounts for overland seepage above the bank of the river e Ifthe water tab
26. If there is sufficient water in the top cell at the start of the time step water content sufficiently above field capacity to satisfy root extraction or if there is sufficient net infiltration to raise the moisture content above the field capacity then the flux through the top cell is calculated based on the hydraulic conductivity which is a function of the moisture content The flux is first calculated based on the moisture content at the start of the time step and an updated moisture content is calculated Then the flux is calcu lated again based on the updated moisture content and another moisture content is calculated The actual flux through the cell is then set to the average of these two fluxes Similarly the actual updated moisture content is set to the average of the two moisture contents This flux is then added the cell below and the calculation repeated down wards for the remaining cells in the column Once the water table is reached the water contents in the cells are rebal anced from the bottom up to ensure that no cell is over saturated The flux out the bottom of the soil column is accumulated over the UZ time steps and added as a source to the saturated zone calculation at the start of the next SZ time step 16 2 2 Initial Conditions The initial water content for each node in the soil column is calculated based on the moisture retention curves for each of the soil types in the soil column However if the calculated
27. LayerME MAE RMSE STDres i I head elevation in 1 97985e 006 570854 2 161 5017 61 5017 62 2307 9 49734 1 saturated zone head elevation in 1 98032e 006 569892 2 113 682 113 682 113 989 8 37141 1 saturated zone head i elevation PSSE R es 1 97639e 006 575988 1 6 69369 16 69369 6 69454 0 106626 1 c 00SN003W06R001M c 005N003W08E001M Similar to the detailed time series output the Run Statistics can be viewed during a simulation Press the Refresh button on the Run Statistics page to update the Run Statistics using the most recent model results during a sim ulation 160 MIKE SHE Run Statistics Se 4 4 1 Shape file output for run statistics A shape file of statistics is also generated when the html document is gen erated The shape file contains all of the information contained in the HTML document and can be used to generate maps of model errors that can be used to evaluate spatial bias The shape file is created in the simula tion directory and is named projectname_Stat shp where SimulationName is the name of the she file for the simulation Note the Run Statistics shape file does not have a projection file associated with it and this file should be created using standard ArcGIS methods The statistics contained in the HTML document and the shape file are cal culated using the same methods used to calculate statistics for the detailed time ser
28. MIKE SHE Importing Data Ss Pump definition data This includes data related to the pump 5 1 1 Importing data from a t0 file FILETYPE DATATYPE VERNO The t0 file format was used for MIKE SHE pumping data in Release 2001 and earlier The t0 file format is an ASCII file format that is outlined in the pre MIKE Zero documentation and will not be described here but below is an example 4 51 530 TEXTLINE Groundwater abstraction NREC DELVAL 10 1E 35 START DATE T 1992 1 1 0 0 END DATE 3 2000 12 31 23 59 UTM XYUNIT ZTYPE 32 2 1 21 555371 6138596 5 22 566637 6127708 PEA 23 561464 6128353 36 24 562873 6128089 42 25 563545 6140116 57 26 559444 6133297 Ars 27 556956 6126975 2 28 566406 6138802 23 29 567366 6137663 4 30 558170 6128655 16 12 555371 6138596 555371 555371 W93 3 566637 6127708 566637 566637 W93 9 561464 6128353 561464 561464 W94 5 562873 6128089 562873 562873 W94 8 563545 6140116 563545 563545 W69 2 559444 6133297 559444 559444 W 3 8 556956 6126975 556956 556956 W74 9 566406 6138802 566406 566406 W 4 10 567366 6137663 567366 567366 W83 6 558170 6128655 558170 558170 We7 9 oan ono nsan 31 23 59 2 27 27 fi 27 27 31 23 59 9 25 9 25 9 25 9 25 9 25 31 23 59 0 23 0 23 0 23 0 23 0 23 31 23 59 6 24 6 24 6 24 6 24 6 24 31 23 59 7 19 7 19 19 19 19 31 23 59 8 19 8 19 8 19 8 19 8 19 31 23 59 0 22 0 22 0 22 0 22 0 22 3i 23 59 0 2 D 27 D 27 0 27
29. SHE is trying to reconcile and plot both the geologic layers input data and the numerical layers preprocessed data for each cell containing a pumping well Create The Create button will create a new Well Database file 129 Setup Data Tab Related Items e Well editor V 2 p 167 e 3D Finite Difference Method V 2 p 289 e Boundary Conditions V 2 p 296 e Linear Reservoir Method V 2 p 307 e Calculation of Baseflow V 2 p 316 2 17 Sources axles Species Location pomes Lect Type Type 4 Agricutture Nitrate Surface Overland Part domain The specification of water quality sources is very flexible The Sources dialogue allows you to add and delete sources as well as define the type and location of the source The table provides an overview of all of your sources in your model An important feature of the source location definition is the partial extent distribution function This allows you to define for example a distributed global source file say of the field scale agricultural inputs in your catch ment and run individual water quality scenarios for each sub catchment modelled as an partial extent to assess the subcatchment contributions to the global stream impact Source Name The name appears in the data tree for reference 130 MIKE SHE Sources Se Species You can only choose from the list of available species that you have defined in the Species V 2 p 50 dialogue
30. Topography dialogue Type Stationary Real Data EUM Data Elevation Units In MIKE SHE the topography defines the upper boundary of the model The topography is used as the top elevation of both the UZ model and the SZ model The topography the defines the drainage surface for overland flow Many of the elevation parameters can be defined relative to the topogra phy such as e Lower Level Geological Layer or Lense or Water Quality Layer V 2 p 111 e Upper Level V 2 p 111 e Lower Level Numerical Layer V 2 p 117 e Initial Potential Head V2 p 117 and e Drain Level V 2 p 125 Depth parameters such as ET Surface Depth V 2 p 100 are also meas ured from the topography Topography is typically defined from a DEM defined from either a point theme shape file or an ASCII file If you have an ArcGIS Grid DEM this can be converted to a dfs2 file using the MIKE Zero Toolbox Surfer Grid files can be saved as an ASCII xyz files and then interpolated in MIKE SHE Non dfs2 files or dfs2 files that have a different grid definition than the model grid are all interpolated to the grid defined in the Model Domain and Grid The bilinear interpolation method is useful for interpolating previously gridded DEM data Whereas the triangularisation method is useful for contour data digitized from a DEM 56 MIKE SHE Precipitation a oe Related Items e Bilinear Interpolation V p 260 e Trian
31. amount of water available for infiltration which is the depth of overland water on the ground surface This is reduced to the saturated conductivity of the first unsaturated soil cell which is the maximum infiltration rate for the soil column Equation 16 26 The infiltration rate is further reduced if a leakage coefficient has been specified for the overland unsaturated zone interface which may be done in paved areas or under lakes A leakage coefficient must be explicitly specified for paved areas that are specified as part of the overland flow routing system That is paved areas may be defined as part of the overland flow module to route water to streams from parking lots etc However any reduction in the leakage coefficient under such paved areas must be explicitly defined in the unsaturated zone module For example in an model cell where 25 of the land area is paved a leakage coefficient may 274 MIKE SHE Two Layer Water Balance on be specified equal to 0 25 times the hydraulic conductivity of the surficial soil If the water table is above the ground surface the infiltration is set to zero In the special case that the water table is above the top node of the soil col umn but below the ground surface the infiltration rate is reduced to an estimate of the moisture deficit in the top cell This is done to reduce or prevent artificial cycling of water between the unsaturated zone and pon ded water on the surface
32. and SZ time steps are only active when the component is selected Variable Dimensions Initial time step hrs Max allowed OL time step hrs Max allowed UZ time step hrs Max allowed SZ time step hrs Increment rate Max precipitation depth per time step mm Max infiltration amount per time step mm Input precipitation rate requiring its own time step mm hr Time Steps Initial time step This is the initial time step for all of the components unless the component s maximum allowed time step is less than the initial time step 30 MIKE SHE Simulation Specification LEA Max allowed time steps Each of the main hydrologic components in MIKE SHE run with independent time steps Although the time step control is automatically controlled whenever possible MIKE SHE will run with the maximum allowed time steps Note In the 2007 Release the MIKE 11 time step is no longer specified in MIKE SHE The component time steps are independent but they must meet to exchange flows which leads to some restrictions on the specification of the maximum allowed time steps If MIKE 11 is running with a constant time step then the Max allowed Overland OL time step must be a multiple of the MIKE 11 constant time step If MIKE 11 is running with a variable time step then the actual OL time step will be truncated to match up with the nearest MIKE 11 time step The Max allowed UZ time step must be an even
33. defines the interception storage capacity of the vegeta tion A typical value is about 0 05 mm but a more exact value may be determined through calibration Note The interception coefficient is a unit of length mm not a rate This means that the full amount is intercepted in every time step if precipita tion is available and the storage is not full Thus the total amount of inter cepted water is time step dependent For example if you have a precipitation rate of 2 mm hour over 12 hours the total precipitation will be 24 mm However the total interception could range between 2 mm if the time step length is 12 hours to the full 24 mm if the time step length is 1 hour assuming that there is 2 mm of evapotranspiration per time step 15 1 3 Evaporation from the Canopy The evaporation from the canopy storage is equal to the potential evapo transpiration if sufficient water has been intercepted on the leaves that is E an mind can max E At where Esan is the canopy evaporation LT E is the potential evapotrans piration rate LT and At is the time step length for the simulation Note The amount of evaporation from the canopy is time dependent since the interception on the canopy is calculated for every time step So if you half the time step then the total amount of water stored in the can opy will double The total amount of water stored in the canopy in temper ate climates is generally small compared to th
34. used to calculate the Ky values K fK 20 3 oc where fpe is the fraction of organic carbon By substituting Eq 20 3 into Eq 20 2 neglecting the decay term and reorganising the terms af o a a a amp 2 a Ka F evi 5 o gt 20 4 352 MIKE SHE User s Guide Sorption Ss Sorbed concentration Sorbed concentration Commonly referred to is the retardation factor R which is the ratio between the average water flow velocity v and the average velocity of the solute plume c The retardation factor is calculated as v R i Ke Ve 20 5 The Freundlich sorption isotherm is a more general equilibrium isotherm which can describe a non linear relationship between the amount of solute sorbed onto the soil material and the aqueous concentration of the solute 7 N c Kye 20 6 where K and N are constants The relationship between K and N is shown in Figure 20 1 0 02 0 4 0 6 08 4 1 2 14 16 18 2 Liquid concentration Figure 20 1 Illustration of the Freundlich isotherm a effect of change in N b effect of change in Kf Both the linear and the Freundlich isotherm suffer from the same funda mental problem That is there is no upper limit to the amount of solute Technical Reference for Water Quality 353 LAA Reactive Transport Reference that can be sorbed In natural systems there is a finite number of sorption sites on the soil material and consequently an upper
35. 0 C and hence that precipita tion does not occur as snow In this section the theory and principles behind the Kristensen and Jensen 1975 evapotranspiration model are presented in detail 15 1 1 Sublimation from Snow If the air temperature is below the Threshold melting temperature then the water will be removed from the snow storage as sublimation before any other ET is removed using Esnow Reference_ET At 15 1 where Reference_ET refers to the Reference Evapotranspiration V 2 p 79 before being reduce by the Crop Coefficient ke that is speci fied in the Vegetation Development Table V 2 p 180 If there is not enough snow storage then E now will reduce the snow storage to zero 15 1 2 Canopy Interception Interception is defined as the process whereby precipitation is retained on the leaves branches and stems of vegetation This intercepted water evap orates directly without adding to the moisture storage in the soil MIKE SHE Kristensen and Jensen method a oe The interception process is modelled as an interception storage which must be filled before stem flow to the ground surface takes place The size of the interception storage capacity Lmax depends on the vegetation type and its stage of development which is characterised by the leaf area index LAI Thus I C max LAI 15 2 int where C is an interception coefficient L and LAJ is leaf area index The coefficient C
36. 1 then the first option above is used Ifthe grid code equals 2 then the second method above is used Ifthe grid code equals 3 then the drainage can be routed directly to a particular MIKE 11 branch Ifthe grid code equals 4 then the drainage can be routed to a partic ular MOUSE manhole Drain not routed but removed from model The fourth option simply exports drainage water out of the model Related Items e Time varying drainage parameters V p 154 e Saturated Zone Drainage V 2 p 298 e Drainage with the SOR Solver V 2 p 306 e SZ Drainage to Specified MIKE 11 H points VJ p 151 e Using MIKE SHE with MOUSE V 1 p 181 2 16 23 Drain Level Drain Level dialogue Type Stationary Real Data EUM Data Units Elevation If surface drainage is routed by drain levels the drainage routing reference system is created automatically using the slope of the drains calculated from the drainage levels in each cell see Drain flow determined by level of drain This option was originally the only option in MIKE SHE The ref 125 Setup Data Tab erence system is created automatically using the slope of the drains calcu lated from the drainage levels in each cell Thus as long as a downward slope is found the drain flow will continue until crossing a river or the model boundary If surface drainage is routed by grid codes the drain levels are used to cal culate the amount of drain flow produc
37. 16 UNSATURATED FLOW REFERENCE 261 16 1 Richards Equation aoaaa aa a 262 16 1 1 Numerical Solution aoaaa a 263 16 1 2 Boundary Conditions 2 4 56 i004 64 a 268 16 1 3 Initial Conditions 2 oaoa a 271 16 1 4 Sources and sinkS aoaaa aa a 272 16 4 5 Spatial resolut ie 4 44 ea ani a Sw adh a ee ee A 272 16 2 Gravity Flow aaa aaa Cee SO de Oe Belk eee Oe 273 16 2 1 Solution method 0 0 000 274 16 2 2 Initial Conditions fe he 6 ad eH em ak ek ee eH eee 275 16 3 Two Layer Water Balance 275 1623 1 Soil MoisStUre 5 ses 0 t G ate ot are Sy we ew ee Se ROS E 276 16 3 2 Infiltration 2 2 2 2 2 2 2 2 2 2 2 002 2 2 00 279 16 4 Simplified Macropore Flow bypass flow 280 16 5 Lumped UZ Calculations 0 00000504 281 16 6 Coupling the Unsaturated Zone to the Saturated Zone 282 16 6 1 Steps inthe Coupling Procedure 284 16 6 2 Limitations 2 00 287 16 6 3 Evaluation of the UZ SZ Coupling 287 17 SATURATED FLOW REFERENGE 4 24 2004545404684 060 48 44 4 289 17 1 3D Finite Difference Method 289 17 1 1 The Pre conditioned Conjugate Gradient PCG Solver 290 17 1 2 PCG Steady State Solver 294 17 1 3 Boundary Conditions s os0d Beet Pee hha GS RHE oR 296 17 1 4 Initial Conditions acca hk we
38. 2 4 Source Sinks Boundary Conditions and other Exchanges 338 19 2 5 Transport in Fractured Media 339 19 3 Solute Transport in the Unsaturated Zone 340 19 3 1 Governing Equations 200 340 19 3 2 Solution Scheme s sese sri acy id Grow es er 4 awd 341 19 3 3 Initial Conditions as oiu Bieve dcg doe Reels eo Roe Sees Ko SO 343 19 3 4 Source Sinks Boundary Conditions and other Exchanges 343 19 4 Solute Transport in Overland Flow 0 344 19 4 1 Governing Equations 200 4 345 19 4 2 Solution scheme 4 e4 64 2 Gove Hh de eee Ga exe 345 19 4 3 Initial Conditions ek ew Bae ee Re Ok wR we Ke 347 19 4 4 Source Sinks Boundary Conditions and other Exchanges 348 19 5 Solute Transport in MIKE 11 000 4 348 20 REACTIVE TRANSPORT REFERENCE 351 20 1 Sorption aces 4 024 4 axle ethan 2 Gud bao eared Oaks aw eee 351 20 1 1 Equilibrium Sorption Isotherms 352 20 1 2 Kinetic Sorption lsotherms 355 20 1 3 Sorption in Dual Porosity Systems 355 12 MIKE Zero Oy ie scar certs Nese be WN e aa e eevee we serene ease eta Ge a oh de Aa 356 20 3 Plant Uptake sos c2 Aches Based ye ebae eee ue ee OSs Ra aE 359 20 4 Process verification gt fog et cab d owt eee ae Sew aed 360 20 4 1 Other Processes Simulation Examples
39. 222 MIKE SHE Simplified Overland Flow Routing LEA and the relationship between the depth y and the surface storage at equi librium D is given by m 13 32 lt Il n100 gt F The relationship between the depth y and the detained surface storage prior to equilibrium D is given by an empirical model Fleming 1975 Crawford and Linsley 1966 y 2h14 3 5 2 m 13 33 where during the recession part of the hydrograph when D D is greater than 1 D D is assumed to be equal to 1 Substituting 13 33 into the Manning equation 13 21 yields D D i Ba pa he rais 2 m s 13 34 13 2 2 Implementation in MIKE SHE In MIKE SHE the current level of surface detention storage is continually estimated by solving the continuity equation D D Gsupply 4 At 13 35 where D1 is the detained storage volume at the start of the time step and D2 is the detained storage volume at the end of the time step q is the over land flow during the time interval and qsuppiy is the amount of water being added to overland flow during the time step Since q is a function of the average detained storage volume D1 D2 2 equation 13 34 is solved iteratively until a solution satisfies both equations 13 2 3 Coupling to other processes Overland flow interacts with the other process components such as evapotranspiration from the water surface infiltration into the underlying soils interaction with soil drains
40. 45 TestingSNASe bySMIKE11 WMPIII mike1 1 newSNrS oby Autocal EE Edit Inundation Areas Flood Codes I Bathymetry In this dialogue you can link MIKE SHE to a MIKE 11 simulation sim11 file The simulation file is the main MIKE 11 file which contains the file references to the MIKE 11 river network nwk11 cross section xns11 and boundary bnd11 files In principle there are three basic steps for developing an integrated MIKE SHE MIKE 11 model 1 Establish a MIKE 11 HD hydraulic model as a stand alone model make a performance test and if possible a rough calibration using pre scribed inflow and stage boundaries 2 Establish a MIKE SHE model that includes the overland flow compo nent and optionally the saturated zone and unsaturated zone compo nents 3 Couple MIKE SHE and MIKE 11 by defining branches reaches where MIKE 11 should interact with MIKE SHE The chapter Coupling MIKE 11 and MIKE SHE VJ p 165 describes in more detail the three steps above There are two additional options in the above dialogue for calculating inundation areas Flood codes Flood codes are used for the Flood Area Option V1 p 174 in MIKE 11 to indicate which cells flood during a storm event Bathymetry The bathymetry is used to more accurately simulate the topography of the flood code cells when the MIKE SHE topography is specified on a larger grid Related Items e Channel Flow Reference V 2 p 227 80
41. 5 Circle 7616 37 25521 5 meter 35000 Catchment 30000 25000 20000 15000 10000 5000 D 1 u rae 0 10000 20000 30000 meter The initial particle locations can be defined by points lines and circles You can specify any number of particles in this dialogue and all of them will be tracked in the MODPATH simulation Include This checkbox allows you to exclude some particles from the simulation without actually removing them from the list Type You can define single particles a line of particles or a circle of particles Single particles are useful for evaluating the flow direction in areas of interest Lines are useful for determining the influence of bound ary conditions Circles are useful for calculating well capture zones X and Y The X and Y coordinates can be typed in by hand or you can use the target button to interactively locate the particles on the map The second set of X and Y coordinates specify the end point location for parti cle lines MIKE SHE Editors e 199 Particle Tracking Editor 9 5 Depth The depth is depth below ground for the particle location This is translated into a model layer before MODPATH is run In the case of par ticle lines the start point and the end point can be located at different depths Layer The layer option allows you to specify the model layer for the par ticle Radius In the case of particle circles
42. 7 Subcatchments Name Speed River basin Grid code value IV Use default river links Subcatchments Conditions when either of the subcatchment based methods for Overland Flow or Saturated Flow are selected in the Simulation Specification dialogue dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The Subcatchment item appears whenever you select one of the sub catchment based methods Simplified Overland Flow Routing or the Lin ear Reservoir Method for groundwater flow The subcatchment items are used to identify the hydrologic subwatersheds in your model domain For the Simplified Overland Flow Routing the cal culated overland flow in the Overland Flow Zones flows from one zone to the next within the Subcatchment For the Linear Reservoir Method for groundwater flow the calculated interflow is routed from one zone to the next within the Subcatchment For each unique integer code in the main Subcatchment map view an additional data item is added to the data tree In each of these sub items there is only one additional variable a checkbox for using the default river links Use default river links in most cases you will link the simplified over land flow and the groundwater interflow to all of the river links found in the lowest topographic zone or the lowest interflow zone in the sub catchment However in some cases you may want to link the flow to particular river links Fo
43. Flux GS Fixed Head B Zero Flux GB Undefined boundary points L Inner point L Undefined Value 570000 560000 1960000 meter The outer boundary conditions are defined as line segments between two boundary points The boundary points are in principle independent of the model domain because they do not need to lie on the model boundary Rather they are projected onto the nearest model boundary cell Thus the model boundary can be modified slightly without having to modify the boundary locations However if the model boundary is moved signifi cantly or if the boundary is convoluted then the calculated nearest node might not be the one expected Specifying a boundary condition To specify an outer boundary segment 118 MIKE SHE Saturated Zone Se add a new line to the outer boundary points table click on the target icon click on one end of your boundary segment add a second line to the outer boundary points table click on the new target icon click on the other end of your boundary segment Change the name of the top line of the points table o y Dn A U N e Select the appropriate boundary condition for the boundary segment Available boundary conditions Fixed Head This boundary prescribes a head in the boundary cell The head can be fixed at a prescribed value fixed at the initial value from the initial conditions or assigned to a dfsO time series file The last option is a time v
44. If you do not use the overbank spilling option then you can still use the flood inundation option to flood a flood plain In this case though the flooding is not calculated as part of the overland flow but remains part of the water balance of MIKE 11 For more information on the flood inunda tion method see the section on Area Inundation using Flood Codes areal 37 Se Setup Data Tab source sink V 2 p 239 and the Inundation options by Flood Code VI p 173 Threshold head difference for applying low gradient flow reduction If the difference in water level between the river and the overland flow cell is less than this threshold then the flow over the weir is reduced to dampen numerical instabilities In this case the same damping func tion is used as in low gradient areas The damping function essentially increases the resistance to flow between the cell and the river link This makes the solution more stable and allows for larger time steps How ever the resulting gradients will be artificially high in the affected cells and the solution will begin to diverge from the Mannings solution At very low gradients this is normally insignificant but as the gradient increases the differences can become significant The damping function is controlled by a minimum head difference between the river and cell below which the damping function become active Experience suggests that you can get reasonable results with a mini
45. Item number in the dfs0 file Fraction This is a multiplier for the groundwater pumping rate specified in the DFSO File MIKE SHE Editors 169 Se Well editor 5 0 4 Layers Display Geo Layers Calc Layers 40 iS 30 20 3 nnfyn_4 end 10 0 10 nnfyn_5 enda HA ag_ 20 The Layer display section displays the location of all well screens assigned to the well The Geo Layers column displays the geologic layers assigned in the Setup Tab for the well and the Calc Layers is the numeri cal layers for the column of model cells in which the well is located Both the Geo Layers and the Calc Layers items require that the model has been successfully pre processed If you have not pre processed the model yet or if during the preprocessing an error occurred then a warning mes sage dialogue may appear saying that the model must be pre processed first If this happens the Well Editor will function normally but the Geo and Calc layers may not be shown 5 1 Importing Data In the top menu bar there is an Import menu that allows you to import the following well data Zeus data The Zeus data is a specialized data format from the Geologi cal Survey of Denmark and Greenland t0 data The t0 format is a time series file format used by MIKE SHE prior to the MIKE Zero version This is provided for backwards com patibility reasons ASCII files This is the most common way of imported well data 170
46. Land Use V 2 p 62 specification of vegetation and irrigation e Evapotranspiration V 2 p 79 specification and extent of reference evapotranspiration measurements or calculations e Rivers and Lakes V 2 p 80 link to MIKE 11 channel flow model e Overland Flow V 2 p 82 specification of 2D overland sheet flow parameters for both water movement and water quality e Unsaturated Zone V 2 p 90 specification of 1D unsaturated zone columns e Groundwater Table V 2 p 101 specification of static lower bound ary condition for unsaturated flow if saturated zone not included e Saturated Zone V 2 p 102 specification of 3D saturated zone parameters for both water movement and water quality e Sources V 2 p 130 location and extent of solute sources for water quality simulation e Storing of Results V 2 p 135 output selection for calibration time series and gridded data 19 Setup Data Tab 2 1 Display e Extra Parameters V 2 p 144 extra input data for model options not yet available in the data tree r Import Lower Left comer Upper Right comer x 1578000 Y 6118000 x 1600500 Y 6140500 meter 6140000 4 3 TT 0145 8 r i From this dialogue and data tree branch you can control the map overlays and size of the map view in the rest of the dialogues In any map view in the Setup Data tab you can right click and chose Zoom In from the pop up
47. Layer or Lense or Water Quality Layer 111 2 16 7 Upper Level 2 66 42 deme ee be Bee ow wee oS 111 2 16 8 Horizontal Extent gb bw ee bee ee ee ee ee 111 2 16 9 Geological Unit Distribution 112 2 16 10 Horizontal Hydraulic Conductivity 112 2 16 11 Vertical Hydraulic Conductivity 113 2 16 12 Specific Yield 24 25 Sond bx be Saw Saka bete a 114 2 16 13 Specific Storage na a ee ee eae ee 114 2 16 14 Porosity 224426569044 O04 YG eS BS he SSS we 115 2 16 15 Dispersion Coefficients LHH THH TVH LVV THV 115 2 16 16 Computational Layers o oo 116 2 16 17 Lower Level Numerical Layer 117 2 16 18 Initial Potential Head ww we aaa ee 117 Se 2 16 19 Outer boundary conditions 118 2 16 20 Internal boundary conditions 121 2 16 21 Initial concentration 000000088 123 2 16 22 Drainage nce he Kerk Bw 2 Ole Gace Kees a 123 2 16 23 DrainLevel rigg radan pki ee 125 2 16 24 Drain Time Constant 126 2 16 25 Drain CodeS 20020000000 127 2 16 26 Option Distribution sw eae ee a ee a a ee 128 2 16 27 Pumping Wells aa om Oo Oem sd Ohe haeee ae ae 129 2 17 SourceS 1 ee 130 2 il a EXET oen a me Pa EE 132 2172 FOP Elevation seee wd dye hw ay ew eee eee 133 2 17 3 Bottom Elevation 0 000000 0 2 ee 133 2 17 4 Strength 646 e
48. MIKE SHE Rivers and Lakes LAA e Coupling of MIKE SHE and MIKE 11 V 2 p 228 e River Aquifer Exchange line source link V 2 p 234 e Area Inundation using Flood Codes areal source sink V 2 p 239 e Direct Overbank Spilling to and from MIKE 11 V 2 p 240 e Coupling MIKE 11 and MIKE SHE VJ p 165 e MIKE 11 Cross sections VJ p 166 e MIKE SHE Coupling Reaches V p 169 2 12 1 Flood codes Flood Codes Conditions If Rivers and Lakes selected in the Simulation Specification dialogue and Flood Codes selected in the River and Lakes dia logue dialogue Type Integer Grid Codes EUM Data Grid Code Units Flood codes are required when coupling MIKE 11 with the Inundation options by Flood Code This requires a dfs2 file with Integer Grid Codes which are then used for making the flood mapping for the coupling reaches Related Items e Area Inundation using Flood Codes areal source sink V 2 p 239 e Flood Area Option V 1 p 174 e Inundation options by Flood Code V p 173 81 Se Setup Data Tab 2 12 2 Bathymetry Bathymetry Conditions If Rivers and Lakes selected in the Simulation Specification dialogue and Bathymetry selected in the Rivers and Lakes dia logue dialogue Type Stationary Real Data EUM Data Elevation Units The bathymetry option allows you to specify a detailed flood plain and river bottom topography which can then be used for more accurate defini t
49. Only store hot start data at the end of the simulation Typically the follow on simulation starts at the end of the previous simulation How ever if you want to test the sensitivity of the results to the starting con dition for example you may want to save hot start data more 135 Setup Data Tab frequently However the hot start file can become very large if the hot start data is saved frequently Store AD input data during water movement simulation A MIKE SHE water quality simulation is calculated based on the cell by cell water fluxes calculated by the water movement module If water qual ity is included in the model setup then the necessary data is automati cally saved and this item is hidden However if water quality is not included in the simulation you can optionally tell MIKE SHE to save the necessary data for the water quality model by checking this box on and selecting the save option The first option only saves the saturated zone data which is suitable if you are only going to calculate the water quality in the saturated zone For example the random walk particle tracking is only available in the saturated zone and there is therefore no need to save overland flow data for a particle tracking simulation The second option saves all of the data necessary for a water quality simulation in the complete integrated model Storing interval for grid series output Gridded output can create very large output files i
50. SZ drainage network Activating the Paved areas option creates a sub tree with the Paved Runoff Coeffi cient V 2 p 68 The Paved areas option is available only when Over land flow is simulated Check water level before routing to river If this option is checked then MIKE SHE checks to make sure that the water level in the receiv ing river is lower than the drain level in the current cell If the river is higher than the drain level then no paved runoff will occur Irrigation The Irrigation option allows you to specify a demand driven irrigation scheme with priorities Activating the Irrigation option cre ates several sub items in the data tree for the irrigation parameters The Irrigation option requires that both Evapotranspiration and Unsaturated Flow be simulated For more information see Irrigation Command Areas V 2 p 69 Priority Scheme The priority scheme is used by the Irrigation module to rank the model areas in terms of priority for irrigation Two options are allowed Equal Volume or Equal Shortage If the water is to be distrib uted based on equal volume then all cells with the same priority number will receive an equal amount of water regardless of their actual demand If the water is to be distributed based on equal shortage then all cells with the same priority number will receive an amount of water that satisfies an equal percentage of their actual demand For more information see Irrigation Priorities V 2 p 7
51. Solute Transport in Overland Flow V 2 p 344 e Source Sinks Boundary Conditions and other Exchanges V 2 p 348 in overland flow 134 MIKE SHE Storing of Results LAA 2 18 Storing of Results I Default output folder Folder name c Work main Products S ource MSHE RegT est 4D Karup KarupF or4D a Default output folder If you unselect this option then you can change the output folder for the results If you change the output folder then you must re run the model for the Results tab to point to the correct folder Water Movement Output Water Movement Output IV Storing of Water balance IV Storing of input data for WO simulation C Store SZ flow data only IV Storing of Hot start data Store all flow data T Only store Hot start data at the end of simulation Hot start storing interval fi hrs Storing interval for grid series output Overland OL Prec SM ET UZ S2 Heads SZ Fluxes e hrs e hrs 148 hrs 148 hrs Storing of water balance data When this option is selected MIKE SHE will store all of the relevant output data for the analysis of the water balance This will automatically select the required items in the Grid Series Output section Storing of Hot start data The option allows you to save a simulation that can be used as the start a new simulation See Time Step Control for more information on using Hot Start data as the initial data for a simulation
52. Table 19 1 Internal boundary source sinks between hydrologic components in MIKE SHE AD Solutes from Primary solute sink Alternative solute sink if primary sink unavailable Precipitation Fluxes Overland flow Unsaturated zone or Groundwater Overland Fluxes Infiltration Unsaturated zone Groundwater Overland flow MIKE 11 External boundary Drainage from paved areas MIKE 11 none Unsaturated Zone Fluxes Infiltration Groundwater External Boundary Bypass flow Groundwater External Boundary Groundwater Fluxes SZ Drainage MIKE 11 Overland flow or External boundary Upward flux to overland Upward flux to UZ Overland flow Unsaturated Zone none Overland flow Baseflow to streams MIKE 11 none MIKE 11 Baseflow to groundwater Groundwater none An sketch of the different internal boundary conditions is shown in Figure 19 1 Each of these exchanges is detailed in the respective sub sec tion for each hydrologic component 326 MIKE SHE User s Guide Simulation control LAA WY SZ TO SINKS Ula OVERLAND TO f PRECIPITATION 4 FROM RIVER TO OVERLAND BOUNDARY BOUNDARIES TO FROM OVERL TO RIVER OVERLAND TO UZ UZ TO FROM SZ BOUNDARIES TO FROM SZ Figure 19 1 Outline of the different transport possibilities between components and boundaries 19 1 3 Time step calculations The time scales of the various transport processes are
53. The difference between Oax and the actual moisture content is the storage capacity of the unsaturated zone Vertical infiltration to the saturated zone will only occur when the water content is equal to Omax If the water table is below the ET extinction depth then a lower ET layer exists The moisture content of the lower ET layer is equal to the field capacity which is the minimum water content when ET does not exist Technical Reference for Water Movement 257 LEA Evapotranspiration Reference The average moisture content of the upper ET layer can range between the field capacity Orc and the wilting point Owp which is the minimum water content at which the plants can remove water from the soil 15 2 4 Infiltration At the beginning of each computational time step rainfall first fills the interception storage If Zmax is exceeded the excess water is added to the amount of ponded water on the ground surface doc which is the height of surface ponding before infiltration is subtracted Next the maximum infiltration volume is limited by the rate of infiltra tion Thus Inf King At where Inf is the maximum amount of infiltration allowed during the time step due to the infiltration rate K is the infiltration rate and At is the cal culation time step The maximum infiltration volume is also limited by the available storage volume in the unsaturated zone which is calculated by Inf Orar 0 1 Zwt whe
54. Transport Limit The transport limit restricts the fraction of the total amount of mass that can leave the cell in one time step The default value 0 95 which usually does not limit the time step 2 4 Species Species_1 Iv Species_2 Solute Species Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue In this dialogue you add species by clicking on the Insert icon You delete species by selecting the species from the table and clicking on the Delete icon The table includes the list of species for the WQ simulation and the physi cal properties of the chemical species Include Turning off the include checkbox allows you to exclude a spe cies from the simulation without having to remove it and all of its accompanying sources etc 50 MIKE SHE Species Parameters es Name This is the displayed identifier in all subsequent dialogues and in the data tree Type At the moment Solute is the only active type However in future versions other types may be available Mobility The mobility refers to the ability of the species to move with the water A species can be Mobile or Immobile The distinction is made because mobile and immobile versions of the same chemical can have different reaction rates such as half life Also when a mobile spe cies absorbs to the soil grains then it becomes part of the immobile vers
55. a new iteration will be started This will continue until the maximum number of iterations is reached The default value is 0 0001 m which is normally reasonable Maximum residual error If the difference in water level between itera tions divided by the time step length in any grid cell is greater than this amount then a new iteration will be started This will continue until the maximum number of iterations is reached The default value is 0 0001m d which is normally reasonable Under relaxation factor The change in head for the next iteration is mul tiplied by the under relaxation factor to help prevent numerical oscila tions Thus lowering the under relaxation factor is useful when your solution is failing to converge due to oscillations This will have the affect of reducing the actual head change used in the next iteration However often it is more effective to reduce the time step The under relaxation factor must be between 0 01 and 1 0 The default value is 0 9 which is normally reasonable Explicit parameters Maximum courant number The courant number represents the ratio of the speed of wave propagation to the grid spacing In other words a courant number greater than one would imply that a wave would pass through a grid cell in less than one time step This would lead to severe numerical instabilities in an explicit solution The courant number must be greater than 0 1 and less then 1 0 For a detailed discussion of the co
56. a limiting solute flux per time step 19 2 Solute Transport in the Saturated Zone The solute transport module for the saturated zone in MIKE SHE allows you to calculate transport in 3D 2D layer 2D or even 1D However the transport formulation is controlled by the water movement discretisation If the vertical discretisation is uniform except for the top and bottom layer the transport scheme is described in a fully three dimensional numerical formulation If the numerical layers have different thicknesses a multi layered 2D approach is used where each layer exchanges flows with other layers as sources and sinks If you specify a 1D or 2D flow sim ulation the transport formulation is further simplified Temporal and spatial variations of the solute concentration in the soil matrix are described mathematically by the advection dispersion equation and solved numerically by an explicit third order accurate solution scheme The forcing function for advective transport is the cell by cell groundwa ter flow as well as groundwater head boundary drain and exchange flows which are all read from the WM results files Solute exchange between the other hydrologic components is generally simulated by means of explicit sources and sinks Technical Reference for Water Quality 329 a oe Advection Dispersion Reference 19 2 1 Governing Equations The transport of solutes in the saturated zone is governed by the advec tion dispersio
57. an intelligent grouping of the cells can reduce computational burden considerably The initial definition of homogeneous zones can be made using the depth to the groundwater table and the soil vegetation and rainfall distributions It is often necessary to re group the columns several times during the cali bration phase until the groundwater regime is reasonable calibrated Also when the groundwater table is shallow smaller intervals are usually required 16 6 Coupling the Unsaturated Zone to the Saturated Zone Briefly the interaction between the unsaturated and saturated zones is solved by an iterative mass balance procedure where the lower part of the unsaturated node system may be solved separately in a pseudo time step between two real time steps This coupling procedure ensures a realistic description of the water table fluctuations in situations with shallow soils Particularly in these cases it is important to account for a variable specific yield above the water table as the specific yield depends on the actual soil moisture profile and availability of that water The recharge to the groundwater is determined by the actual moisture dis tribution in the unsaturated zone A correct description of the recharge process is rather complicated because the water table rises as water enters the saturated zone and affects flow conditions in the unsaturated zone The actual rise of the groundwater table depends on the moisture profile abo
58. assumed strictly verti 340 MIKE SHE User s Guide Solute Transport in the Unsaturated Zone LA cal this restriction applies also to the advective transport of the dissolved solutes To determine the velocity v the flux is divided by the moisture content q v 4 19 18 6 The mathematical formulation of the dispersion of the solutes follows the formulation derived for groundwater flow with a linear relation between the dispersion coefficient and the seepage velocity but limited to one dimension In this case the dispersion coefficient can be written as D ayy 19 19 where az is the longitudinal dispersivity of the porous medium which rep resents the heterogeneity of the soil hydraulic parameters a is allowed to vary vertically to account for different degrees of inhomogeneity in the soil For unsaturated flow the dispersivity is dependent on the water con tent however this relationship is neglected Macro pore transport 19 3 2 Solution Scheme Similar to the saturated zone the unsaturated solute transport is solved explicitly using upstream differencing for the advection term and central differencing for the dispersion term Neglecting the dispersion terms and the source sink term and assuming that the flow field satisfies the equation of continuity and varies uniformly within a grid cell the advection component is Be i cal hal ON E a sc 19 20 Technical Reference for Water Qua
59. channel flow Related Items e Adding Overland Flow V p 46 e Overland Flow Reference V 2 p 211 2 13 2 Detention Storage Detention Storage Conditions when Overland Flow the Finite Difference method is selected in the Simulation Specification dialogue dialogue Type Stationary Real Data EUM Data Storage Depth Units Detention Storage is used to limit the amount of water that can flow over the ground surface The depth of ponded water must exceed the detention storage before water will flow as sheet flow to the adjacent cell For exam ple if the detention storage is set equal to 2mm then the depth of water on the surface must exceed 2mm before it will be able to flow as overland flow This is equivalent to the trapping of surface water in small ponds or depressions within a grid cell Water trapped in detention storage continues to be available for infiltration to the unsaturated zone and to evapotranspiration Using detention stor age you can simulate water that is trapped in depressions that are smaller than a grid cell Related Items e Adding Overland Flow V p 46 e Overland Flow Reference V 2 p 211 84 MIKE SHE Overland Flow LEA 2 13 3 Initial Water Depth Initial Water Depth Condition when Overland Flow the Finite Difference method is selected in the Simulation Specification dialogue dialogue Type Stationary Real Data EUM Data Units Water Depth This is the i
60. creating the pressure head under unsaturated and saturated conditions are very different the pressure head is considered to be a continuous function across the water table with the pressure being negative above and positive below the water table For vertical flow the driving force for the transport of water is the vertical gradient of the hydraulic head Thus eee 16 2 Oz The volumetric flux is then obtained from Darcy s law oh q K0 16 3 where K O is the unsaturated hydraulic conductivity Assuming that the soil matrix is incompressible and the soil water has a constant density the continuity equation will be 08 _ _ a 7 BETS 16 4 262 MIKE SHE Richards Equation Se where 9 is the volumetric soil moisture and S is the root extraction sink term Combining Eqs 16 1 16 3 and 16 4 yields 2 Oy _ 2KO a O E a TS 16 5 The dependent variables O and y in Eq 16 5 are related through the hydraulic conductivity function K and the soil moisture retention curve y Eq 16 5 is general in the sense that it is equally valid in both homoge neous and heterogeneous soil profiles and there are no constraints on the hydraulic functions Introducing the concept of soil water capacity a Il Z 16 6 Q lt which is the slope on the soil moisture retention curve then the tension based version of Eq 16 5 is Oy _ 2f pr OV 2KO c2 x o Ws 16 7 This e
61. difference between the MIKE SHE 3D Finite Difference Method numerical engine and MODFLOW In fact they share the same PCG solver The differences that are present are lim ited to differences in the discretisation and to some differences in the way some of the boundary conditions are defined Linear Reservoir Method T Include pumping wells Setting up a saturated groundwater model using the Linear Reservoir Method involves defining the Interflow and Baseflow Reservoirs as well as their respective properties Pumping wells By default wells are not included but in most applications pumping wells play a major role in the hydrology of the area If wells are included in the model then this must be checked and a new item in the data tree appears where the well database can be defined Pumping wells extract water only from the baseflow reservoirs 102 MIKE SHE Saturated Zone LAA Related Items e Saturated Flow Reference V 2 p 289 e Linear Reservoir Method V 2 p 307 3D Finite Difference Method T Include pumping wells J Include subsurface drainage M Hydrogeologic parameter distribution Assign parameters via geological layers C Assign parameters via geological units within layers m Dispersion No Dispersion C Isotropy C Anisotropy Mass transfer to immobile water Setting up a saturated zone hydraulic model based on the 3D Finite Differ ence Method involves defining the
62. different For exam ple the transport of solutes in a river is much faster than transport in the groundwater The optimal time step is different for each component where optimal can be defined as the largest possible time step without introducing numerical errors In addition the optimal time step varies in time as a consequence of changing conditions in the hydrological regime within the catchment Different time steps are allowed for the different components However an explicit solution method is used which sometimes requires very small time steps to avoid numerical errors The Courant and Peclet numbers play an important role in the determination of the optimal time step The user can specify the maximum time step in each of the components However the actual simulation time step is controlled by the stability cri terions with respect to advective and dispersive transport as well as the timing of the sources and sinks and the simulation and storing time steps in the WM simulation In Figure 19 2 you can see an example of the sequence of calling each components in the MIKE SHE advection dispersion module The time Technical Reference for Water Quality 327 LEA Advection Dispersion Reference step in the river transport calculation is usually the smallest whereas time step for groundwater transport is always the largest A transport simulation begins with the overland component followed by MIKE 11 the unsaturat
63. dis persivities should be Whereas the larger the grid size the smaller the dis persivities should be due to numerical dispersion Thus it is difficult to give a rule of thumb for the values of dispersivity Recent field experiments on solute transport though indicate that the lon gitudinal dispersivity should be in the range of 1 or less of the travel dis tance the transverse horizontal dispersivity should be at least 50 times less than this and the transverse vertical dispersivity should be 2 or more times less than the transverse horizontal Related Items e Saturated Zone V 2 p 102 e Solute Transport in the Saturated Zone V 2 p 329 2 16 16 Computational Layers C Defined by geological layers Explicit definition of lower levels fos m M Type of Numerical Vertical Discretization Bottom Elevation Correction Minimum layer thickness Limestone The vertical discretisation in the saturated zone can be defined in two ways 116 MIKE SHE Saturated Zone Se e by the geological layers in which case there will be one calculation node in each geological layer e by explicitly defining the lower level of each calculation layer Vertical discretisation Defined by the geological layers Groundwater flow in a multi layer aquifer can be described by a model in which the computational layers follow the interpreted geological layers Each layer is characterised only by its base level spec
64. drainage into the channel network etc This is an integral part of the MIKE SHE framework and these interac tions are treated in the same manner in both the Semi distributed Overland Technical Reference for Water Movement 223 Overland Flow Reference Flow Routing model and the 2D Finite Difference Method based on the diffusive wave approximation The Semi distributed Overland Flow Routing model simulates flow down a hillslope To apply this at the catchment scale it is assumed that the overland flow response for a catchment is similar to that of an equivalent hillslope Furthermore the drainage of overland flow from one catchment to the next and from the catchment to the river channels is represented conceptually as a cascade of overland flow reservoirs 13 2 4 Avoiding the redistribution of ponded water In the standard version of the Simplified Overland Flow solver the solver calculates a mean water depth for the entire flow zone using the available overland water from all of the cells in the flow zone During the Overland flow time step ET and infiltration are calculated for each cell and lateral flows to and from the zone are calculated At the end of the time step a new average water depth is calculated which is assigned to all cells in the flow zone In practice this results in a redistribution of water from cells with ponded water e g due to high rainfall or low infiltration to the rest of the flow zone whe
65. exchange flow between the flooded grid cells and the over land saturated unsaturated zone or other source sink terms is fed back to MIKE 11 as lateral inflow or outflow to the corresponding H point in the next MIKE 11 time step In terms of the water balance the surface water in the inundated areas belongs to the MIKE 11 water balance In other words if there is ponded water on the surface when the grid cell floods the existing ponded water is added to the MIKE 11 water flow in the river As long as the element is flooded any exchange to or from the surface water is managed by MIKE 11 as lateral inflow and regular overland flow is not calculated If the element reverts back to a non flooded state then any subsequent ponded water is again treated as regular overland flow and the water bal ance is accounted for within the overland flow component 14 4 Direct Overbank Spilling to and from MIKE 11 If you want to calculate 2D overland flow on the flood plain during a storm event then you cannot use the Area Inundation using Flood Codes areal source sink V 2 p 239 method The Area Inundation method is primarily used as a way to spread river water onto the flood plain and make it available for interaction with the subsurface via infiltration and evapotranspiration The Overbank spilling option treats the river bank as a weir When the overland flow water level or the river water level is above the left or right bank elevation then w
66. for a single command area The order of the sources in the table is also their priority For example in the figure above as long as there is suffi cient water in the river the irrigation water will be removed from the river If the River falls below a specified level and or discharge then the irriga tion water will be taken from the single well and so on 70 MIKE SHE Land Use River Source River source MV Use threshold river discharge River Name Stop Restart Speed River River discharge 2 2 25 nes River Chainage 32456 m V Use threshold river stage Stop Restart Max rate ME m s River stage 230 230 25 m To use a MIKE 11 river as a source of water you must specify the MIKE 11 location to be used followed by the permitted river conditions that allow water to be removed The River source actually has two conditions that can be used alone or combined River Name The MIKE 11 Branch name of the river source This name must exist in the MIKE 11 model and it must be spelled correctly River Chainage The MIKE 11 chainage location to use for the river source The model will find the nearest MIKE 11 H point and use this for the river source Max rate This is the maximum extraction rate for the river If more water is required for irrigation then the next source will be activated Use threshold river discharge If the flow rate in the river falls below the Stop value then water will no longer be taken
67. for overland flow Technical Reference for Water Movement 227 Se Channel Flow Reference e Area Inundation using Flood Codes areal source sink V 2 p 239 The river has a wide cross section containing the flood plain and desig nated cells are flooded if the river water level is above the topogra phy e Direct Overbank Spilling to and from MIKE 11 V 2 p 240 The river is a line source sink but water above the bank elevation is allowed to flood onto the topography as overland flow The above options can be mixed in the MIKE 11 river network allowing for example Flood Codes in the major flood plain and overbank spilling in the upstream secondary branches but no flooding in the upland regions with steep slopes and narrow channels MIKE SHE also automatically converts between the line source sink option and the flooding options Thus during low flow conditions when the river is narrow less than one grid size and water flow is confined to the main river channel the river aquifer exchange method is adopted If the river starts to flood one or more model grid cells MIKE SHE switches to the area inundation method or floods the grid cells directly via overbank spilling 14 1 Coupling of MIKE SHE and MIKE 11 The coupling between MIKE 11 and MIKE SHE is made via river links which are located on the edges that separate adjacent grid cells The river link network is created by MIKE SHE s set up program based
68. from the River However if the flow rate in the river increases again and reaches the Restart value the river source will be reactivated Use threshold river stage If the water level in the river falls below the Stop value then water will no longer be extracted from the River However if the water level in the river increases again and reaches the Restart value the river source will be reactivated If both threshold values are specified then the most critical one is used and the source will not restart until both are satisfied Note There is no restriction on the number of river sources at a location However if the sources are located in the same model grid then a warning message will be printed to the projectname_preprocesssor_messages log file The sources will be merged retaining the maximum threshold stages and the sum of the capacities The preprocessor also checks the license application volume to make sure these are the same If not the preproces sor will stop with an error 71 Se Setup Data Tab Single Well Source Single well source Pos Max depth to water Top of screen 341290 m 8 m 0 m Y Pos Max rate Bottom of screen 563210 m 0 35 m s 14 m To use a well source in the model you must specify the location and filter depth of the well In a future release this dialogue will be connected to the well database but at the moment it is not X Y Pos This is the X and Y map coordi
69. hours etc 33 a Setup Data Tab 2 2 4 OL Computational Control Parameters Maximum courant number 04 0 3 for adaptive time step Overland Computational Control Parameters Conditions if Overland Flow specified in Model Components Variable Units Maximum number of iterations Maximum head change per iteration m Maximum residual error m d Under relaxation factor Maximum courant number s Threshold water depth for overland flow m 34 MIKE SHE Simulation Specification LEA Variable Units Threshold gradient for applying low gradient flow reduction Threshold head difference for applying low gradient flow reduction Solver Type for Overland Flow Overland flow can be solved using either using the implicit Successive Over Relaxation SOR Numerical Solution V 2 p 216 or an Explict Numerical Solution V 2 p 217 In the SOR method the depth of overland flow is solved iteratively implicitly using a Gauss Seidel matrix solution The SOR method is a means of speeding up convergence in the Gauss Seidel method The itera tion procedure is identical to that used in the saturated zone except that no over relaxation is allowed The SOR method is faster but not as accurate compared to the Explicit method However when calculating overland flow to generate runoff the SOR method is typically accurate enough The Explicit method is typically much
70. is assumed Typically the soil moisture curve is measured in a laboratory or assumed based on typical values for similar soils If laboratory data is available the measured y values can be input directly into MIKE SHE as tabular data MIKE SHE Editors 173 UZ Soil Properties Editor 6 1 1 6 1 2 6 2 Intermediate values are then calculated by MIKE SHE using a cubic spline method and stored internally in the code Alternatively the meas ured values can be fitted to commonly used functional relationships The appropriate function parameters can be input directly or more refined tab ular data may be generated externally to MIKE SHE e g in MS Excel and input as tabular data Several parametric forms of the soil moisture retention curve have been developed over the years The MIKE SHE interface allows the user to specify several of these parametric forms The pF field capacity is used as the initial condition in the unsaturated flow module The pF wilting is the lower limit at which water can be removed via evapotranspiration The data points describing the pressure conductivity curve can be given as a table of pF versus O moisture content values The table should be spec ified starting with the lowest value of pF wettest condition and given in increasing order of pF To get a smooth retention curve MIKE SHE adopts a cubic spline curve fitting procedure As a minimum you should specify the conductivi
71. is the conductance from surface level to the middle of the top calculation layer In case of full contact between overland and the saturated zone the con ductance between overland and layer 1 is computed as CG 17 16 where Az is the thickness of layer 1 and K is the vertical conductivity of layer 1 In areas with reduced contact between overland and the saturated zone the conductance between the overland flow and layer 1 is calculated by Ax Az 1 2K Keak G 17 17 where Az is the thickness of layer 1 and K is the vertical conductivity of layer 1 and K is the specified leakage coefficient 17 1 4 Initial Conditions The initial conditions are specified in the Setup Editor and can be either constant for the domain or distributed using dfs2 or shp files The initial conditions in boundary cells are held constant during the simulation which means that the initial head in cells with Dirichlet s boundary condi tions is the boundary head for the simulation 17 1 5 The Sheet Pile Module The Sheet Piling module is an add on module for the PCG groundwater SZ solver in MIKE SHE that allows you to reduce the conductance between cells in both the horizontal and vertical directions Vertical sheet piling reduces the horizontal flow between adjacent cells in the x or y direction It is defined by a surface with a specified leakage coefficient located between two MIKE SHE grid cells in a specified comput
72. is the root water uptake and c is the liquid concen tration 20 4 Process verification The performance of MIKE SHE s basic reactive transport module with equilibrium and non equilibrium sorption and degradation has been veri fied against analytical solutions calculated with CXTFIT Toride et al 1995 The verification tests were conducted using steady state saturated water flow through a 1 m deep column discretised in 5 cm elements The simulations were run for one month with maximum time step equal to 15 min Pore flow velocity was 25 cm day the dispersivity was 1 cm and the bulk density was 1 5 g cm Furthermore the diffusion process in frac tured media with a fracture porosity of 0 25 and a matrix porosity of 0 05 is verified both without and with sorption The verification results confirm that the numerical solutions are satisfac tory since the calculated solute breakthrough and mass recovery curves are very similar to the analytical solutions 360 MIKE SHE User s Guide Process verification a oe c c0 Relative concentration A Fraction of mass recovery Td 1 2 mig i Kd 1 3 mvg Kd 1 6 mVg Kd 1 6 m9 Kd 0 mi g Kd 0 ml g MIKE SHE Figure 20 5 Linear equilibrium sorption Effect of Ky ml g in Eq 20 2 Technical Reference for Water Quality 361 a oe Reactive Transport Reference c Relative concentration KI 0 16 1 d f 05 K1 0 08 1 d
73. length 136 MIKE SHE Storing of Results a Water Quality Output gt Water Quality output Storing interval for grid series output Overland OL Unsaturated Zone Saturated Zone 2a hrs 24 hrs a4 hrs M Storing interval for mass balance output Time Series dfs0 Summary ASCll 24 hrs 24 hrs Storing interval for grid series output similar to the storing interval for water movement data the gridded output data files for a detailed transport simulation can get very large These three frequencies allow you to save only the data you need Storing interval for mass balance output similar to the storing interval for grid series output these separate storing frequencies allow you to save only the data you need Related Items e Time Step Control V2 p 30 e Detailed time series output V 2 p 138 e Grid series output V2 p 143 137 oa Setup Data Tab 2 18 1 Detailed time series output 146 532 DKS head elevation in saturated zone Vv 146 1936 DK head elevation in saturated zone Vv 146 2040 DK head elevation in saturated zone S88873 6 1288e 00 54 amp Vv 590623 6 13409e 0 20 amp 594593 6 13035e 0 35 amp 146 633 DK3 head elevation in saturated zone 589597 6 12972e 0 21 ET AAC CTO DID band mla intinm im mahi makan meam conets e aanata n are ats a i A x Y Depth Obs Obs Data Filename Data 590623 6 13409e 0
74. limit on the amount of solute that can be sorbed The Langmuir sorption isotherm takes this into account When all sorption sites are filled sorption ceases The Lang muir isotherm is often given as lt T 5 20 7 C or 20 c l ac Aa where a is a sorption constant related to the binding energy and is the maximum amount of solute that can be absorbed by the soil material The relationship between a and B is shown in Figure 20 2 1 25 peeeseenseeneesnsnnensnsnsesnseaeausn eases sn snemememsnemsmemenememensseaesuseaeeesnseatersnsearenseaensnsearersemrend Gg Qf a 0 5 gt Q 1 Q 5 Sorbed concentration a 05 a 10 0 25 a 50 0 0 25 05 O75 1 125 15 1 75 2 15 b a 5 E a ome osoo o a menencncasncn 2 me f 0 1 E 1 0 3 n E 0 75 p 0 5 g k 0 7 y os Stil K i fm l f g 0 25 1 2 0 0 25 0 5 0 75 4 4 25 15 4 75 2 Liquid concentration Figure 20 2 Illustration of the Langmuir isotherm a effect of change in a b effect of change in B 354 MIKE SHE User s Guide Sorption ae 20 1 2 Kinetic Sorption lsotherms The three equilibrium sorption isotherms described so far can be extended to include kinetically controlled sorption In the MIKE SHE AD module a two domain approach is used where the sorption is assumed to be instan taneous for a fraction of the sorbed solute and rate controlled for the re
75. menu The enlarged view of your map is persist ent across all of the map views in the Setup Data tab as well as to the Processed Data tab Also in the right click pop up menu is a Zoom Extents function which zooms the map view out to the full extents By default the maximum extents of the map view in the MIKE SHE dialogues is set to the size of the model as defined in the Model Domain and Grid dialogue However un checking the checkbox Default map display based on the Model Domain you can chose to set the lower left and upper right coordinates of the max imum extents of the map view Import The Import button allows you to read the coordinate extents from a map file such as a dfs2 file or a shp file Related Items e Model Domain and Grid V 2 p 52 20 MIKE SHE Display 2 1 1 Foreground Background 4 Shape m CS Testingt Pejinger alle _pejlinger shp Shape CAS Testing GISINDSATS SHP Shape C iS Testing GISAMTSVANDLOEB SHP 4 Image V CiS Testingi ImagesMidtF yni BMP 5 Shape WM C 5 Testing GIS model_area shp The Foreground and Background items are used to add map overlays to the map view The table gives you an overview of the defined overlays and allows you to add delete and hide overlays The order of the overlays in the list controls to some extent the way the overlays are displayed Furthermore the Foreground Background choice determines whether the overlay
76. model Recent labora tory and field research have shown a relationship between the spatial vari ability of hydrogeologic parameters and the dispersivities However it is still difficult to obtain sufficient knowledge about the spatial variability of for example the hydraulic conductivity to determine macro dispersivities applicable for solute transport models Technical Reference for Water Quality 333 LEA Advection Dispersion Reference 19 2 2 Solution Scheme Regular Grid The numerical solution to the advection dispersion equation in MIKE SHE AD is based on the QUICKEST method Leonard 1979 originally introduced this method which was further developed by Vested et al 1992 It is a fully explicit scheme which applies upstream differencing for the advection term and central differencing for the dispersion term The equations are developed to third order and the scheme is mass con servative When the vertical discretisation is defined in a regular grid with uniform thickness of all layers except the upper and the lower ones the numerical scheme follows the fully three dimensional formulation below Neglecting the dispersion terms and the source sink term and assuming that the flow field satisfies the equation of continuity and varies uniformly within a grid cell the advection dispersion equation may be written in mass conservation form as vee 0 Y 19 10 jk 1 1 ik 1 1 j 1 k 1 j 1 k
77. multiple of the Max allowed OL time step and The Max allowed SZ time step must be an even multiple of the Max allowed UZ time step Thus the overland time step is always less than or equal to the UZ time step and the UZ time step is always less than or equal to the SZ time step If you are using the implicit solver for overland flow then a maximum OL time step equal to the UZ time step often works However if you are using the explicit solver for overland flow then a much smaller maximum time step is necessary such as the default value of 0 5 hours If the unsaturated zone is included in your simulation and you are using the Richards equation or Gravity Flow methods then the maximum UZ time step is typically around 2 hours Otherwise a maximum time step equal to the SZ time step often works Groundwater levels react much slower than the other flow components So a maximum SZ time step of 24 or 48 hours is typical unless your model is a local scale model with rapid groundwater surface water reac tions Increment of reduced time step length Increment rate This is a factor for both decreasing the time step length and increasing the time step length back up to the maximum time step after the time step has been reduced See Parameters for Precipitation 31 Setup Data Tab dependent time step control V 2 p 32 for more details on when and how the time step is changed A typical increment rate is about 0 05 Par
78. nificant when compared to subsequently solving the equations and the option is only recommended in steady state cases Under relaxation by user defined constant factor This option allows the user to define a constant relaxation factor between 0 0 and 1 0 In general a value of 0 2 has been found suitable for most sim ulations 2 norm reduction criteria in the inner iteration loop When the 2 norm option is active the inner iteration loop of the PCG solver ends when the specified reduction of the 2 norm value is reached Thus if the 2 norm reduction criteria is set to 0 01 the inner iteration residual must be reduced by 99 before the inner iteration loop will exit This option is sometimes efficient in achieving convergence in the linear matrix solution before updating the non linear terms in the outer iteration loop It may thus improve the convergence rate of the solver Continued iterations to meet user defined criteria in the inner loop may not be feasi ble before the changes in the outer iteration loop have been minimised On the other hand very few iterations in the inner loop may not be sufficient The 2 norm may be used to achieve a more optimal balance between the computational efforts spent in the respective solver loops Convergence is however not assumed until the user defined head and water balance criteria are fulfilled A reasonable value for the 2 norm reduction criteria has been found to be 0 01 17 1 2 PCG Steady Sta
79. numeric engine dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The first part of the soil profile definition is to define the areas with the same soil profiles Below this initial item a separate item will appear for every unique Grid Code in the file in which the soil profile is defined see below In this dialogue the distribution of soil layers i e depth and thickness of each soil type in the individual profiles can be specified as well as the vertical discretisation of the soil profile In the soil profile dialogue there are four sections 93 LEA Setup Data Tab Header The header includes the Profile ID which is the editable name displayed in the data tree for this profile and the Grid Code value which is read from the Grid Code file Soil Profile The soil profile section allows you to define the vertical soil profile Soil layers can be added deleted and moved up and down using the icons From and To Depths refers to the distances to the top and bottom of the soil layer below the ground surface Only the To Depth item is editable as the From Depth item is equal to the bottom of the pre vious layer Soil name is the name of the soil selected in the UZ Soil Property file It is not directly editable but must be chosen from the list of available soil names when you assign the UZ Soil property file using the file browser UZ Soil property file is the file name of
80. of executables does not include the APV functions The format of the input file is shown below Note This file is automatically generated from the GUI Line item Comment Created 2006 12 6 13 13 55 DLLid C PROGRA 1 COMMON 1 DHI MikeZero pfs2004 dll PFS version Dec 4 2006 20 53 34 MODPATH_Parameters The first 5 lines are header lines and should not be modified PointLocation test_PTPos1 txtl Path and file name for the initial parti cle locations SheresFile KarupForAD sheres Path to the catalogue file for the MIKE SHE results ResultName test_PTRes1 File name suffix for the output files Start 10 02 1981 The start date must be within the WM flow simulation period If the start date does not match a saved storing time step then the previous stored time step will be used The flow field from this time step will be used as the steady state flow field by MODPATH 194 MIKE SHE Using MODPATH in the MIKE SHE GUI LAA Line item Comment End 01 02 1983 10 57 16 MODPATH will calculate particle locations until the end date or until all particles are removed by sinks StoringFrequency 0 5 The frequency for storing particle locations Years SinkStrength 0 1 Strength of sinks in MODPATH Must be between 0 and 1 1 all inflow to the cell are captured by sinks in the cell e g wells or other boundary conditions
81. of soil evaporation to tran spiration which in turn will influence the total actual evapotranspira tion possible under dry conditions Higher values of C will lead to smaller values of total actual evapotranspiration because more water will be extracted from the top node which subsequently dries out faster Therefore the total actual evapotranspiration will become sensi tive to the ability of the soil to draw water upwards via capillary action 66 MIKE SHE Land Use Se C C has not been evaluated experimentally Typically a value for C3 of 20 mm day is used which is somewhat higher than the value of 10 mm day proposed by Kristensen and Jensen 1975 C3 may depend on soil type and root density The more water released at low matrix potential and the greater the root density the higher should the value of C be Further discussion is given in Kristensen and Jensen 1975 Root Mass Distribution Parameter AROOT Water extraction by the roots for transpiration varies over the growing sea son In nature the exact root development is a complex process which depends on the climatic conditions and the moisture conditions in the soil Thus MIKE SHE allows for a root distribution determined by the root depth time varying and a general vertical root density distribution defined by AROOT see Figure 15 3 In the above dialogue AROOT is not time varying but can be specified as a time series using the ET Vegetation Proper
82. of solutes to the aquifer material surface by electrostatic forces called cation exchange If these processes occur sufficiently fast Technical Reference for Water Quality 351 LEA Reactive Transport Reference compared with the water flow velocity they can be described by an equi librium sorption isotherm Different equilibrium sorption isotherms have been identified from exper imental results with different sediments soils and rock types see for example Fetter 1993 MIKE SHE AD includes three of the most com monly applied isotherms namely the linear Freundlich and Langmuir equilibrium sorption isotherms Sorption processes that are slow compared with the water flow velocity must be described by a kinetic sorption isotherm In MIKE SHE AD the three equilibrium sorption isotherms have been extended to include a kinetically controlled sorption process so that a certain part of the sorbed matter is transferred to another part of the soil material 20 1 1 Equilibrium Sorption Isotherms The linear sorption isotherm is mathematically the simplest isotherm and can be described as a linear relationship between the amount of solute sorbed onto the soil material and the aqueous concentration of the solute c Kic 20 2 where K4 is known as the distribution coefficient The distribution coefficient is often related to the organic matter content of the soil by an experimentally determined parameter K c which can be
83. on a user specified sub set of the MIKE 11 river model called the coupling reaches The entire river system is always included in the hydraulic model but MIKE SHE will only exchange water with the coupling reaches Figure 14 1 shows part of a MIKE SHE model grid with the MIKE SHE river links the corresponding MIKE 11 coupling reaches and the MIKE 11 H points points where MIKE 11 calculates the water levels The location of each of MIKE SHE river link is determined from the co ordinates of the MIKE 11 river points where the river points include both digitised points and H points on the specified coupling reaches Since the MIKE SHE river links are located on the edges between grid cells the details of the MIKE 11 river geometry can be only partly included in MIKE SHE depending on the MIKE SHE grid size The more refined the MIKE SHE grid the more accurately the river network can be reproduced This also leads to the restriction that each MIKE SHE grid cell can only couple to one coupling reach per river link Thus if for example the dis tance between coupling reaches is smaller than half a grid cell you will probably receive an error as MIKE SHE tries to couple both coupling reaches to the same river link 228 MIKE SHE Coupling of MIKE SHE and MIKE 11 on If flooding is not allowed the MIKE 11 river levels at the H points are interpolated to the MIKE SHE river links where the exchange flows from overland flow and the
84. other words the particle tracking is calculated based on the flow field from one MIKE SHE time step MODPATH requires that the MIKE SHE result files include e head elevation in the saturated zone e groundwater flow in the x direction e groundwater flow in the y direction and e groundwater flow in the z direction MODPATH Output MODPATH outputs the standard output files as well as two shape files The point theme shape file projectname_point shp contains the particle locations at each storing time step plus the end point The line theme shape file projectname_line shp contains the path line for each particle calculated at each storing time step plus the end point MIKE SHE Editors 193 Se Particle Tracking Editor 9 1 Running MODPATH outside of MIKE SHE MODPATH can be run from the user interface or from a DOS command line or batch file If you are running the program from the command line you need to know about the following executables e ModPathDiagPFS exe The main executable e ModPathConv exe Handles the conversion between MIKE SHE and MODPATH e ModPath3 exe Standard USGS version of MODPATH The ModPathDiagPFS exe file is called using an ASCII input file using the pfs format The input file can be used as an argument when calling the executable If you do not include the file name as an argument then a browse dialogue will appear when you launch the executable Note the current set
85. polygon To move the entire polygon with the mouse inside the polygon left click on the polygon and while holding down the mouse drag the polygon around on the screen g Add Point To add a point to a selected polygon click on this icon and then left click on the polygon where you want to add a point A new point will be added on the line 4 Move Point To move a point in a selected polygon click on this icon then left on the point you want to move and drag the point to its new location while holding down the mouse Erase Point Polygon To erase a point in a selected polygon click on this icon and then click on the point that you want to delete To delete an entire polygon double click on the selected poly gon ab Add name to add or modify the name of a polygon click on this icon and then left click on the polygon A small dialogue will appear where you can change the name 202 MIKE SHE Data Analysis LAA 11 MIKE SHE TOOLBOX Grid series file compare 3 File Converter dfs2 dfs0 to dfs2 TO to dfs0 T2 to dfs2 3 8 util Grid Calculator Tool List Setup List The MIKE SHE tool box contains several wizard like tools with Next and Back buttons to move between dialogues In the first dialogue you specify a name for the setup If you save the setup then this name will be availa ble in the Toolbox menu allowing you to create custom set ups for your project The last Next butt
86. prediction The following sections first provide an overview of the linear reservoir theory followed by detailed descriptions of the implementation in MIKE SHE 17 2 1 Linear Reservoir Theory A linear reservoir is one whose storage is linearly related to the output by a storage constant with the dimension time also called a time constant as follows S kQ 17 30 where S is storage in the reservoir k is the time constant and Q is the out flow rate from the reservoir The concept of a linear reservoir was first introduced by Zoch 1934 1936 1937 in an analysis of the rainfall and runoff relationship Also a single linear reservoir is a special case of the Muskingum model Chow 1988 A Single Linear Reservoir with One Outlet The continuity equation for a single linear reservoir with one outlet can be written as I Q 17 31 where f is time and is the inflow rate to the reservoir Combining equation 17 8 and 17 9 yields a first order linear differen tial equation which can be solved explicitly dQ loyal a RAO z109 17 32 If the inflow I to the reservoir is assumed constant the outflow Q at the end of a time step dt can be calculated by the following expression dt k Qlt dt Ge 10 2 17 33 308 MIKE SHE Linear Reservoir Method a oe A Single Linear Reservoir with Two Outlets The outflows from a linear reservoir with two outlets can also be calcu lated explicitly
87. recharges the saturated zone The module is particularly useful for areas with a shallow ground water table such as swamps or wetlands areas where the actual evapotranspira tion rate is close to the potential rate In areas with deeper and drier unsaturated zones the model does not realistically represent the flow dynamics in the unsaturated zone The model only considers average con ditions and does not account for the relation between unsaturated hydrau lic conductivity and soil moisture content and thereby the ability of the soil to transport water to the roots The model simply assumes that if suffi cient water is available in the root zone the water will be available for evapotranspiration However it may be possible to calibrate the input parameters so that the model performs reasonably well under most condi tions The Simplified ET module includes the processes of interception pond ing and evapotranspiration While MIKE SHE s unsaturated zone module requires a detailed vertical discretisation of the soil profile unsaturated zone the Simplified ET module considers the entire unsaturated zone to be consist of two layers representing average conditions in the unsatu rated zone The input for the model includes the characterisation of the vegetation cover and the physical soil properties The vegetation is described in terms of leaf area index LAI and root depth The soil properties include a con stant infil
88. river level and the water table Ah in Layer 1 with Canyon option Zwt e J ZI Zriv VA Zbot 2 0 Ah Figure 17 3 Water table elevation versus the head difference using Eqs 14 2 14 3 and 14 7 Average steady state river conductance option In the steady state PCG solver the conductance used for the SZ river exchange in each iteration is averaged with the conductance of the previ ous iteration This is done to reduce the risk of numerical instabilities when the conditions are changing between flow no flow conditions in a computational cell It is recommended to use this option as it tends to enhance convergence Technical Reference for Water Movement 295 Se Saturated Flow Reference Steady state constant river water depth When running a steady state simulation that includes SZ river exchange a constant water depth may be specified for the river network which can be used to calculate the head gradient driving the exchange flow If a constant river water depth is not specified then the river water levels are determined in the following order 1 MIKE SHE hot start water level if MIKE SHE hot start is specified 2 Initial water levels from MIKE 11 if the MIKE 11 coupling is used 3 Water level equal to the river bed if not 1 or 2 i e dry river no flow from the river to the aquifer 17 1 3 Boundary Conditions The SZ module supports the following t
89. river net work e the full dynamic coupling of surface and sub surface flow processes in MIKE 11 and MIKE SHE This chapter describes only the interaction between MIKE 11 and MIKE SHE For technical information on MIKE 11 HD please refer to either the pdf version of the MIKE 11 HD Technical Reference Manual that is installed with MIKE 11 or the MIKE 11 documentation in the on line help Surface Water Aquifer Exchange Mechanisms In a catchment scale model it is usually sufficient to consider a river as a line located between model grid cells In this case the river aquifer exchange can be calculated inflow to and from both sides of the river depending on the head gradient to the adjacent groundwater cells The line assumption is generally valid if the river width is small relative to the model cells in other words catchment or basin scale models However very often a more precise description of the interactions between rivers flood plains aquifers and the atmosphere evapotranspira tion must be adopted In this context a reliable description of area inun dation and flood dynamics is crucial Thus the MIKE SHE MIKE 11 coupling considers three principally dif ferent surface water exchange mechanisms e River Aquifer Exchange line source link V 2 p 234 The river is located on the edge between two adjacent model grid cells The river is considered a line source sink to the groundwater and the river is a one way sink
90. saturated zone are calculated Main Branch Connection aa art Tributary i an MIKE 11 H Points MIKE SHE River Links Figure 14 1 MIKE 11 Branches and H points in a MIKE SHE Grid with River Links If flooding is allowed via Flood Codes then the water levels at the MIKE 11 H points are interpolated to specified MIKE SHE grid cells to deter mine if ponded water exists on the cell surface If ponded water exists then the unsaturated or saturated exchange flows are calculated based on the ponded water level above the cell If flooding is allowed via overbank spilling then the river water is allowed to spill onto the MIKE SHE model as overland flow In each case the calculated exchange flows are fed back to MIKE 11 as lateral inflow or outflow Technical Reference for Water Movement 229 a Channel Flow Reference 14 1 1 MIKE SHE Branches vs MIKE 11 Branches A MIKE 11 branch is a continuous river segment defined in MIKE 11 A MIKE 11 branch can be sub divided into several coupling reaches A MIKE SHE branch is an unbroken series of coupling reaches of one MIKE 11 branch One reason for dividing a MIKE 11 branch into several coupling reaches could be to define different riverbed leakage coefficients for different sec tions of the river If there are gaps between the specified coupling reaches the sub division will result in more than one MIKE SHE b
91. simulated in Figure 20 11 If plant uptake is included a concentration factor see Eq 20 18 is needed indicating to which extent solutes are taken up by the plants Fraction of moss recovery 1 0 0 8 0 6 0 08 Plant uptake Pliant uptake 0 00 re u YON 1994 Figure 20 11 Illustration of the effect of plant uptake on solute breakthrough Plant uptake was simulated with f 0 5 The early peak concentrations arise from macro pore transport and were almost alike in the two simulations Technical Reference for Water Quality 367 LAA Reactive Transport Reference 368 MIKE SHE User s Guide Governing equations a 21 PARTICLE TRACKING REFERENCE The MIKE SHE Particle Tracking PT module is an alternative descrip tion of solute transport PT calculates the location of a number of particles at every time step The particles are displaced individually in the three dimensional saturated groundwater zone SZ The movement of each particle is composed of a deterministic part where the particle is moved according to the local groundwater velocity calculated by the MIKE SHE and a stochastic part where the particle is moved randomly based on the local dispersion coefficients The PT module is a part of the MIKE SHE Advection Dispersion module and many of the same equations are used For example basically the same governing equation and the exchange of data with the MIKE SHE water mov
92. slower than the implicit SOR method because it usually requires much smaller time steps However it is generally more accurate than the SOR method and is often used to calcu late surface water flows during flooding Thus we recommend that you use the explicit method when overbank spilling from MIKE 11 to overland flow is allowed SOR parameters Maximum number of iterations If the maximum number of iterations is reached then simulation will go onto the next time step and a warning will be written to the simulation log file The default value is 200 itera tions which is normally reasonable You may want to increase this if you are consistently exceeding the maximum number of iterations and the residuals are slowly decreasing Increasing the following two residual values will make the solution con verge sooner but the solution may not be accurate However it may be such that only a couple of points outside your area of interest are dominat ing the convergence and inaccuracies in these points may be tolerable Decreasing these values will make the solution more accurate but the solution may not converge at very small values and it may take a long time to reach the solution If you decrease these values then you may also have to increase the maximum number of iterations 35 LEA Setup Data Tab Maximum head change per iteration If the difference in water level between iterations in any grid cell is greater than this amount then
93. sorption in the macro pores Pma 18 described by _ Beat Fa Oui ET O02 REl Pma Oma Gui Ps Jor F 4 one FF Fa o jor l15F lt 0 where F is the sorption bias factor p is the bulk mass Ona and 9 are the macro pore and the matrix porosity respectively The available bulk mass for sorption in the macropores is the remainder mass in the soil If F 0 the distribution of sorption sites between macro pores and matrix is assumed to be proportional to the distribution of porosities If F 1 sorp tion is assumed to occur in macro pores only and if F 1 sorption is only occurring in the matrix region The nature of Eq 20 11 is illustrated in Figure 20 3 Distribution of sorption sites E a T08 A a EAA A N cestode RE N EOLAS Sea seat nn ESEA 1e ul E S E EE ELS noe E E E E Maan E a 506 E E E ae a c AS 7 92 Le 0 1 0 5 0 05 1 Fb Figure 20 3 Illustration of the fraction of sorption sites located in the macro pore region Pma Pp as a function of F Mobile porosity 0 25 immobile porosity 0 05 Biological degradation radioactive decay or other kinds of attenuation of solutes can often be described as a first order degradation process with an 356 MIKE SHE User s Guide Decay a oa exponential decrease of concentration over a half life This is described in MIKE SHE as S 7e Maen U where upis the reference degradation rate coefficient calculated by 20 12 In
94. specific yield because the water released from storage comes primarily from the expansion of the water and aquifer com pression due to the reduction in water pressure increase in effective stress Thus the water released from storage is released from the entire column of water in the aquifer not just at the phreatic surface This results in a unit of L3 L3 L or 1 L The Specific Storage Coefficient is only used in transient simulations but must always be input Furthermore the specific storage coefficient is only 114 MIKE SHE Saturated Zone Se 2 16 14 Porosity used in the cells below the water table In the cells containing the water table the Specific Yield is used Porosity Conditions if the Include Advection Dispersion AD Water Qual ity option selected in the Simulation Specification dia logue dialogue Type Stationary Real Data EUM Data Unitse Porosity In a porous media most of the volume is taken up by soil particles and the actual area available for flow is much less than the nominal area This dis tinction is important when calculating flow velocities for solute transport The porosity is the cross sectional area available for flow divided by the nominal cross sectional area This is often referred to as the effective porosity since it discounts the dead end pore spaces that are not available for flow In the absences of dead end pores the porosity is equal to the specific yield The Por
95. the actual moisture content is the storage capacity of the unsaturated zone Vertical infiltration to the saturated zone will only occur when the water content is equal to Onax If the water table is below the ET extinction depth then a lower ET layer exists The moisture content of the lower ET layer is equal to the field capacity which is the minimum water content when ET does not exist 278 MIKE SHE Two Layer Water Balance oa The average moisture content of the upper ET layer can range between the field capacity Orc and the wilting point Owp which is the minimum water content at which the plants can remove water from the soil 16 3 2 Infiltration At the beginning of each computational time step rainfall first fills the interception storage If Zmay 1s exceeded the excess water is added to the amount of ponded water on the ground surface doc which is the height of surface ponding before infiltration is subtracted Next the maximum infiltration volume is limited by the rate of infiltra tion Thus Inf King At where Inf is the maximum amount of infiltration allowed during the time step due to the infiltration rate K pis the infiltration rate and At is the cal culation time step The maximum infiltration volume is also limited by the available storage volume in the unsaturated zone which is calculated by Inf Osat 8 _1 Zwt where 0 4 is the saturated water content O is the water content a
96. the geologic layers calculation layers and screened intervals for the well The topography is shown if the Level is less than the topography EUM Data Units Elevation Depth The Depth is defined from the Level It defines the maximum depth shown on the graphical view displaying the profile view of the geologic layers calculation layers and screened intervals for the well The bottom of the geologic layers is shown if the Level minus the Depth is higher than the bottom of the geologic layers EUM Data Units Depth below ground 168 MIKE SHE Ss Well Field The Well Field item is used for filtering the displayed bore holes The Mask item in the top menu bar uses the Well Field for it selection criteria 5 0 3 Well Filters axles Filter and pumping definition of selected well Pumping file 11 97 V C5 Testing fyn abs 7lag suf_dm 15 55 1 00 Top This is the elevation of the top of the screen or open hole interval for the well in the same units ft m etc as specified in the EUM Data base for item geometry 2 dimensional Bottom The elevation of the bottom of the screen or open hole interval for the well in same units ft m etc as specified in the EUM Data base for item geometry 2 dimensional Pumping File Name of the dfs0 file with groundwater pumping data for the well When using the Browse button to select the file you will be given the option of specifying the
97. the radius specifies the radius of the circle The radius should normally be greater than the cell size Other wise all of the particles could be located in the same cell which will not give you a realistic well capture zone Number of particles This is the number of particles along the line or around the circle The particles are evenly distributed along the line or cir cumfrence Import An set of single particles can be imported to the table using either an ASCII text file or a point theme shape file The ASCII text file must be space delimited with the following fields without a header X_coord Y_coord Depth Layer The shape file must be defined as a point theme with either a Depth or Layer attribute If both are defined then both will be imported but the Layer option will control Results Tab In the Results tab a data item is created for each of the Particle Tracking Simulations specified in the Simulation Tab V 2 p 197 MODPATH Results MODPATH generates a number of files which are described in the MOD PATH documentation In addition to the standard files we have modified the MODPATH code to also output two shape files a point theme file with all of the particle locations at every save time and a line theme file with all of the path lines The map view adds these two shape files to the other overlays defined in the Display V 2 p 196 dialogue 200 MIKE SHE Results Tab 10 SIMPLE SHAPE EDITOR
98. the soil database in which the soil definition is available The Edit button opens the specified Soil property database file whereas the Browse button opens the file browser to select a file Vertical discretisation In this section you specify the vertical discretisa tion of the soil profile which typically contains small cells near the ground surface and increasing cell thickness with depth However the soil properties are averaged if the cell boundaries and the soil bounda ries do not align From and To Depths refers to the distances to the top and bottom of the soil layer below the ground surface Neither are directly edit able since they are calculated from the number of cells and their thicknesses Cell Height is the thickness of the numerical cells in the soil pro file No of Cells is the number of cells with the specified cell height Together these two values define the total thickness of the current section The discretisation should be tailored to the profile description and the required accuracy of the simulation If the full Richards equation is used the vertical discretisation may vary from 1 5 cm in the uppermost grid points to 10 50 cm in the bottom of the profile For the Gravity 94 MIKE SHE Unsaturated Zone LEA Flow module a coarser discretisation may be used For example 10 25 cm in the upper part of the soil profile and up to 50 100 cm in the lower part of the profile Note that at the
99. this case more than one reservoir can be specified In low areas adjacent to the river branches the water table may in periods be located above or immediately below the surface In this case it will contribute more to total catchment evaporation than the rest of the area To strengthen this mechanism water held in the part of the baseflow reser 310 MIKE SHE Linear Reservoir Method a os m ame SUBCATCHMENT BOUNDARY ae aes TOPOGRAPHICAL ZONE Figure 17 9 Example of Desegregation of a Catchment into Sub catchments and Topographical Zones voirs beneath the lowest interflow zone may be allowed to contribute to the root zone when the soil moisture is below field capacity Previous experience with lumped conceptual models shows that the linear reservoir approach is sufficient for an accurate simulation of the interflow and baseflow components if the input to the reservoirs can be assessed correctly and the time constants of the outlets are known Due to the dis tributed approach and physically based representation used in MIKE SHE in the overland and unsaturated zone flow components an accurate simu lation of soil moisture drainage in space and time is provided in MIKE SHE for the linear reservoir module The time constants on the other hand are basically unknown for an ungauged catchment but a fair estimate may be obtained from an evaluation of the hydrogeologic conditions and or from gauged catchment with similar subs
100. to the time increment The vertical grid system for a soil column is shown in Figure 16 1 Similar to Eq 16 8 the discrete form of Eq 16 1 gives n 1 n n 1 n l aI VI OYI opran Woe YI cy te priy H At AZ 43 l 16 9 ytt u AAZ 1 AZ K 4 JoHa AZ n 1 S7 The soil property K is centred in space using the arithmetic mean Kitt Ky 2 n n V Kyt e Kit Kut J 2 n Kjt 264 MIKE SHE Richards Equation a oe iPERMEAGLE ED Figure 16 1 Vertical Discretisation in the Unsaturated Zone Eq 16 9 involves three unknown values at time n and one known value at time n for each node Written for all nodes with reference to Technical Reference for Water Movement 265 Se Unsaturated Flow Reference Figure 16 1 a system of N M equations with N M unknowns is obtained The system of equations forms a tri diagonal matrix The J te row in the matrix is Yy Dy Wn 1 Dy Ap ow eee dy TED Gu 1 Busi Am 1 Vm 1 Dy i Gy By vu Dm Apt wy t Bet y Git wry D 16 11 where Crt At Ki Cat Ayn At n l n l We By Wei t Fy AZ K8z 1 AZ y 16 12 2 n l YA AZ AZ PAZ AZ 1 AZ WAZ AZ AZ The solution to the matrix system Eq 16 10 is solved by Gaussian elimi nation Assuming that y and w can be related in the following recurrence relation 16 13 266
101. unsaturated flow calculated beneath the river 14 2 2 River bed only conductance If there is a river bed lining then there will be a head loss across the lin ing In this case the conductance is a function of both the aquifer conduc tivity and the conductivity of the river bed However when the head loss across the river bed is much greater than the head loss in the aquifer mate rial then the head loss in the aquifer can be ignored e g if the bed mate Technical Reference for Water Movement 235 Channel Flow Reference rial is thick and very fine and the aquifer material is coarse This is the assumption used in many groundwater models such as MODFLOW In this case referring to Figure 14 2 the conductance C between the grid node and the river link is given by C L w dx 14 5 where dx is the grid size used in the SZ component L is the leakage coef ficient 1 T of the bed material and w is the wetted perimeter of the cross section In Eq 14 5 the wetted perimeter w is assumed to be equal to the sum of the vertical and horizontal areas available for exchange flow From Figure 14 2 this is equal to da l respectively The horizontal infiltra tion length is calculated based on the depth of water in the river and the geometry of the triangular river link cross section The infiltration area of the river link closely approximates the infiltration area of natural channels when the river is w
102. vertical flow condition a confined conditions in nodes i andj b unconfined condition in node i c unconfined in nodes i andj d dry conditions in node j and confined conditions in node i Relaxation Coefficient The relaxation coefficient w is used in the solution scheme to amplify the change in the dependent variable hydraulic head h during the iteration The value of w should be less than 2 to ensure convergence but larger than 1 to accelerate the convergence 304 MIKE SHE 3D Finite Difference Method a oe The optimal value is the value for which the minimum number of itera tions are required to obtain the desired tolerance It is a complex function of the geometry of the grid and aquifer properties Figure 17 7 illustrates the relation between w and the number of iterations for a given grid In practice the optimal value of w can be found after setting up the grid The model is run for a few time steps e g ten with a range of w values between 1 and 2 and the total number of iterations is plotted for each run against the w value as shown in Figure 17 7 The minimum number of iterations corresponds to the optimal value of w No of iterations 1 0 Optimal 2 0 value Figure 17 7 Empirically relationship between the relaxation coefficient w and number of iterations for a given model Maximum Residual Error The maximum residual error is the largest allowable value of residual error during an itera
103. you can specify the iteration stop criteria and the maximum water balance error in addition to the max imum number of iterations Maximum profile water balance error The tolerance criteria in the UZ SZ coupling procedure is the maximum allowed accumulated water balance error in one UZ column If this value is exceeded the location of the groundwater table will be adjusted and additional computations in the UZ component will be done until this criteria is met The recom 39 LEA Setup Data Tab mended value is 0 002m or less Since the Two Layer Water Balance method does not calculate a water table per se this parameter is only used in the Richards Equation method and the Gravity Flow module Iteration Stop Criteria The solution is deemed to have converged when the difference in pressure head between iterations for all nodes is less than or equal to the iteration stop criteria The recommended value is 0 02m or less Maximum water balance error in one node This is defined as the frac tion of the total saturated volume in the node the time step will auto matically be reduced if the error is exceeded The recommended value is 0 01 or less with a value of 0 001 to 0 002 m being reasonable 2 2 6 SZ Computational Control Parameters Solver Type ditioned Conjugate Gradient Steady State C Successive Overrelaxation Package SOR SZ Computational Control Parameters Conditions if Saturated Flow specified in
104. 0 particles are not captured PathDir 0 EndSect MODPATH_Parameters 0 forward tracking Particle tracking direction 1 backward tracking Initial particle locations The initial particle locations can be defined by either a space delimited ASCII text file or a GIS shape file An ASCII text file must have the following format X coordinate Y coordinate Layer Pos where the X and Y coordinates are in the same model coordinates as the flow model the Layer is the numerical layer number of the model start ing with 1 at the top and the Pos is the relative vertical position in the layer with 1 meaning that the particle is at the top of the layer and 0 mean ing that the particle is at the bottom of the layer A GIS shape file must contain a Layer field and a Pos field where these have the same meaning as in the ASCII file 9 2 Using MODPATH in the MIKE SHE GUI The MODPATH user interface is opened by selecting New File in the top menu or by clicking on the New icon in the icon bar and then select ing MShe Particle Tracking trpt from the MIKE SHE document list The MIKE SHE Particle Tracking user interface follows the same format as the other MIKE Zero user interfaces with three tabs a Setup Tab a Simulation Tab and a Results Tab MIKE SHE Editors 195 Sex Particle Tracking Editor 9 3 Setup Tab The Setup tab is used to define the basic file information for MODPATH including the overla
105. 0 2 31 23 59 0 24 0 24 0 24 0 24 0 24 When you select this option a file selection dialogue appears where you can select the t0 file If the file is properly prepared then the import should proceed automatically What data is imported For each well in the t0 file a well is added to the list of wells including the well name and the x and y coordinates of the well The time series information for each well is read and a separate dfs0 file is created for each of the wells in the t0 file These dfsO files are placed in a subdirectory that has the same name as the t0 file Importing layer information The layer information can only imported if the well editor file is open at the same time as a model file SHE file that has previously been pre processed In this case the t0 import utility reads the pre processed model layer information and sets the top and bottom of the filter to the top and bottom of the specified layer in the t0 file MIKE SHE Editors 171 Well editor 5 1 2 Note This import function may not create a well file that generates identi cal results to pre 2002 versions of MIKE SHE if the model geometry is modified layer elevations no longer are identical or if wells were defined as line sinks Errors and warnings Since the t0 import utility uses FORTRAN list directed read statements any missing information in the header will cause the import to fail How ever the import utility does not i
106. 000 292 R Storing Time Steps 33 Redistribution of ponded water 224 Subcatchments oi 224 se ea eds 54 Relaxation Coefficient Sublimation 244 255 SOR ortada 40 pe oe Peon 304 Successive Overrelaxation 301 Results 155 Surface Depth Storage 6 64d bee amp eee Hs 135 ET sansu piora he ee 100 384 MIKE Zero Index Surface Drainage 123 T Time Series 156 Time series output 138 Time Step Control 30 Topography 56 Two Layer Water Balance 275 Simplified ET 254 U Unsaturated Flow 261 Unsaturated Zone 90 El toc 4026 hte tee goo 260 Upper Level 111 UZ Classification 96 UZ Coupling 2424042402484 44 317 UZ SZ Coupling Evaluation 287 V Van Genuchten 174 176 Vegetation 64 Development Table 180 Properties 64 177 Stages 178 WwW Water Application 74 Water balance correction 216 Water Depth Initial 85 Well Database Overlays 25 Well editor 167 Well Filters 169 Well Locations 168 Wells Layers 170 Y Melde gane dae E a ees es ee Gos 114 385 a oe Index 386 MIKE Zero
107. 1 jk 1 1 y P jk 1 i Figure 19 3 Control volume defining an internal SZ grid 334 MIKE SHE User s Guide Solute Transport in the Saturated Zone ao For the control volume shown in Figure 19 3 this equation is written in finite difference form as wei x CIRIT Cik T Ox PAATE TA aes plasen Ty C ktes 2 CUR Pes HEE leinen ciun 0 19 11 where n denotes the time index In Eq 19 11 ox and are the directional Courant numbers defined Vy dt _ Vy dt _ Vy dt Ay 7 Az 19 12 and the c terms are the concentrations at the surface of the control vol ume at time n As these terms are not located at nodal points they have to be interpolated from known concentration values CHAR O13 t Cini T Vici ciren T bici 19 13 The concentration c is the concentration around the actual point for example j k 1 1 and the weights 6 y and p are determined in such a way that the scheme becomes third order accurate The determination of the weights is demonstrated in Vested et al 1992 and their values are listed in Table 19 2 A number of 8 weights has proven to be an adequate choice and their loca tion for the determination of the c is shown in Figure 19 4 The other boundary concentrations are found in a similar way Technical Reference for Water Quality 335 Advection Dispersion Reference Table 19 2 Weight functions for advective trans
108. 1 H point volumes Figure 14 3 Sharing of MIKE 11 H point volumes with MIKE SHE river links The water levels and flows at all MIKE 11 H points located within the coupling reaches can be retrieved from the MIKE SHE result file How ever since the MIKE 11 flows are not used by MIKE SHE the river flows stored in the MIKE SHE result file are not the flows calculated at the MIKE 11 Storing Q points Rather the flows stored in the MIKE SHE result file are the estimated flows at the MIKE 11 H points That is the flows in the MIKE SHE result file have been linearly interpolated from the calculated flows at the Storing Q point locations to the H point loca tions on either side of the Storing Q point If the exact Q point discharges are needed they must be retrieved or plotted directly from the MIKE 11 result file Technical Reference for Water Movement 233 a Channel Flow Reference 14 2 River Aquifer Exchange line source link The exchange flow Q between a saturated zone grid cell and the river link is calculated as a conductance C multiplied by the head difference between the river and the grid cell Q C Ah 14 1 Note that Eq 14 1 is calculated twice once for each cell on either side of the river link This allows for different flow to either side of the river if there is a groundwater head gradient across the river or if the aquifer properties are different Referring to Figure 14 2 the head diffe
109. 1 p 52 2 16 7 Upper Level Upper Level dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground The Upper Level is the upper elevation of the lense It is used by the inter polation algorithm to assign geological properties to the model cells Related Items e Working with Lenses V p 52 2 16 8 Horizontal Extent Horizontal Extent dialogue Type Integer Grid Codes EUM Data Units Grid Code The horizontal extent is used to define the lateral extents of geologic lenses The horizontal extents is usually a shp file polygon or a dfs2 grid 111 Setup Data Tab file In either case the polygon name or the dfs2 codes are ignored Any cell within a polygon or with a grid code different than 0 is treated as part of the lense Related Items e Working with Lenses VJ p 52 2 16 9 Geological Unit Distribution Geological Unit Distribution Conditions If geology defined by Geologic Units dialogue Type Integer Grid Codes EUM Data Units Grid Code Valid Values each value must be in the Geological Units table The Geological Unit Distribution references the geological units defined in the table Each Integer Code must refer to one of the geological units in the table Related Items e Geological Units V2 p 108 e Working with Lenses VJ p 52 2 16 10 Horizontal Hydraulic Conductivity Horizontal Hydraulic Conductivity dialogue Type Stationa
110. 11 cross section the elevation of Marker 2 in the cross section The top of the river link equals the elevation of highest bank elevation left or right bank marker See Figure 14 2 Technical Reference for Water Movement 231 a Channel Flow Reference 4 link MIKE 11 river level i width gt i lt MIKE 11 cross section v V MIKE SHE groundwater level MIKE SHE MIKE SHE river link cross section groundwater node Figure 14 2 A typical simplified MIKE SHE river link cross section compared to the equivalent MIKE 11 cross section If the MIKE 11 cross section is wider than the MIKE SHE cell size then the river link cross section is reduced to the cell width This is a very important limitation as it embodies the assumption that the river is nar rower than the MIKE SHE cell width If your river is wider than a cell width and you want to simulate water on the flood plain then you will need to use either the Area Inundation using Flood Codes areal source sink V 2 p 239 option or the Direct Overbank Spilling to and from MIKE 11 V 2 p 240 option If you don t want to simulate flooding then the reduction of the river link width to the cell width will not likely cause a problem as MIKE SHE assumes that the primary exchange between the river and the aquifer takes place through the river banks For more detail on the river aquifer exchange see River Aquifer Exchange line source lin
111. 13 11 Ax 214 MIKE SHE Finite Difference Method a oe where I idx 13 12 ZO Oyv O5 Ort Qw and where i is the net input to overland flow in Eq 13 1 and the Q s are the flows into the square across its north south east and west boundaries evaluated at time t Now consider the flow across any boundary between squares see Figure 13 2 where Zy and Zp are the higher and lower of the two water levels referred to datum Let the depth of water in the square correspond ing to Zy be hy and that in the square corresponding to Zp to hp Figure 13 2 Overland flow across grid square boundary Equations 13 8a and 13 8b may be used to estimate the flow Q between grid squares by KAx Q ay Zp h 13 13 where K is the appropriate Strickler coefficient and the water depth h is the depth of water that can freely flow into the next cell This depth is equal to the actual water depth minus detention storage since detention storage is ponded water that is trapped in shallow surface depressions Equation 13 13 also implies that the overland flow into the cell will be zero if the upstream depth is zero The flow across open boundaries at the edge of the model is also calculated with Eq 13 13 using the specified boundary water levels Technical Reference for Water Movement 215 a Overland Flow Reference 13 1 3 Successive Over Relaxation SOR Numerical Solution The m
112. 2 Example database aaau aa Re Dee we 183 WATER BALANCE EDITOR 2222 c 0444888 05 44 048282424 185 8 1 EXVACHONM 2 4 es si oe amama iw ew ee ed amp ded eee ee Gee 186 8 2 PostprocessingS lt 2 2 62 a440ebiwdes du oa eu eaku Gad 187 8 2 1 Postprocessing Detail 188 Go Res hS lt iaai ei ion a E he AP ee ee Se 190 PARTICLE TRACKING EDITOR 2 2 000002 4b ke a 193 9 1 Running MODPATH outside of MIKE SHE 194 9 2 Using MODPATH inthe MIKE SHE GUI 195 9 3 Sep 40 oacteku Bee e he beet eG Bees Bee a ee eee 196 93A DISDIBY cue eae ea bre ee hea dee Ee ew de ee Be 196 9 3 2 Flow model seup 2 26 2 5 24 phe edhe ee weeue 196 9 4 Simulation TaD 2c t22 e8cannhe GG bh dA SHC EE YES EMER 197 9 4 1 Transport Simulations 0084 197 9 4 2 MODPATH simulation specification 198 949 PaniCles 44 0 4 auei ves eal oa ee ee OE hale ew BSR 199 9 5 AGSUNG Tab s a cma meaa aa Se a a ee OB ree ee eee ee a 200 Se 10 SIMPLESHAPEEDITOR 2 000 201 11 MIKE SHE TOOLBOX 0 0 0 0 2000000000000 022 ee 203 11 1 Data Analysis a2 ec ead Se Reed ee eee en GE Ow Oe Se SSS 203 11 1 1 Grid series file compare 22 c eee de wee ee ee ewe 203 112 File Converter sausi eos kd eee ed ne of ed a eed de Jeo ee Koa oe Gene 204 11 2 1 dfs2 dfs0 to dfs2 Gud dw th bv hh eh ht amp eS 204 11 2 2 tO to dfs0 and t2 to dfs2
113. 20 amp Mo 594593 6 13035e 0 35 C 5 Testing Kalibreringspej 1 2 l 588873 6 1286e 00 54 Vv C5 Testing Kalibreringspej a 4 589597 6 12972e 0 21 IV C 6Testing Kalibreringspej e conet7 c4agndatarn aT EN re CAD Taatinal Walilenvinaansi The Detailed time series output dialogue allows you to specify the loca tion at which you want detailed time series output and the item that you want output For each specified point the output variable is stored in a dfsO file with one value for every simulation time step Finally for each item in the detailed time series table an HTML plot is created in the Result Tab C5 Testing Kalibreringspej Note All of the detailed time series items are stored in one dfs0 file This can lead to file size and disk space errors if you have a long detailed sim ulation or more than 200 detailed time series items Also the HTML out put in the Results Tab will become very slow if you have a lot of items since it has to read the entire dfsO file and generate all of the graphs every time you access the Detailed Time Series page in the Results Tab Name This is a text field that can be used to specify a reference name for the location for example a borehole name This is also the name that will be used for the time series item in the Dfs0 file created during the simulation Data Type This is the list of available output items is dynamic in the sense that the
114. 43 LEA Setup Data Tab Related Items e Time Step Control V 2 p 30 e Detailed time series output V 2 p 138 e Detailed MIKE 11 Output V 2 p 141 e Gridded Data Results Viewer V 2 p 157 2 19 Extra Parameters The Extra Parameters Section is available to support new features in MIKE SHE that are not yet supported in the dialogues and data tree Detailed descriptions of the features that use Extra Parameters are found in Extra Parameters V 1 p 145 If you need to activate a feature that is only supported in the Extra Param eters section you must first add the necessary number of lines to the Extra Parameters table Then fill in the data that is required for the module Name this is the name of the parameter that is required by the unsup ported feature It must be spelled exactly as specified in the documen tation In may be the actual name of the feature or the name of a parameter Type The type is the type of parameter The following types are availa ble Float Real floating point number Integer Integer number Boolean an On Off checkbox typically used to turn a feature on or off Text a character string file name this is typically the file where more detailed input data is recorded Value this is the value associated with the Type above 144 MIKE SHE Extra Parameters oe 3 PREPROCESSED DATA TAB MIKE SHE Flow Model Description Processed data GeoScene3D _Se
115. 5 LEA Setup Data Tab 2 10 4 Sheet Application Area Sheet Application Area Conditions Irrigation selected in Land Use and UZ and ET simu lated and Sheet selected as an application method dialogue Type Integer Grid Codes EUM Data Units Grid Code The sheet application area is used to define where the sheet irrigation must be applied The program does not make any distinction between sheet application areas The sheet irrigation will be distributed on every cell with a non delete value or non zero integer code within the command area 2 10 5 Irrigation Demand v Ref moisture content Saturated kd ID Global Temporal Distribution Constat x Moisture deficit start jo Moisture deficit end 0 Demand type i Irrigation Demand Conditions Irrigation selected in Land Use and UZ and ET simu lated dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The Irrigation Demand is used to describe when the water will be applied in the model The Irrigation Demand data item is divided into two dialogues The first is the distribution dialogue for the Demand Areas and the second contains the information on when the water will be applied in each Demand area 76 MIKE SHE Land Use Ss Demand Type User Specified For the User Specified demand type the demand is not calculated Rather it is simply specified as a constant value or as a time series Cr
116. 5 O41 0 Field Capacity 0 0 0 7 295 01l 0 Field Capacity 0 0 D 8 365 0 4 0 Field Capacity 0 0 0 you must specify a value for each of these demand types Although those that will not by used may be left at the default values Maximum allowed deficit If irrigation is handled automatically based on the actual moisture content in the soil the soil moisture deficits are the deficits at which irrigation is going to start and stop The soil mois ture deficit is defined relative to the plant available water content in the root zone which is the difference between a reference moisture content and the moisture content at wilting point If for example the reference moisture content is the moisture content at field capacity and irrigation should start when 60 of the available water in the root zone is used and cease when field capacity is reached the value in the start column should be 0 6 the value in the stop column should be 0 and the refer ence input should be field capacity User specified Alternatively the irrigation amount applied in each crop stage can simply be prescribed Crop stress factor The crop stress factor is the minimum allowed frac tion of the reference ET that the actual ET is allowed to drop to before irrigation starts That is the minimum allowed Actual ET Reference ET relationship This should be a value between 1 and 0 Ponding depth When using this option the demand will be equal to the differen
117. 500 gt 459310 gt 20 gt 1 gt time obsdata gt 3 Related Items e Time Step Control V 2 p 30 e Detailed MIKE 11 Output V 2 p 141 140 MIKE SHE Storing of Results ao e Grid series output V2 p 143 e MIKE SHE Detailed Time Series V 2 p 156 2 18 2 Detailed MIKE 11 Output paa nxs E Data type Branch name Chainage Obs Obs Data Filename Rhein at Koln Water Level Rhein main 134560 M C 5 Testing TS1 dfs0 Rhein at Bonn Discharge _y Rhein main 156740 ss C5 Testing TS1 dfs The Detailed time series output for MIKE 11 allows you to specify the river chainage location at which you want detailed time series output and the item that you want output For each specified point the output variable is stored in a dfsO file with one value for every simulation time step Finally for each item in the detailed time series table an HTML plot is created in the Result Tab with or without observation data The principle advantage of this option is that you can now easily create calibration plots of calculated versus observed water levels without open ing and having to create specific plots in MIKE View Name This is a text field that can be used to specify a reference name for the location for example a gage name Data Type This is the list of available output items which for MIKE 11 only contains two items water level and flow rate Branch name the Branch name must be a valid branch name i
118. 6 MIKE SHE River Aquifer Exchange line source link a oe This formulation for da assumes that the river aquifer exchange is prima rily via the river banks which is consistent with the limitation that there is no unsaturated flow calculated beneath the river 14 2 3 Both aquifer and river bed conductance If there is a river bed lining then there will be a head loss across the lin ing In this case the conductance is a function of both the aquifer conduc tivity and the conductivity of the river bed and can be calculated as a serial connection of the individual conductances Thus referring to Figure 14 2 the conductance C between the grid node and the river link is given by 1 Co 14 6 K da dx L w dx where K is the horizontal hydraulic conductivity in the grid cell da is the vertical surface available for exchange flow dx is the grid size used in the SZ component ds is the average flow length Le is the leakage coefficient 1 T of the bed material and w is the wetted perimeter of the cross sec tion The average flow length ds is the distance from the grid node to the middle of the river bank in the triangular river link cross section ds is limited to between 1 2 and 1 4 of a cell width since the maximum river link width is one cell width half cell width per side In Eq 14 5 the wetted perimeter w is assumed to be equal to the sum of the vertical and horizontal areas available for exchange flow From
119. 8 63 oa Setup Data Tab 2 10 1 Vegetation Spatial Data Type Station based v Grid codes dfs2 7 ET parameters Station Based Distribution File C 5 Testing NRSaby MAPS landuse_DAISY dis2 al Edit meter landuse daisy che iilik Sian a a th ee ih fi 6138000 6136000 6134000 Vegetation Conditions If Evapotranspiration selected in the Simulation Speci fication dialogue EUM Data Units Grid Code Time Series EUM Data Leaf Area Index and Units Root Depth or Vegetation Property File see ET Vegetation Properties Editor V2 p 177 dialogue Type Special version of Time varying Real Data The main Vegetation dialogue is used to define the distribution of vegeta tion across your model area It works the same as any other dialogue for Grid Codes with associated time series data In this case however there are two relevant time series parameters the Leaf Area Index and the Root Depth Both of these parameters can be defined as constants via dfsO files or they can be defined from a Vegetation Properties file Note The crop coefficient K is only available in the Vegetation Proper ties file Using a Vegetation Properties file The Vegetation Properties file typically contains a time series of the root depth and leaf area index for either one year or for the growing season If you are using a properties file then you have to specify the crop develop ment schedule
120. Actual 3 lt n 2 ee a GARR Sb ee 260 Gravity Flow iw eb ose a ee 275 Canopy 259 Initial conditions Ponded Water 259 3DFinite Difference Method 271 Saturated Zone 260 initial conditions Unsaturated Zone 260 saturated zone 300 Evapotranspiration 79 243 258 Initial Potential Head 117 Lakes 45 Baie a Se he Ree bs 80 Interactive Map 167 202 Parameters 179 Interflow calculation 313 Evapotranspiration Parameters 65 Interflow Percolation 315 Exchange Flows 239 Interflow Reservoirs 105 Exchange Mechanisms Irrigation Surface Water Aquifer 227 Demand sa k oa i oe he eS 76 Extra Parameters 144 Parameters 181 Priorities 78 F Irrigation Command Areas 69 Finite Difference 214 Water Source Types 70 Finite Difference Method 211 Water Source Types External 74 Flood codes kaw amp ed wR eS Ke 81 Water Source Types River 71 Flooded Area 239 Water Source Types Shallow Well FlowstoMIKESHE 232 73 Water Source Types Single Well 72 G Geological Layers 109 K Geological Lenses 110 Kristensen and Jensen method 244 Geological Units 108 Gradual activation of SZ drainage 293 L Gravity Flow 273 Land Use 6 od oe eee RAR wo 62 Grid series Leak
121. Air Temperature Air Temperature Conditions if Snowmelt selected dialogue Type Time varying Real Data EUM Data Units Grid Code Time Series EUM Data Temperature Instantaneous Units This is the temperature in Celsius that is used to calculate the amount of snow that melts per time step 60 MIKE SHE Precipitation Ss Snowmelt If the air temperature is above the Threshold melting temperature see Snowmelt Constants then the snow will begin to melt The snow storage will be reduced by Isnow Degree_day_factor Air_temp Threshold_temp At 2 4 where the Degree day factor and the Threshold Temperature are defined in the Snowmelt Constants dialogue and Af the length of the UZ ET time step Snow storage will be reduced to zero if snow 18s greater than the snow storage If the air temperature is below the Threshold melting temperature then the ET module will remove water from the snow storage as sublimation before any other ET is removed using E snow Reference_ET At 2 5 where Reference_ET refers to the Reference Evapotranspiration before being reduce by the Crop Coefficient k that is specified in the Vegetation Development Table V 2 p 180 If there is not enough snow storage then FE snow Will reduce the snow storage to zero Air temperature must be instantaneous values Thus for air temperature time series an average air temperature is used in each time step based on a linear interpolati
122. Data Tab 2 10 2 Paved Runoff Coefficient Paved Runoff Coefficient Conditions If Overland Flow selected in the Simulation Specifica tion dialogue and Paved Areas selected in Land Use dialogue dialogue Type Stationary Real Data EUM Data Units Fraction The Paved Runoff Coefficient defines the fraction of overland flow that drains to storm sewers and other surface drainage features in paved areas The Paved Runoff Coefficient acts in two ways 1 it tells MIKE SHE where there is paving and 2 the value specifies how much of the overland flow is allowed to infil trate and how much should be drained away Thus in non paved cells you should use a value of zero or an Undefined Value 1e 35 Whereas in paved cells you must specify a value between 0 and 1 The coefficient value defines the fraction of the overland flow that will be drained via the SZ drainage network in the current time step However the water is not added to the water in the drains but rather it is sent directly to the boundary specified via the SZ drainage network For example most rainfall on a paved surface is drained to storm sewers and the storm sewers typically drain directly in a river or stream Thus if 25 of your land area is paved then a paved runoff coefficient of 0 25 will remove 25 of the overland flow and send it directly to the river link specified for the local SZ drainage network The remaining 75 will be available for infiltrat
123. Default value is checked then the global values defined in the main vegetation dialogue shown below will be used Distribution type Data type ET parameters zl Global sz LAI Timeseries file mj Eat el eee RD Timeseries file If the default value is unchecked then you can specify the ET parameters by vegetation type Vegetation stages _ ___Stagename tnd aay The first thing to do is to specify the standard vegetation stages for each crop in the database These temporal variations in vegetation characteris tics can normally be described by a number of characteristic stages of spe cific length The changes are defined as a set of linear changes between two consecutive crop stages Three parameters describe the stage the leaf area index LAI the root depth RD and the crop coefficient K 178 MIKE SHE Vegetation Database Items on The day number indicates the cumulative days from crop establishment e g sowing to the end of the specific crop stage If in the Vegetation V2 p 64 dialogue subsequent start dates overlap with the development cycle a warning will be issued in the log file that says the crop development was not over yet before the new crop was started MIKE SHE will then start a new crop cycle at the new start date 7 1 3 Evapotranspiration Parameters The parameters used in the evapotranspiration calculations can be divided into thre
124. E Editors 167 Well editor 5 0 2 The overlays are automatically carried over from the model Setup Tab You can t add or modify overlays directly in the Well Editor This must be down from the Setup Tab Right clicking on the map allows you to control the zoom and a number of other functions Grid turns on off a faint coordinate grid that changes with the zoom fac tor Set new area coordinates allows you to change the displayed area of the map Text turns on off the display of the Well ID labels for the wells Export Graphic allows you to save the view to the clipboard or a bmp or wmf graphic file for importing into MSWord for example Well Locations Well locations x Level Depth Well Field in 583679 00 6125678 00 amp 0 00 0 00 modelomrad 425 M 42 2000 579720 00 6117702 00 B 0 00 0 00 Undefined 425 M 42 2000 583040 00 6116387 00 amp 0 00 0 00 Undefined 425 M 42 2000 579181 00 6124624 00 amp 0 00 0 00 Undefined 427 F 07 103 598656 00 6108707 00 0 00 0 00 Undefined 6 427 M 42 1000 596254 00 6109889 00 amp 0 00 0 00 Undefined F 47h41 nnn sa77snnn Banka NN A I ann NNN lt indetined Well_ID This is the user specified name of the well The Well_ID cannot contain any spaces X Y These are the X and Y map coordinates of the well EUM Data Units Item geometry 2 dimensional Level The Level defines the maximum elevation shown on the profile view of
125. E SHE Evapotranspiration Se 2 11 2 11 1 example if there is a demand for 100 m3 of water in 10 cells but only 50 m is available and 5 of the cells have a demand of 15 m3 while 5 have a demand of only 5 m3 then the first cells will receive 7 5 m3 while the latter will receive only 2 5 m3 Evapotranspiration Reference There are no options on the Evapotranspiration main dialogue and only one item in the data tree reference evapotranspiration Evapotranspiration Reference Evapotranspiration dialogue Type Time varying Real Data EUM Data Grid Code Units Time Series Evapotranspiration Rate EUM Data Units The reference evapotranspiration ET is the rate of ET from a reference surface with an unlimited amount of water Based on the FAO guidelines the reference surface is a hypothetical grass surface with specific charac teristics The reference ET value is independent of everything but climate and can be calculated from weather data The FAO Penman Monteith method is recommended for determining the reference ET value The Reference Evapotranspiration item comprises both a distribution and a value The distribution can be either uniform station based or fully dis tributed If the data is station based then for each station a sub item will appear where you can enter the time series of values for the station 79 LEA Setup Data Tab 2 12 Rivers and Lakes River Simulation File SIM11 _ C
126. EDITOR The water balance utility is a flexible post processing tool for generating water balance data for MIKE SHE simulations Output from the water bal ance utility can include area normalized flows storage depths storage changes and model errors resulting from convergence problems Water balance data can be generated at a variety of spatial and temporal scales and in a number of different formats To extract the water balance data you must specify which simulation you are going then specify the area of your model that you want the water bal ance for and finally extract the MIKE SHE water balance data from the results files Once you have created a new water balance document the following three tabs will be displayed e Extraction V 2 p 186 e Postprocessings V 2 p 187 e Postprocessing Detail V 2 p 188 e Results V2 p 190 Related items e Using the Water Balance Tool V 1 p 123 MIKE SHE Editors 185 Se Water Balance Editor 8 1 Extraction Water movement simulation Flow result catalogue file C 5 Testing MSHE projects Odensee Odense2003 hrs Type of extraction Area Type Catchment X Resolution Type area v m Sub catchment arid codes Type of input file Dfs2 Iteni Gross files Pre name of gross files M Use default filename Flow result catalogue file A MIKE SHE simulation generates various output files depending on the option
127. In this case storage is merely instead of Eq 1 given as S k O k Q thd 17 34 where kp is the time constant for the percolation outlet Q is percolation k is the time constant for the overflow outlet Q is outflow from the over flow outlet and thd is the threshold value for the overflow outlet Combining equation 17 34 and 17 32 and solving for S still assuming 7 is constant in time yields the following expressions for Q and Q at time t dt katk k k kko a k 7 tha 1 koko a 17 35 Qp Q k k k e k thd Q ppp ii 17 36 oO 17 2 2 General Description In the linear reservoir method the entire catchment is subdivided into a number of subcatchments and within each subcatchment the saturated zone is represented by a series of interdependent shallow interflow reser voirs plus a number of separate deep groundwater reservoirs that contrib ute to stream baseflow An example of a subdivision of a catchment area is outlined in Figure 17 8 where the topographical zones represent the inter flow reservoirs in the model If a river is present water will be routed through the linear reservoirs as interflow and baseflow and subsequently added as lateral flow to the river If no river is specified the interflow and baseflow will be simply summed up and given as total outflow from the catchment area The lateral flows to the river i e interflow and baseflow are by default routed to the river
128. K is the horizontal hydraulic conductivity in the grid cell da is the vertical surface available for exchange flow dx is the grid size used in the SZ component and ds is the average flow length The average flow length ds is the distance from the grid node to the middle of the river bank in the triangular river link cross section ds is limited to between 1 2 and 1 4 of a cell width since the maximum river link width is one cell width half cell width per side There are three variations for calculating da e Ifthe water table is higher than the river water level da is the saturated aquifer thickness above the bottom of the river bed Note however that da is not limited by the bank elevation of the river cross section which means that if the water table in the cell is above the bank of the river da accounts for overland seepage above the bank of the river e Ifthe water table is below the river level then da is the depth of water in the river e If the river cross section crosses multiple model layers then da and therefore C is limited by the available saturated thickness in each layer The exchange with each layer is calculated independently based on the da calculated for each layer This makes the total exchange inde pendent of the number of layers the river intersects This formulation for da assumes that the river aquifer exchange is prima rily via the river banks which is consistent with the limitation that there is no
129. MIKE SHE Richards Equation Se The 7 and Fz can be calculated by combining Eqs 16 11 and 16 13 as follows G D A F E aes F 7 1 A E B J A E B 16 14 Given the boundary conditions at the bottom and top nodes y is com puted for all nodes in a double sweep procedure 1 Eand F values is calculated from Eqs 16 12 and 16 14 for all nodes from bottom to top in a E F sweep 2 wis then calculated from Eq 16 13 for all nodes in a top to bottom sweep Briefly the iterative procedure within each time step is 1 the final result at time n i e C and K is used for the initial estimate of C and K for the first iteration 2 then the following convergence criteria are checked for every node after each iteration i abs wi wi lt tolerance criteria for lt 0 5 16 15 yi wi SER abs lt tolerance criteria for 0 5 16 16 yw 3 if either of these convergence criteria is satisfied then a solution at the current time level i e n has been found 4 if the criteria are not fulfilled then Ci and Ki are updated for the next iteration by Cit Hf gt cp ric 16 17 m 1 Kit 4 5 Ky six 16 18 m 1 Technical Reference for Water Movement 267 LAA Unsaturated Flow Reference 16 1 2 Boundary Conditions The unsaturated zone extends from the ground surface to the groundwater table The vertical flow is determined by the boundary condi
130. MIKE SHE USER MANUAL VOLUME 2 REFERENCE GUIDE DHI Software 2007 8 December 2006 1 28 pm Please Note Copyright This document refers to proprietary computer software which is protected by copyright All rights are reserved Copying or other reproduction of this manual or the related programs is prohibited without prior written consent of DHI Water amp Environment DHD For details please refer to your DHI Software Licence Agreement Limited Liability The liability of DHI is limited as specified in Section HI of your DHI Software Licence Agreement IN NO EVENT SHALL DHI OR ITS REPRESENTATIVES AGENTS AND SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSO EVER INCLUDING WITHOUT LIMITATION SPECIAL INDIRECT INCIDENTAL OR CONSEQUENTIAL DAMAGES OR DAMAGES FOR LOSS OF BUSINESS PROFITS OR SAVINGS BUSINESS INTERRUPTION LOSS OF BUSINESS INFORMATION OR OTHER PECUNIARY LOSS ARISING OUT OF THE USE OF OR THE INA BILITY TO USE THIS DHI SOFTWARE PRODUCT EVEN IF DHI HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES THIS LIMITATION SHALL APPLY TO CLAIMS OF PERSONAL INJURY TO THE EXTENT PERMITTED BY LAW SOME COUN TRIES OR STATES DO NOT ALLOW THE EXCLUSION OR LIMITA TION OF LIABILITY FOR CONSEQUENTIAL SPECIAL INDIRECT INCIDENTAL DAMAGES AND ACCORDINGLY SOME PORTIONS OF THESE LIMITATIONS MAY NOT APPLY TO YOU BY YOUR OPENING OF THIS SEALED PACKAGE OR INSTALLING OR USING THE SOFTWARE YOU HAVE ACCEPTED THAT THE AB
131. Model Components For the saturated zone in MIKE SHE there are two solvers to choose from e the pre conditioned conjugate gradient method and e the successive over relaxation method The Successive Over relaxation solver is the original solver in MIKE SHE and the Pre conditioned Conjugate Gradient Solver is based on the USGS s PCG2 solver for MODFLOW Hill 1990 Steady state vs Transient Simulations The Solver type controls whether or not the simulation is run as a Steady state model or not if you chose the Pre conditioned Conjugate Gradient Steady State option then the simulation will be run in steady state Other wise the simulation will be run as a transient simulation 40 MIKE SHE Simulation Specification LEA If the SZ simulation is steady state then the PCG solver is the only solver available Although the same options are available for both the steady state and the transient PCG solvers the optimal parameters or combination of parameters and options is most likely different in the two cases Thus the recommended settings are different in both cases Iteration Control Iteration Control Maximum no of iterations o oo Maximum head change per iteration 0 005 m Maximum residual error m d oos Variable Units Maximum number of iterations Maximum head changed per iteration EUM elevation Maximum residual error m day The iteration procedure can be stopped when either the
132. OVE LIMITATIONS OR THE MAXIMUM LEGALLY APPLICA BLE SUBSET OF THESE LIMITATIONS APPLY TO YOUR PUR CHASE OF THIS SOFTWARE Printing History December 2007 Edition 2007 MIKE SHE CONTENTS Se The MIKE SHE Reference Guide 15 1 REFERENCE GUIDE OVERVIEW 2 0 2200008 17 2 SETUP DATA TAB aca manpas amaaa Bade eo Agee eee aK eee ES 19 241 Display 4 2 vee erg amp 4 eee bet Dace ee ete eee eH eS 20 2 1 1 Foreground Backoround 42 2 cue ee ee hs ee 21 2 1 2 Image Overlays 2264468 eee ee eb eedeteecude 22 2 1 3 Grid Overlays a4 had 2 alee A ae ee Be Ree ey eS 23 214 Shape Overlays 244244 Peed Bewed Pu eh wha Bax 24 2 1 5 River Overlays lt b lt 4 cen eo doe adhe uae ae oe ee d 25 2 1 6 MIKE SHE Well Database Overlays 25 2 1 7 GurrentLayer 3 656 2adoy ode eee de Me eee oes 26 2 2 Simulation Specification naaa aaa 26 2 2 1 Simulation Title xugadgek aged eed eee h kaw de od 28 2 2 2 Simulation Period 2 4 2 gine eds aes MADR eee be 28 220 Time step Control 4400s gee eee be EE we ee 30 2 2 4 OL Computational Control Parameters 34 2 2 5 UZ Computational Control Parameters naaa aaa aaa 39 2 2 6 SZ Computational Control Parameters 40 2 3 Water Quality Simulation Specification 45 251 Wo Simulation Title 2 aise 6 eer dw et Gee Se ed 46 2 3 2 WQ Simulation Period
133. Oe we 300 17 1 5 The Sheet Pile Module 300 Se 17 1 6 The Successive Overrelaxation SOR Solver 301 17 2 Linear Reservoir Method 222004 307 17 2 1 Linear Reservoir Theory 2 00005 308 17 2 2 General Description 200 4 309 17 2 3 Subcatchments and Linear Reservoirs 312 17 2 4 Calculation of Interflow 04 313 17 2 5 Calculation of Interflow Percolation and Dead Zone Storage 315 17 2 6 Calculation of Basefow 316 17 21 UZ COUP IN 246 22S a e oo ee Re Pe de ee SS 317 17 2 8 Coupling to Mike 11 2 6 2646454545 e be ee eee eee ee 318 17 2 9 Limitations of the Linear ReservoirMethod 318 Technical Reference for Water Quality 321 18 WATER QUALITY OVERVIEW 2 20 0 0 0 00 2 ee ee 323 19 ADVECTION DISPERSION REFERENCE 325 19 1 Simulation CONG 4 4 224 2 cava hd bh ob hd aA Yee BS 325 19 1 1 Flow Storing Requirements 325 19 1 2 Internal Boundary Conditions 325 19 1 3 Time step calculations 327 19 2 Solute Transport inthe Saturated Zone 329 19 2 1 Governing Equations 44 42 6440 26 4644608 ae eee nd 330 19 2 2 Solution Scheme 000 eee eee eee 334 19 2 3 Initial Conditions e264 Guu od bE OS Cw ke w Sw S 338 19
134. R uy u u u u u 7 u B Blu 2 2 u uy Uy u u Llu B Blu 21 4 lul Ju tuy tu 21 5 B lul 2u u u 21 6 J2 azlul D 0 0 B 0 J2 a ru Dy 0 21 7 L 0 O Jaru Dn ay and o are the longitudinal and transversal dispersion coefficients respectively and D is the neutral dispersion Using 21 2 repeatedly the location of a particle at time ty NAt can be determined N X N Xpt E Xp w tn V D Xp w tnt B Xp ws tn Zpne Nt 21 8 n 0 370 MIKE SHE User s Guide Governing equations Se After applying 21 8 for a large number of particles i e N the average solute concentration for an arbitrary volume can be calculated using 21 9 N p Cy y D m l o 21 9 p 1 where m is the particle mass Using this procedure an accurate solution of the advection dispersion equation 21 1 can be obtained Thompson et al 1987 Thompson and Dougherty 1988 Kitanidis 1994 The term V D X p m tn in 21 2 and 21 8 is assumed to be much smaller than the remaining term and is omitted for the benefit of the com putational speed This may however in some situations result in an accu mulation of particles near boundaries or stagnation points Kinzelbach and Uffink 1989 Uffink 1988 Kitanidis 1994 Prior to the particle tracking calculations the transient three dimensional ground water flow field must be calculated The groundwater velocities are
135. Technical Reference For the Water Movement module this includes e the Overland Flow Reference V 2 p 211 e the Channel Flow Reference V 2 p 227 e the Evapotranspiration Reference V 2 p 243 e the Unsaturated Flow Reference V 2 p 261 and e the Saturated Flow Reference V 2 p 289 For the Water Quality module this includes e the Advection Dispersion Reference V2 p 325 e the Reactive Transport Reference V 2 p 351 and The MIKE SHE Reference Guide 17 a oe Reference Guide Overview e the Particle Tracking Reference V 2 p 369 18 MIKE SHE Se 2 SETUP DATA TAB This chapter is organized around the Setup Data Tree For each branch in the data tree there is a corresponding subsection The main sections include e Display V 2 p 20 display of map overlays e Simulation Specification V 2 p 26 control and selection of water movement engines e Water Quality Simulation Specification V 2 p 45 control and selection of water quality engines e Species V 2 p 50 specification of species for water quality simula tions e Model Domain and Grid V 2 p 52 definition of model extent and grid e Subcatchments V 2 p 54 definition of catchment boundaries for lumped parameter water movement engines e Topography V 2 p 56 specification of land surface elevation e Precipitation V 2 p 57 specification and extent of precipitation measurements e
136. Transparency of surfaces The transparency factor allows you to see through the model surfaces This gives you a better feeling of what is happening below or above the surface that you are looking at Show computational layers In this case the model s computational lay ers will be visible and selectable in the GeoScene3D interface Show geological layers In this case the specified conceptual geologic layers will be visible and selected in the GeoScene3D interface Show lenses If you select to show lenses then they will be displayed on top of the geologic layers 153 LAA Preprocessed Data Tab 154 MIKE SHE GeoScene3D LAA 4 RESULTS TAB MIKE SHE Flow Model Description Results of simulation s Mike SHE Detailed Time Series s Gridded Data Results Viewer s Mike 11 Detailed Time Series Run Statistics GeoScene3D m Setup Data Processed Data Results All the simulation results are collected in the Results tab This includes Detailed time series output for both MIKE SHE and MIKE 11 as well as Grid series output for MIKE SHE A Run Statistics tool is available for helping you assimilate the calibration statistics for each of the detailed time series plots A link to the GeoScene3D program is also included where you can visual ize your results in a dynamic 3D environment 155 a oe Results Tab 4 1 MIKE SHE Detailed Time Series Refresh Obs C
137. Unsaturated Zone V 2 p 90 e Column Classification V2 p 91 e Partial automatic classification V 2 p 97 e Specified classification V 2 p 98 3 1 6 Saturated Zone Items The saturated zone items are organized by item with separate maps per layer Layer thickness Layer thickness is a derived value calculated by subtracting the top and bottom elevations of the layer The EUM type is thickness with a MIKE Zero default unit of millime ters This is not very suitable for geologic layers that can be more than 100m thick To change the default units see EUM Data Units V 1 p 271 find the thickness item and change the default unit to meter or feet as appropriate Transmissivity Transmissivity is also a derived value calculate by multiplying the thick ness by the horizontal hydraulic conductivity 3 1 7 Saturated Zone Drainage The rate of saturated zone drainage is controlled by the drain elevation and the drain time constant However the destination of the drainage water is controlled by drain codes which determine if the water flows to a bound ary a local depression or a river SZ Drainage Codes The SZ Drainage Codes map is the drainage codes specified in the Drain Codes V 2 p 127 set up item interpolated to the model grid 151 LAA Preprocessed Data Tab During the preprocessing each active drain cell is mapped to a destination cell The destination cell is determined from the drain cod
138. V 2 p 316 2 16 3 Geological Units ie DI 1 4e 006 2e 006 3e z DS TS 10 5e 005 1e 005 ae 3e 005 6 ES 3 5e 005 1e 005 0 15 3e 005 i FT 4 4e 007 2e 007 0 15 3e 005 06 FPFSML 8 4e 008 2e 008 0 1 3e 005 06 e HG 6 2e 005 6e 006 015 3e 005 06 7 HS 7 16 005 2e 006 0 15 3e 005 06 8 MS 9 2e 005 4e 006 0 415 3e 005 06 If you specify your geologic conceptual model via geological units you can add each of your geologic units and its associated hydrogeologic prop erties to the table Then instead of specifying the hydrogeologic proper ties for each geological layer you only need to specify the distribution of the units within the geologic layer or lense Related Items e Horizontal Hydraulic Conductivity V 2 p 112 e Vertical Hydraulic Conductivity V2 p 113 108 MIKE SHE Saturated Zone es e Specific Yield V2 p 114 e Specific Storage V 2 p 114 Porosity V 2 p 115 e Dispersion Coefficients LHH THH TVH LVV THV V 2 p 1 5 2 16 4 Geological Layers r Geological layers For each geologic layer you must specify the hydrogeologic parameters of the layer including e Lower Level Geological Layer or Lense or Water Quality Layer e Horizontal Hydraulic Conductivity e Vertical Hydraulic Conductivity e Specific Yield e Specific Storage If you define your hydrogeology by then most of the physical properties will be defined as properties of the Geological Unit and there will be a
139. a tion directory Technical Reference for Water Quality 349 Advection Dispersion Reference 350 MIKE SHE User s Guide Sorption LEA 20 REACTIVE TRANSPORT REFERENCE Several reaction processes can be added to the solute transport calcula tions including e Sorption and desorption e Degradation and e Plant uptake In the saturated and unsaturated all three of these processes are available However in the overland flow only degradation is available but in MIKE 11 advanced reactions are possible using ECOLAB which is a general equation solver for any kinetic reaction process The conservative transport of solutes in the unsaturated zone and in the groundwater is governed by the normal advection dispersion equation described in Equation 19 3 When processes such as sorption and decay are included the equation is extended to 20 1 where p is the bulk density of the porous medium is the porosity of the porous medium c is the mass of solutes sorbed per dry unit weight of solid and the term dc 6t on the right hand side is a term indicating a bio logical or chemical reaction of the solute This way of describing reaction processes is very simplified and in some cases may give incorrect results Nevertheless it is a very common way of describing the reaction processes in hydrologic systems 20 1 Sorption Sorption includes a number of geochemical and chemical reactions such as adsorption
140. age The option has been found to have a dampening effect when the groundwater table fluctuates around the drainage level between itera tions and does not entail reductions in the drain flow in the final solu tion Mean values of horizontal SZ conductance To prevent potential oscillations of the numerical scheme when rapid changes between dry and wet conditions occur a mean conductance is applied by taking the conductance of the previous outer iteration into account Under relaxation The PCG solver can optionally use an under relaxation factor between 0 0 and 1 0 to improve convergence In general a low value will lead to con vergence but at a slower convergence rate i e with many SZ iterations Higher values will increase the convergence rate but at the risk of non convergence Automatic dynamic estimation of under relaxation factors If the automatic estimation of the under relaxation factor is allowed the under relaxation factor is calculated automatically as part of the outer iter Technical Reference for Water Movement 293 LEA Saturated Flow Reference ation loop in the PCG solver The algorithm determines the factors based on the minimum residual 2 norm value found for 4 different factors To avoid numerical oscillations the factor is set to 90 of the factor used in the previous iteration and 10 of the current optimal factor The time used for automatic estimation of relaxation factors may be sig
141. age Coefficient 85 Output p vtenen See a See au 143 Linear Reservoir Ground watertable 97 Limitations 318 Groundwater Table 101 One Outlet 308 Subcatchments 312 H Two Outlets 309 Horizontal Extent 111 Linear Reservoir Method 102 307 Hydraulic Conductivity Description 309 Horizontal 112 Lower Level 111 Vertical 113 M l Manning number 83 Import oaaae 139 170 Map Coordinates 201 tOfile 171 Maximum Residual Error TAB delimited text file 172 POG Ward eae heed e aS ee 293 Infiltration 279 SOR Ph be ol 8 Be ee 305 383 Se Index MIKE 11 Results Viewer Detailed Time Series 159 Gridded Data 157 Output 22254 dee Goat oes 141 Richards Equation 262 MIKE 11 Water Levels 232 River Links 55 Model Domain 52 River Overlays 25 Model Grid g4 4444 46094644 52 River Aquifer Exchange 234 Full Contact 234 N Reduced Contact 235 237 Net Rainfall Fraction 59 Root Distribution 247 Numerical formulation Root Mass Distribution Parameter 67 SOR 301 Numerical Solution 216 263 S Saturated Flow 289 O Saturated Zone 102 Option Distribution
142. age terms The storage capacity is computed by S2 h S1 h Ay SAU ap tE M 17 11 where n is time step S is the storage capacity at the start of the iteration at time step n and S2 is the storage capacity at the last iteration For confined cells the storage capacity is given as S Ax2AzS 17 12 292 MIKE SHE 3D Finite Difference Method a oe and for unconfined cells the storage capacity is given as S AXShree 17 13 Maximum Residual Error The maximum residual error is the largest allowable value of residual error during an iteration The solution is obtained when the residual error during an iteration in any computational node is less than the specified tol erance The value of the maximum residual error should be selected according to aquifer properties and the dimensions of the model In practice the maxi mum residual error value will always be a compromise between accuracy and computing time It is recommended to check the water balance care fully at the end of the simulation but it should be emphasized that large internal water balance errors between adjacent computational nodes may not be detected If large errors in the water balance are produced the maxi mum residual error should be reduced Gradual activation of SZ drainage To prevent numerical oscillations the drainage constant may be adjusted between 0 and the actual drainage time constant defined in the input for SZ drain
143. al Data EUM Data Units Depth below ground In unsaturated fine soils capillary action can lead to saturated conditions existing some distance above the water table If the water table is close to the ground surface ET will continue to occur at the maximum rate so long as this capillary zone reaches the ground surface That is evapotrans piration will not decrease the saturation but draw water directly from the water table due to capillary action Similarly when the water table is deeper plant roots will draw water directly from the saturated zone as long as the roots reach the capillary zone The ET surface depth equals the thickness of the capillary zone It is used as the water table depth at which the ET starts to decrease That is if the 100 MIKE SHE Groundwater Table Ss water table falls below the ET surface then the linear function that reduces ET becomes active In coarse to medium sands the ET surface depth is typically less than 10cm In fine sands and silts the ET surface depth could be a half a metre or more Note The ET surface depth must be greater than zero Related Items e Unsaturated Flow Reference V 2 p 261 e Two Layer Water Balance V 2 p 275 e Simplified ET for the Two Layer Water Balance Method V 2 p 254 2 15 Groundwater Table Groundwater Table Conditions If Unsaturated Flow selected in the Simulation Specifi cation dialogue without selecting Saturated Flow OR
144. alances if the time steps are different Ci Co and C3 The equations for actual transpiration Eq 15 3 and soil evaporation Eq 15 8 contain three empirical coefficients C1 C2 and C3 The coeffi cients C and C are used in the transpiration function f LAD Eq 15 4 C3 is also part of Eq 15 3 but is the only variable found in the soil moisture function Eq 15 5 C C is plant dependent For agricultural crops and grass C has been estimated to be about 0 3 C influences the ratio soil evaporation to transpiration This is illustrated in Figure 15 7 For smaller C values the soil evaporation becomes larger relative to transpiration For higher C values the ratio approaches the basic ratio determined by C and the input value of LAI C2 For agricultural crops and grass grown on clayey loamy soils C has been estimated to be about 0 2 Similar to C4 C3 influences the distri bution between soil evaporation and transpiration as shown in Figure 15 8 For higher values of C a larger percentage of the actual ET will be soil evaporation Since soil evaporation only occurs from the upper most node closest to the ground surface in the UZ soil pro file water extraction from the top node is weighted higher This is illustrated in Figure 15 8 where 23 per cent and 61 per cent of the total extraction takes place in the top node for C values of 0 and 0 5 respec tively Thus changing C will influence the ratio
145. ally Then simple loading the shp file in a different dia logue The Editor consists of three parts the map coordinate text boxes the interactive map view and the toolbar in the top menu Map Coordinates The map coordinates are used to change the displayed extents of the map view Thus if you want to create a polygon larger or much smaller than MIKE SHE Editors 201 LRA Simple Shape Editor the current map view in the Setup Tab you can change the coordinates of the lower left hand corner or the upper right hand corner of the map view Interactive Map The interactive map is used to display the polygon or polygons that your are editing You can use the icons in the toolbar to add move delete rename etc the polygons in the map view The following is a description of the icons Create Polygon To create a polygon click on this icon then left click once on the map and trace the polygon on the map that you want to create while holding down the left mouse button This will create a series of points along the line that you trace If you want to stop simply lift the left mouse button and reposition the mouse when you want to start again To finish and close the polygon double click the left mouse button i Select Move Polygon To select a polygon click on this icon and then click on the polygon that you want to select This will make all of the nodes on the polygon visible by adding node markers around the
146. ameters for Precipitation dependent time step control Periods of heavy rainfall can lead to numerical instabilities if the time step is too long To reduce the numerical instabilities the a time step control has been introduced on the precipitation and infiltration components You will notice the effect of these factor during the simulation by suddenly seeing very small time steps during storm events If your model does not include the unsaturated zone or if you are using the 2 Layer water balance method then you can set these conditions up by a factor of 10 or more However if you are using the Richards equation method then you may have to reduce these factors to achieve a stable solution Max precipitation depth per time step If the total amount of precipita tion mm in the current time step exceeds this amount the time step will be reduced by the increment rate Then the precipitation time series will be re sampled to see if the max precipitation depth criteria has been met If it has not been met the process will be repeated with progressively smaller time steps until the precipitation criteria is satis fied Multiple sampling is important in the case where the precipitation time series is more detailed than the time step length However the cri teria can lead to very short time steps during short term high intensity events For example if your model is running with maximum time steps of say 6 hours but your precipitation time series
147. ancel The Vegetation dialogue also includes a button labelled ET Parameters Clicking on this button pops up the dialogue for specifying the default ET parameters for the Kristensen and Jensen model The Evapotranspiration parameters in this dialogue do not vary in time and are global for the model However if the Vegetation Properties file option is used for the Leaf Area Index and Root Depth parameters these values can be overrid den by crop specific values specified in the vegetation properties file The following sections are condensed from the description of the Kris tensen and Jensen method in the Evapotranspiration Reference chapter which should be consulted for more detailed information Interception Coefficient C The interception process is modelled as an interception storage which must be filled before stem flow to the 65 Setup Data Tab ground surface takes place The coefficient C defines the interception storage capacity of the vegetation per unit of LAI A typical value is about 0 05 mm but a more exact value may be determined through cal ibration see Equation 15 2 Note The interception storage is calculated each time step and the rate of evaporation is usually high enough to remove all the interception storage in each time step Thus the total amount of water removed from interception storage depends on the length of the time step This can lead to confusion when comparing water b
148. ant the WQ time step to be uniform during the WQ simulation Stability Criteria The courant number is a measure of the ratio of flow rate to grid size For numerical stability it is important that the solutes do not travel too far in one time step The time step is reduced until all the time step criteria below are met Max Advective Courant Number The advective courant number rep resents the ratio of how fast a particle moves in the flow field to the cell size This criteria is likely to be controlling if your flow velocities are high or your dispersivity values are very low or zero The default value is 0 8 If your actual time step is being controlled by this criteria then you could increase it to make the simulation run faster However 49 LEA Setup Data Tab you will need to check to make sure the simulation has converge prop erly and that the mass balance is reasonable Max Dispersive Courant Number The dispersive courant number rep resents the ratio of how fast a particle moves across a cell due to dis persion to the cell size This criteria is likely to be controlling when the velocities are very slow and the dispersivity is non zero The default value is 0 5 If your actual time step is being controlled by this criteria then you could increase it to make the simulation run faster However you will need to check to make sure the simulation has converge prop erly and that the mass balance is reasonable Max
149. anually and use the command line interface to run 45 Setup Data Tab 2 3 1 the executable For a detailed description on how to do this refer to Using the Fully Integrated AD Module V p 197 Also available from the command line is the random walk particle tracking method which is described in Working with Particle Tracking V p 229 WQ Simulation Title Simulation Title ee o Simulation Description pe o WQ Simulation Title Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue Title and Description The Title and Description will be written to out put files and appear on plots of the simulation results 46 MIKE SHE Water Quality Simulation Specification ao 2 3 2 WQ Simulation Period MWO Simulation Period Start Date 2000 01 01 00 00 End Date 2000 02 01 00 00 H M Flow Results for Water Quality Simulation C No recycling on flow results Recycling on flow results Cycle Restart Date 2000 01 01 00 00 H Cycle End Date 2000 02 01 00 00 x Constant Water Movement Flow Field Date for Flow Field Solution 2000 02 01 00 00 H X WQ Simulation Period Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue WQ Simulation Period The water quality simulation does not have to be
150. arying dfs2 file which is typically extracted from a regional results file This can be done using the MIKE Zero Toolbox Extraction tool 2D Grid from 3D files MIKE SHE then inter polates in both time and space from the dfs2 file to the local head boundary at each local time step Zero flux This is a no flow boundary which is the default Flux This boundary describes a constant or time varying flux across the outer boundary of the model A time varying flux can be specified as a mean step accumulated discharge e g m3 s or as a step accumulated volume e g m3 A positive value implies an inflow to the model cells Gradient This boundary describes a constant or time varying gradient between the node on the outer boundary and the first internal node A time varying gradient can be specified as an instantaneous dimension less or percent value A positive gradient implies a flux into the model Notes 1 The head is calculated in a No Flow outer boundary cells whereas the head is specified in the Fixed Head outer boundary cells but in both cases all properties must be assigned to all outer boundary cells 2 An internal model cell in contact with multiple boundary cells will not receive multiple quantities of water 119 Setup Data Tab Additional detailed information can be found under Boundary Condi tions V 2 p 296 in the Technical Reference for the Saturated Zone module An error will be generated if the flux
151. as their only source of inflow Each baseflow reservoir can discharge to pumping wells to the unsaturated zone adjacent to streams and rivers i e the zone beneath the lowest interflow reservoir as well as directly to the MIKE 11 river network 106 MIKE SHE Saturated Zone Se In the primary baseflow reservoir map view you can define the number of baseflow reservoirs in your system You can define any number of base flow reservoirs but typically there are only one or two For each baseflow reservoir pair there are three items to define Fraction of percolation to reservoir 1 this is used to divide the percola tion between each of the two parallel baseflow reservoirs Fraction of pumping from reservoir 1 this is used to divide the pump ing if it exists between each of the two parallel baseflow reservoirs Use default river links in most cases you will link the simplified over land flow and the groundwater interflow to all of the river links found in the lowest interflow reservoir in each subcatchment However in some cases you may want to link the flow to particular river links For example if your MIKE 11 river network does not extend into the sub catchment you can specify that the interflow discharges to a particular node or set of nodes in a nearby river network If you uncheck this checkbox a River Links sub item will appear where you can specify the river branch and chainage to link the sub catchment
152. ase flow reservoirs in each of the Deep Groundwater Routing Zones This is a limitation in the sense that occasionally you may find that fast response and the slow response baseflow may contribute to different parts of the stream e When calculating the unsaturated flow the bottom boundary condition is input from a separate file not calculated during the simulation This means that changes in the water levels in the reservoirs will have no effect on the UZ boundary condition e Currently the subcatchment based linear reservoir module cannot be combined with irrigation This would require changing the way groundwater pumping was handled in the irrigation module if the water was being extracted from a groundwater linear reservoir 318 MIKE SHE Linear Reservoir Method a oe e The numerical solution used for the Linear Reservoir module assumes that the inflow to each of the linear reservoirs is constant within a time step Strictly speaking this is not correct as outflow from each reser voir changes exponentially during a time step The calculation proce dure uses the mean outflow from the upper reservoir as inflow to the downstream reservoir In this way there is no water balance error but the dynamics are somewhat dampened If this is a problem smaller time steps can be chosen which will lead to a more accurate solution as the changes in flow become smaller during each time step e The linear reservoir module cannot be co
153. ate in practice Thus if we assume that the porous medium is symmetric around one of the axis the number of non zero dispersivities can be limited to five This assumption is true if the medium is made up of layers normal to the axis of symmetry which is the case for some geological deposits Under these Technical Reference for Water Quality 331 Ss Advection Dispersion Reference conditions the following expression for the a nn terms Bear and Verruijt 1987 have been derived Gime ar Og Drm an Fim Fyn Oy Sim am djhminn Syn ti hy F ar Sim hy hn Oyj Hi Bon Cin hj dam pr Sja hi am ay a hy huha ay fa hj fau 19 8 where az an Gy ary and ay are independent parameters and h is a unit vector directed along the axis of symmetry In MIKE SHE AD it is assumed that the axis of symmetry always coincides with the z axis and h becomes equal to 0 0 1 Five dispersivities are then introduced Qz the longitudinal dispersivity in the horizontal direction for horizontal flow Qrp the transversal dispersivity in the horizontal direction for horizontal flow Qzyy the longitudinal dispersivity in the vertical direction for verti cal flow Qryp the transversal dispersivity in the vertical direction for hori zontal flow Qryy the transversal dispersivity in the horizontal direction for vertical flow MIKE SHE User s Guide Solute Transport in the Saturated Zone ao Thus
154. ater content above the datum Zo Zo should always be lower than the lowest elevation of the water table is designated W the the UZ contribution to the E error term in UZ time step n to n is qil W 1 W At 4 46 16 29 where W the new water content q the infiltration rate negative downwards qg the evapotranspiration loss Note negative values of qu indicate downward flow 2 Assuming that the groundwater outflow in a cell is steady the accumu lated error at UZ time n is At cum ngt 1 NG qg Eiin as fgg ve 16 30 284 MIKE SHE Coupling the Unsaturated Zone to the Saturated Zone a e Mn EQUILIBRIUM e PROFILE 0 V2 Va ne ANIM tinal V2 STEFWISE HAN x 9E wa hom DATUM Zo a b Figure 16 7 a Soil moisture content at two times n and n m without corrections and b Soil moisture content at time n m before and after correction where ae positive outwards is the sum of the groundwater out flow rate for the cell in the last groundwater time step ng scaled to the new SZ time step length ng and q i positive outwards is the sum of source sink terms calculated by the UZ module for the current time n e g stream aquifer exchanges irrigation It should be noted that if Eeum is less than zero there is a deficit of water stored in the column and if Ecum is greater than zero there is an excess of water stored in the co
155. ater will spill across the bank based on the standard weir formula Hy Ha i 14 8 Hs a A O E ME A 1 where Q is the flow across the weir Ax is the cell width C is the weir coefficient H and Hqs refer to the height of water on the upstream side and downstream side of the weir respectively H is the height of the weir and k is a head exponent If the water levels are such that water is flowing to the river then the over land flow to the river is added to MIKE 11 as lateral inflow If the water 240 MIKE SHE Direct Overbank Spilling to and from MIKE 11 LEA level in the river is higher than the level of ponded water then the river water will spill onto the MIKE SHE cell and become part of the overland flow If the upstream water depth over the weir approaches zero the flow over the weir becomes undefined Therefore the calculated flow is reduced to zero linearly when the upstream height goes below a threshold If you use the overbank spilling option then you should also use the Explict Numerical Solution V 2 p 217 for overland flow Technical Reference for Water Movement 241 Channel Flow Reference 242 MIKE SHE Direct Overbank Spilling to and from MIKE 11 on 15 EVAPOTRANSPIRATION REFERENCE The calculation of evapotranspiration uses meteorological and vegetative data to predict the total evapotranspiration and net rainfall due to e Interception of rainfall by
156. ation the flood mapping procedure calculates the surface water level on top of each MIKE SHE cell with a flood code by comparing the MIKE 11 surface water level to the surface topography in the model grid A grid cell is flooded when the MIKE 11 surface water level is above the topography The MIKE 11 water level is then used as the level of pon ded surface water The actual water level in the grid cell is calculated as a distance weighted average of the upstream and downstream MIKE 11 H points 14 3 2 Calculation of the Exchange Flows After the MIKE SHE overland water levels have been updated MIKE SHE calculates the infiltration to the unsaturated and saturated zones and evapotranspiration Thus MIKE SHE simply considers any water on the surface including MIKE 11 flood water as ponded water disregarding the water source In other words ponded rainfall and ponded flood water are indistinguishable MIKE SHE does not calculate overland flow between cells that are flooded by MIKE 11 Nor does MIKE SHE calculate overland exchange to MIKE 11 if the cell is flooded by MIKE 11 However lateral overland flow to neighbouring non flooded cells is allowed Thus if there is a neighbouring non flooded cell with a topography lower than a flooded Technical Reference for Water Movement 239 Channel Flow Reference cell s water level then MIKE SHE will calculate overland flow to the non flooded cell as normal The calculated
157. ation i 162 MIKE SHE GeoScene3D 4 5 GeoScene3D M GeoScene settings Vertical exaggeration Factor 10 Transparency of surfaces 0 2 Show computational layers Show geological layers F Show Lenses IV Use all time steps Show every l time step Lanuch GeoScene3D The GeoScene3D dialogue provides a link to the GeoScene3D program for viewing the model results Vertical exaggeration factor In most models the lateral extent is sev eral orders of magnitude greater than the vertical extent Thus without a vertical exaggeration factor the model view will be too thin to be useful A vertical exaggeration of 10 to 30 will typically give you a good looking model that accentuates the vertical differences Transparency of surfaces The transparency factor allows you to see through the model surfaces This gives you a better feeling of what is happening below or above the surface that you are looking at Show computational layers In this case the model s computational lay ers will be visible and selectable in the GeoScene3D interface Show geological layers In this case the specified conceptual geologic layers will be visible and selected in the GeoScene3D interface Show lenses If you select to show lenses then they will be displayed on top of the geologic layers Use all time steps The default action is to display time varying data with all of the time steps 163 LEA R
158. ational 300 MIKE SHE 3D Finite Difference Method a oe layer If the Sheet Piling module is active then the horizontal conduct ance Cp for flow between two cells is calculated as 1 lt 7 17 18 mE nE E N 2 k dz Kieap dX dz 2 k dz where k is the hydraulic conductivity of the cells on either side of the sheet pile L T kreas the leakage coefficient of the sheet pile between the cells 1 L dz saturated layer thickness L and dz maximium of dz1 and dz2 L Similarly reducing the vertical conductance between two layers can simu late a restriction in vertical flow e g thin clay layer or liner Thus if the Sheet Piling module is active for vertical flow the vertical conductance between two layers is calculated as dx dx axax 17 19 dz 1 dz i 2 ky Rieak 2 k v where k is the hydraulic conductivity of the cells above and below the sheet pile L T keak is the leakage coefficient 1 T and dz is the layer thickness L 17 1 6 The Successive Overrelaxation SOR Solver Numerical formulation Equation 17 1 is solved by approximating it to a set of finite difference equations by applying Darcy s law in combination with the mass balance equation for each computational node Considering a node i inside the model area the total inflow Q from neighbouring nodes and source sinks between time n and time n 1 is given by DORt Dart dqrt RHAx 17 20 where q is t
159. atrix under wet conditions a 9 and Bs are used to reduce the total bypass fraction under dry conditions O19 and Bso are calculated internally by MIKE SHE and depend on the actual water contents of the unsaturated zone 10cm and 50cm below the ground surface respectively The relationship used to calculate a9 and Bso is illustrated in Figure 16 6 o and Bso vary linearly between 0 0 and 1 0 when the water content is between 0 and 04 If the water content is below 05 O19 and Bso equal 0 0 If the water content is above 0 amp 9 and Bso equal 1 0 Typically macropore flow is highest in wet conditions when water is flowing freely in the soil e g moisture content above the field capacity Orc and zero when the soil is very dry e g moisture content at the wilting point Owp 280 MIKE SHE Lumped UZ Calculations Sx Oz 8 SOIL MOISTURE O soem 50m Figure 16 6 a and as a function of the soil moisture content 10 cm and 50 cm below the ground surface respectively 16 5 Lumped UZ Calculations In principle unsaturated flow should be calculated individually for every ground surface node in the model domain However for large models the unsaturated flow calculations can become by far the most time consum ing part of the solution In particular solving Richards equation in every grid square can be quite time consuming when simulating long time series of rainfall To reduce the computational burden it is p
160. ave been suggested to derive the function from more easily measurable characterizing proper ties of the soil or simply to rely on empirical relationships Reviews of various methods for predicting the conductivity function can be found in the literature The data points describing the pressure conductivity curve can be given as a table of pF versus K values The table should be specified starting with the lowest value of pF wettest condition and given in increasing order of pF To get a smooth hydraulic conductivity curve MIKE SHE adopts a cubic spline curve fitting procedure As a minimum you should specify the con ductivity at saturation the field capacity and the wilting point However this we strongly advise against this because the cubic spline function is unlikely to be able to fit an appropriate function to only 3 points In the Averjanov method the hydraulic conductivity K is described as a function of the effective saturation Se Kg Koat 6 1 where S 0 0 0 0 6 2 in which 6 O and 0 are saturated actual and residual moisture contents respectively The full knowledge about the hydraulic conductivity function is seldom available and the parameter n has to be estimated by calibration As a guideline the exponent n is usually small for sandy soils 2 5 and large for clayey soils 10 20 It is important to note that the value of the MIKE SHE Editors 175 oa UZ Soil Properties Editor
161. be calculated by pa peg a GE De dx dx dx pa le 3 5 8 5 5 RO L Pea 8 m a m m a The depth y near the leading edge of the flow plane can be related to the depth at equilibrium by y 4 y 13 24 where f is the time and is the time until the equilibrium is reached Then from 13 21 we can write 13 j m t7 3 da m s 13 25 e Now if we integrated the specific discharge from time 0 to when the equi librium is reached we can calculate the total volume discharged Q per unit width of the plane by Technical Reference for Water Movement 221 Overland Flow Reference e 5 3 adi fu 4 y3 Jacan oO oIa o a M y Ja t m2 13 26 From 13 25 at equilibrium t t the depth of water at the leading edge of the plane x L is q M y Ja R L 13 27 which yields Ts r a 13 28 aa From continuity the total volume of inflow up until equilibrium must equal the total outflow minus the amount retained on the surface Thus Inflow Outflow Surface storage which from equations 13 26 and 13 23 yields 3 5 3 5 ROLA R Li My fat 2255 13 29 which when simplified yields the time to reach equilibrium 3 5 eee a S eas 4 3 53 10 R M Ca 5 13 30 If we now assume that the flow on the sloping plane is uniform that is the change in discharge as a function of x is zero then the depth prior to equi librium is simply y R t 13 31
162. boundary between two blocks with different cell heights the two adjacent boundary cells are adjusted to give a smoother change in cell heights Bypass Constants The bypass parameters include byp the maximum bypass fraction between 0 and 1 0 of the net rainfall thr1 6 the threshold water content below which the bypass frac tion is reduced and thr2 02 the minimum water content at which bypass occurs Related Items e Unsaturated Flow Reference V 2 p 261 e Richards Equation V 2 p 262 e Gravity Flow V 2 p 273 e Simplified Macropore Flow bypass flow V 2 p 280 95 LEA Setup Data Tab 2 14 2 Groundwater Depths used for UZ Classification 1 1 2 2 5 i Water Table for Classification C Use initial water table for classification Specified water table for classification Groundwater Depths used for UZ Classification Conditions if either the Automatic or Partially automatic column classifications selected in the main Unsaturated Zone dialogue The automatic or partially automatic classification requires a distribution of groundwater elevations see the main Unsaturated Zone dialogue This can be either the initial depth to the groundwater based on the initial heads default option or you can supply a dfs2 map of the groundwater eleva tions second option If you chose the second option then a new item Ground Water Table will appear in the data tree In both ca
163. bove the drain at the beginning of the time step d is the depth of water above the drain at the end of the time step and S is the specific yield Qj is calculated based on the mean depth of water in the drain during the time step Thus dy d 2 On Cy SA 17 27 where C4 is the drain conductance or time constant Substituting 17 26 and 17 27 into 17 25 and rearranging the water depth at the end of a time step d can be calculated by CA a s k EqAt oe 17 28 s 306 MIKE SHE Linear Reservoir Method a oe From which the new water table elevation h at the end of the time step can be calculated by h Zy d 17 29 where Zg is the elevation of the drain The drainage outflow is added as a sink term using the hydraulic head explicitly The computation for drainage flow uses the UZ time step which is usually smaller than the SZ time step The initial drainage depth do at the beginning of an SZ time step is set equal to h Zdr where h is the water table elevation at the end of the previous SZ time step d is adjusted during the sequence of smaller time steps so that a successive lowering of the water table and the outflow occurs during an SZ time step This approach often overcomes numerical problems when large time steps are selected by the user If the drainage depth becomes zero during the calcu lations drainage flow stops until the water table rises again above the drain elevatio
164. bs wh dems Sad bed awe dawe 82 Overland Flow 2 408 4 e sce g Ge Hdd BOM we Pe ee ee ee 82 2 13 1 Manning number 2 5 a6 ivek ee es hbGe be ee Oe es Re 83 2 13 2 Detention Storage vay acy db oS ere Be a eee eee eo 84 2 13 3 Initial Water Depth 22 2 000 0085 85 2 13 4 Overland groundwater Leakage Coefficient 85 2 13 5 Separated Flow Areas 00220000 87 2 13 6 Overland Flow Zones 220220000 87 2 13 7 Dispersion coefficient along columns rows 89 2 13 8 Initial Mass per Species 22204 89 Unsaturated Zone ge ee he Se eH ed oe eee ee ee he eS 90 2 14 1 Soil Profile Definitions 93 2 14 2 Groundwater Depths used for UZ Classification 96 2 14 3 Ground Water Table aaau aaa 97 2 14 4 Partial automatic classification 97 2 14 5 Specified classification 20204 98 2 14 6 2 Layer UZ soil properties 8 0 99 2 14 7 ET Surface Depth 20 100 Groundwater Table 0 00000 eaeee 101 Saturated Zone 4 4244 06 be oe a hehe ee wwe dew Rowe 102 2 16 1 Interflow Reservoirs 0002 08 105 2 16 2 Baseflow Reservoirs 2 0002 08 106 2 163 Geological Units 2 hae kk ee hae ke Pe eee 108 2 16 4 Geological Layers 2 00 22005 109 2 16 5 GeologicalLenses 2 0002000 110 2 16 6 Lower Level Geological
165. by default when the water balance file is created The default Postprocessing name can be change to a more appropriate name Postprocessing items that are no longer needed can be deleted using the Delete button Use default Config file Unchecking the Use default Config file checkbox allows you to specify the location of a custom water balance Config file Development of cus tom water balance configuration files is described in detail in Making Custom Water Balances V p 141 Related items e Using the Water Balance Tool V 1 p 123 Postprocessing Detail For each item in the Postprocessing list above a new item will be added to the data tree If you expand the data tree each will have the following dia logue 188 MIKE SHE Postprocessings m Water balance Water balance type Total waterbalance Description pa water balance of the entire model setup M Output period Start date End date IV Use default period 1800701701 00 00 aj gt 2200701701 00 00 x M Output Timeseries Specifications Gutput time step hrs Type IV Use default output time step 0 Accumulated 7 Layer Output Specitications Layer aw layers Laver na 0 Sub Catchment Selection Single Cell Location Grid code 0 te 0 Y indew 0 r Output File Type Table Txt file B Water Balance Multiple postprocessings can be run on each water balance extraction More de
166. c Finally a combination of the Automatic classifica tion and the Specified classification is available If this option is cho sen an Integer Grid Code file must be provide see Partial automatic classification with the following grid codes In grid points where auto matic classification should be used the grid code 1 must be given In grid points where computation should be performed for all cells the grid code 2 must be given Bypass Flow Bypass flow is described in the Reference section under Simplified Macropore Flow bypass flow This flag simply determines whether it will be included or not If any soil zones include bypass flow the bypass option should be checked Related Items Unsaturated Flow Reference V 2 p 261 Richards Equation V 2 p 262 Gravity Flow V 2 p 273 Two Layer Water Balance V 2 p 275 Simplified Macropore Flow bypass flow V 2 p 280 Lumped UZ Calculations V 2 p 281 Coupling the Unsaturated Zone to the Saturated Zone V 2 p 282 92 MIKE SHE Unsaturated Zone ae 2 14 1 Soil Profile Definitions Profile ID Global Soil Profile phe C5 Testing eee UzSoi cas Testing DBASE Daisy _UzSoi CAS Testing DBASE Daisy _UzSoi r Bypass Const byp jos th 10 4 thr2 jo 3 Soil Profile Definitions Conditions when Unsaturated Flow selected in the Simulation Specification dialogue and Richards Equation or the Gravity Flow module selected for the
167. ce between the actual ponding depth and specified ponding depth The option is typically used for modelling irrigation of paddy rice 182 MIKE SHE Example database SX Thus e Moisture Deficit Start the maximum allowable moisture deficit below the specified reference level Irrigation will start at this level e Moisture Deficit Stop This is the minimum allowable moisture defi cit below the specified reference level If irrigation takes place it will stop at this level e Reference The reference moisture content It can be chosen as either saturation or field capacity e Prescribed This is the value used for the irrigation demand when User specified is chosen in the Irrigation Demand V 2 p 76 dia logue e Stress Factor This is the minimum allowed Actual ET Reference ET relationship This should be a value between 1 and 0 e Ponding Depth Irrigation will stop when the ponding depth reaches this value 7 2 Example database There is an example database MIKE_SHE_vege ETV in the Exam ples MIKE_SHE Karup directory under the installation MIKE SHE is by default installed in C Program Files DHI MIKEZero As the growing season of a given crop differs significantly depending on climatic region the user must always adjust the vegetation development to local conditions MIKE SHE Editors e 183 LAA ET Vegetation Properties Editor 184 MIKE SHE Example database Sx 8 WATER BALANCE
168. ces can become significant The damping function is controlled by a minimum gradient below which the damping function becomes active Experience suggests that you can get reasonable results with a minimum gradient between 0 0005 and 0 001 The default minimum gradient is 0 001 Higher val ues may lead to a divergence from the Mannings solution Lower val ues may lead to more accurate solutions but at the expense of numerical instabilities smaller time steps and longer simulation times For a detailed discussion of the damping function see the Low gradient damping function V 2 p 218 Overland River Exchange Calculation Overland flow will discharge into the MIKE 11 river link if the water ele vation in the cell is higher than the bank elevation The rate of discharge to the river is dictated by the Mannings calculation for overland flow How ever this flow is only one way that is from overland flow to the river If you want to include overbank spilling from the river to the overland grid cells then you must use the weir formula which provides a mechanism for water to flow back and forth across the river bank Note Whether or not to allow overbank spilling from the river to overland flow is made in MIKE 11 for each coupling reach If you do not allow overbank spilling in MIKE 11 then the overland river exchange is only one way but uses the weir formula instead of the Mannings formula for calculating the amount of exchange flow
169. cify whether you want All layers or just the Specified layer where you also must specify a layer number Sub catchment Selection If you extracted sub catchment data from the WM results then you must specify a subcatchment number or the name of the polygon for which you want the water balance for The combobox contains a list of valid ID num bers or polygon names Single Cell Location If you extracted the WM data by cell then if you are not creating a map output then you have to specify a cell location for which you want a water balance Output File If you are creating a table or time series water balance then you can write the output to either a dfsO file or to an ASCII file for import to MSExcel or other post processing tool If you are creating a map then the output will be to a dfs2 file with the same grid dimensions and spacing as the model grid If you are creating a chart then the output will be written to an ASCII file with a special format for creating the graphic Related items e Using the Water Balance Tool V p 123 The data tree for the results tab lists all of the calculated water balances The dialogue for each item includes the file name and an Open button 190 MIKE SHE Sane LEA that will open an editor for the file For ASCII output this will be your default ASCII editor usually Notepad For dfsO and dfs2 files the DHI Time Series Editor or Grid Editor will be opened For the chart outpu
170. come noticeable damping factor 1 0 2 os eee Thr 2 Thr Gradient dh Figure 13 3 Damping function for numerical stability at low gradients The damping function is controlled by a threshold gradient below which the damping becomes active The actual damping function is a pair of par abolic equations When the gradient reaches the threshold the following damping function is applied _ 2 eead 13 18 F 1 2 D Thr where Thr is the threshold value and dh is the gradient When the gradient reaches Thr 2 the damping function changes to 2 Pye a 2 13 19 which goes to zero as the gradient goes to zero You can get reasonable results with a threshold gradient between 0 0005 and 0 001 Higher values may lead to a divergence from the Mannings solution Lower values may lead to more accurate solutions but at the expense of numerical instabilities smaller time steps and longer simula tion times Technical Reference for Water Movement 219 a Overland Flow Reference 13 2 Simplified Overland Flow Routing The conceptual reservoir representation of overland flow in MIKE SHE is based on an empirical relation between flow depth and surface detention together with the Manning equation describing the discharge under turbu lent flow conditions Crawford and Linsley 1966 This was implemented in the Standford watershed model and in its descendants such as HSPF Donigian et al 1995 a
171. crops may develop different root distribution depending on the soil characteristics e Kc The crop coefficient The leaf area index and the root depth should be specified at the end of each crop stage The development of LAI and root depth between the specified values are then interpolated linearly by the model In addition to these parameters it is often necessary to supply the crop coefficient Kc which is used to adjust the reference evapotranspiration relative to the actual evapotranspiration of the specific crop By the FAO definition the reference evapotranspiration represents the potential evapotranspiration for a 8 15 cm high reference grass plane with ample water supply Most farm crops may differ from this in two ways 180 MIKE SHE Vegetation Database Items oe e In the early crop stages where LAI of the farm crop is lower than the LAI of the reference grass crop the evapotranspiration of the farm crop is less then the calculated reference evapotranspiration This is accounted for in the Kristensen amp Jensen ET calculation since a crop LAI is used as input Therefore for most field crops it is therefore not necessary to specify Kc values below 1 in the early crop stages e In the crop mid season the opposite situation may occur where crop potential evapotranspiration is larger than the calculated reference evapotranspiration of the reference grass crop This is not handled in the ET calculations and Kc value
172. ction V2 p 59 2 9 3 Infiltration Fraction Infiltration Fraction Conditions If Overland flow is simulated but unsaturated flow is NOT simulated dialogue Type Stationary Real Data EUM Data Fraction Units The Infiltration Fraction is the fraction of ponded water that infiltrates It is used when the unsaturated zone is not explicitly simulated Normally the unsaturated zone simulation calculates the amount of infil tration from overland flow since the amount of infiltration depends on the 59 a a Setup Data Tab water content of the upper most soil horizon If the soil is saturated then the infiltration will be low If the soil is very dry then the infiltration could be very high However the Net Infiltration Fraction is a stationary variable The only way to simulate the dynamic changes in the amount of infiltration is to simulate the unsaturated zone Note When MIKE 11 is used in MIKE SHE overland flow must always be included If you want to simulate strictly saturated flow coupled to MIKE 11 then you will need to use the Infiltration Fraction instead of the unsaturated flow The net recharge to the groundwater table Ren is Raet Pree Rainfall pes Infil sac 2 3 net where Prec is the actual precipitation Rainfall is the Net Rainfall Frac tion and Jnfil is the Infiltration fraction Related Items e Precipitation Rate V 2 p 58 e Infiltration Fraction V2 p 59 2 9 4
173. d then the unsaturated flow component which normally con trols surface subsurface exchange is no longer active In this case the overland flow module must exchange water with the saturated zone component directly The Overland groundwater exchange option allows you to specify an exchange coefficient to reduce the exchange of water between the overland flow and the saturated zone If the reduced contact in areas is chosen then a new item the Overland groundwater Leakage Coefficient V 2 p 85 must be specified Related Items e Separated Flow Areas V 2 p 87 e Overland groundwater Leakage Coefficient V 2 p 85 e Overland Flow Reference V 2 p 211 e Adding Overland Flow VJ p 46 e Coupling MIKE 11 and MIKE SHE VJ p 165 2 13 1 Manning number Manning number Condition when Overland Flow the Finite Difference method is selected in the Simulation Specification dialogue dialogue Type Stationary Real Data EUM Data ManningsM Units The Manning M is equivalent to the Stickler roughness coefficient the use of which is described in Overland Flow Reference V 2 p 211 83 a Setup Data Tab The Manning M is the inverse of the more conventional Mannings n The value of n is typically in the range of 0 01 smooth channels to 0 10 thickly vegetated channels This corresponds to values of M between 100 and 10 respectively Generally lower values of Mannings M are used for overland flow compared to
174. d 1 6 44 MIKE SHE Water Quality Simulation Specification LAA 2 3 Water Quality Simulation Specification wM AD Overland Flow OL A Iv River and Lakes El El Unsaturated Flow UZ oO fE Evapotranspiration ET E P Plant uptake Saturated Flow Sz iV Iv WQ Simulation Specification Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue In the WQ Simulation Specification dialogue you can select which com ponents of the hydrologic cycle will be included in the water quality simu lation The advection dispersion method calculates solute movements based on the intercell flows calculated in a water movement simulation Therefore only those components that are included in the water move ment solution can be selected Solute transport in surface water bodies is specified in and calculated by MIKE 11 If selected plant uptake by roots is treated as a solute sink in the unsatu rated zone Note In the initial release of the 2007 Release the advection dispersion module is only available for the saturated zone SZ and the overland flow OL components Solute transport in the unsaturated zone as well as sol ute sorption and decay will be added to the MIKE SHE user interface in a service pack in 2007 In the mean time if you need to simulate solute movement in the unsaturated zone or sorption and decay then you can specify the input files m
175. d effectively dry out the river If this occurs then the SZ solver will issue a warning and only this fraction of water will be removed which prevents rapid drying out of the river during a single time step Pre conditioned Conjugate Gradient Advanced Settings Advanced Settings V Gradual drain activation Recommended V Horizontal Conductance averaging between iterations Recommended Under relaxation No under relaxation Recommended Under telaxation with dynamic calculation of factor Under telaxation with constant factor 0 01 0 99 Gradual activation of SZ drainage To prevent numerical oscillations the drainage constant may be adjusted between 0 and the actual drain age time constant defined in the input for SZ drainage The option has been found to have a dampening effect when the groundwater table fluctuates around the drainage level between iterations and does not entail reductions in the drain flow in the final solution For the steady state solver and the transient solver the option is by default turned ON Horizontal conductance averaging between iterations To prevent potential oscillations of the numerical scheme when rapid changes between dry and wet conditions occur a mean conductance is applied by taking the conductance of the previous outer iteration into account By default this option is enabled for both steady state and transient simulations Under relaxation Under relaxation factors can be ca
176. d in Land Use dia logue dialogue Type Integer Grid Codes EUM Data Units Grid Code If there is insufficient water available to satisfy all of the irrigation demand then the irrigation areas can be prioritised In this case each area of the model can be assigned a priority number 1 highest priority All the areas with the highest priority will be irrigated first If there is suffi cient water after the first areas have been irrigated then the areas with the next highest priority will be irrigated However if there is insufficient water to completely satisfy the demand of a particular priority region all of the cells with priority value 1 for example then the water will be distributed to each of the cells based on either Equal Volume or Equal Shortage The choice of the two priority schemes is assigned in the main Land Use V 2 p 62 dialogue Equal Volume If the water is to be distributed based on equal volume then all cells with the same priority number will receive an equal amount of water regardless of their actual demand For example if there is a demand for 100 m of water in 10 cells but only 50 m is available then each cell will receive 5 m of water regardless of the actual demand Equal Shortage If the water is to be distributed based on equal shortage then all cells with the same priority number will receive an amount of water that satisfies an equal percentage of their actual demand For 78 MIK
177. defined with a 0 and areas with reduced contact are defined with a 1 Related Items e Inundation options by Flood Code V 1 p 173 e Bed Leakage V I p 176 e Overland Flow Reference V 2 p 211 MIKE SHE Overland Flow 2 13 5 Separated Flow Areas Separated Flow Areas Conditions when Overland Flow the Finite Difference method is selected in the Simulation Specification dialogue and Separated Flow Areas selected in the main Overland Flow dialogue dialogue Type Integer Grid Codes EUM Data Units Grid Code By specifying separated overland flow areas you can simulate areas that are separated by dikes or embankments Separated overland flow areas are defined by specifying a dfs2 Integer Grid Code file containing a unique code value for each flow area The model will then disable overland flow between grids with different flow codes Thus embankments can be simu lated by defining different flow codes on each side of the embankment Legal code values are 1 and higher Delete values are not allowed inside the model area Related Items e Overland Flow Reference V2 p 211 2 13 6 Overland Flow Zones Name Global Slope 0 Slope length 0 m Manning Number 0 m 1 3 s tention storage 0 mm Initial Depth 0 m Overland Flow Zones Conditions If Overland Flow the Subcatchment based method is chosen in the Simulation Specification dialogue dialogue Type Integer Grid Codes wit
178. dients for example in very flat areas will require very small time steps Likewise smaller grid spacing will also lead to smaller time steps 13 1 5 Boundary conditions The outer boundary condition for the overland flow solver is a specified head based on the initial water depth in the outer nodes of the model domain Thus if the water depth inside the model domain is greater than the initial depth on the boundary water will flow out of the model If the water depth is less than the initial depth on the boundary the boundary will act as a source of water 13 1 6 Low gradient damping function In flat areas with ponded water the head gradient between grid cells will be zero or nearly zero and numerical instabilities will be likely To dampen these numerical instabilities in areas with low lateral gradients the calcu lated intercell flows are multiplied by a damping function Essentially the damping function slows down the flow between cells You can think of the damping function as a function that increases the resistance to flow as the gradient goes to zero This makes the solution more stable and allows for larger time steps However the resulting gradients will be artificially high in the affected cells and the solution will begin to diverge from the Man 218 MIKE SHE Finite Difference Method a os nings solution At very low gradients this is normally insignificant but as the gradient increases the differences can be
179. dispersion coefficient m s not the disper sivity m Related Items e Solute Transport in Overland Flow V 2 p 344 2 13 8 Initial Mass per Species Initial Mass Condition when water quality for Overland Flow is selected in the Water Quality Simulation Specification dialogue dialogue Type Stationary Real Data EUM Data Units Mass per unit area The initial mass for overland transport is given as a surface concentration e g kg m This makes it easier to control the mass of solute introduced because you do not have to consider surface water depth Related Items e Solute Transport in Overland Flow V 2 p 344 e Initial Conditions V 2 p 347 in Overland Transport 89 LEA Setup Data Tab 2 14 Unsaturated Zone Calculation Column Classification Type 1 Automatic C 2 Specified calculation points 3 Calculated in all grid points 4 Partial automatic combination of 1 and 2 r Bypass Flow No C Yes There are three methods in MIKE SHE to calculate Unsaturated Flow e Richards Equation e the Gravity Flow and e the Two Layer Water Balance Both the Richards Equation method and the Gravity Flow use soil profiles that can have different soils at different depths Whereas the Two Layer Water Balance uses a uniform soil for the entire depth This leads to two distinct ways of entering UZ soil information in MIKE SHE each with a distinct set of parameter dialogues e asa soil pro
180. dity of the flow description in some situations such as on very steep hill slopes with contrasting soil properties in the soil profile MIKE SHE includes an itera tive coupling procedure between the unsaturated zone and the saturated zone to compute the correct soil moisture and the water table dynamics in the lower part of the soil profile There are three options in MIKE SHE for calculating vertical flow in the unsaturated zone e the full Richards equation which requires a tabular or functional rela tionship for both the moisture retention curve and the effective con ductivity e asimplified gravity flow procedure which assumes a uniform vertical gradient and ignores capillary forces and e asimple two layer water balance method for shallow water tables The full Richards equation is the most computationally intensive but also the most accurate when the unsaturated flow is dynamic The simplified gravity flow procedure provides a suitable solution when you are prima rily interested in the time varying recharge to the groundwater table based on actual precipitation and evapotranspiration and not the dynamics in the unsaturated zone The simple two layer water balance method is suitable when the water table is shallow and groundwater recharge is primarily influenced by evapotranspiration in the root zone Each cell in the model is assigned to a soil zone for which a soil profile is defined In this way the unsaturated zone can be
181. e The unsaturated zone profiles should extend below the maximum depth of the water table in top SZ calculation layer or to the bottom of uppermost SZ calculation layer If the top layer of the SZ model dries out then the UZ model usually assumes a lower pressure head boundary equal to the bottom of the uppermost SZ layer For more detailed information on the UZ SZ bottom boundary see Lower Boundary p 269 16 6 3 Evaluation of the UZ SZ Coupling The WM_Print log file generated by MIKE SHE should be reviewed after each simulation to evaluate the performance of the UZ module If the user specified maximum UZ iterations is exceeded an excessive number of times and there are no problems with the soil data used in the UZ module the UZ and SZ time step should be evaluated Sometimes it is possible to reduce the number of times the maximum UZ iterations is exceeded by making the UZ and SZ time steps more similar Typically the SZ to UZ time step ratio should be no larger than four It is also useful to save the value of E as a grid series output or as a detailed time series output at critical locations These plots can be used to determine if there are locations or periods of time during the simulation where the Ecum term exceeds Emax This can occur if e the water table drops below the first SZ calculation layer positive value e the water table rises above the top of the first SZ calculation layer neg ative value e the vertical
182. e gives Ax h t Z Qourl lt 2Q 1 At 13 15 remembering that 7 iAx and i is the net input into overland flow net rainfall less infiltration If necessary during an iteration these calculated outflows are reduced to satisfy the equal sign of 13 15 216 MIKE SHE Finite Difference Method a oe To ensure that the inflows 2Q have been summed before calculating Qo the grid squares are treated in order of descending ground levels during each iteration 13 1 4 Explict Numerical Solution The explicit solution is different from the SOR solution in the sense that there is no iterative matrix solution In other words the exchange flows between every cell and to the river are simply calculated based on the indi vidual cell heads However the explicit solution is much more restrictive in terms of time step For the explicit solution to be stable the flow must be slow relative to the time step For example a flood wave cannot cross a cell in one time step So this leads to the following 3 step calculation process for the explicit solution of the overland flow 1 Calculate all flow rates and discharges between cells and between the overland cells and river links based on the current water levels 2 Loop over all the cells and calculate the maximum allowed time step length for the current time step based on the following criteria Courant criteria see next section Cell volume criteria the volume in the c
183. e uppermost UZ node e If the available water exceeds the deficit in the top UZ node then the head boundary is used e If the available water is less then the deficit in the top UZ node then a flux boundary is used If the head boundary is used then when the solution is found the amount of infiltration is compared against the available amount of infiltration If the available infiltration is exceeded then the solution is repeated with the flux boundary If the flux boundary is used then the available water for infiltration is divided by the time step length to get the infiltration rate When the solu tion is found the water content in the uppermost UZ node is compared to the saturated water content If the saturated water content was reached or exceeded then the solution is repeated using the head boundary The solution is restricted to a maximum of one repeat in each time step to prevent an infinite loop Lower Boundary In most cases the lower boundary is a pressure boundary that is deter mined by the water table elevation Then Eq 16 21 consists of N M equations If node M is the first node below the water table then Ey 9 Fy watish 16 23 where h is the distance between the water table and node M Noted that Wy is independent of yy since Ey 0 If the UZ model is not coupled to a SZ model then the lower boundary is automatically converted from a pressure head boundary to a zero flux Technical Ref
184. e ability of the soil to conduct water upwards is limited Thus the factors AROOT and root depth are important parameters for esti mating how much water can be drawn from the soil profile under dry con ditions of total ET 0 10 20 30 40 e T 50 8 E e AROOT 2 0 a 100 a AROOT 1 0 z AROOT 05 om AROOT 0 1 E 150 2 Maximum Root Depth 200 cm 200 Figure 15 4 Fraction of ET extracted as a function of depth for different values of AROOT Technical Reference for Water Movement 249 LAA Evapotranspiration Reference of total ET 0 5 10 15 20 25 0 E i 50 S T 53 gt 100 z AROOT 1 0 3 S 150 a Maximum Root g Depth 200 cm z e Maximum Root 200 Depth 100 cm Figure 15 5 Fraction of ET extracted as a function of depth for different maxi mum root depths 15 1 5 Soil Evaporation Soil evaporation E occurs from the upper part of the unsaturated zone and consists of a basic amount of evaporation E f3 9 plus additional evaporation from excess soil water as the soil saturation reaches field capacity This can be described by the following function E E f 9 E Ear Ep 8 Fa fi LAD 15 8 where E is the potential evapotranspiration E is the actual transpiration Eq 15 3 f LAD is from Eq 15 4 and the functions f3 9 and f 0 are given by C for O Ow f 9 Coe for 0 lt 0 lt 0y w 0 for 0 lt 0 o Ow
185. e boundary cells propor tional to the grid size of the flow surfaces constant in MIKE SHE Notes on the PCG solver The discharges to from the internal cells are updated at the start of each outer iteration and added to the Right Hand Side of the PCG solver The Technical Reference for Water Movement 297 Saturated Flow Reference discharges are distributed to the X Y flow velocities for results storing at the end of each SZ time step Notes on the SOR solver The discharges to from the internal cells are updated at the start of each iteration and used as point source sink terms in the solution The dis charges are distributed to the X Y flow velocities for results storing at the end of each SZ time step Saturated Zone Drainage The MIKE SHE allows for flow through drains in the soil Drainage flow occurs in the layer of the ground water model where the drain level is located In MIKE SHE the drainage system is conceptually modelled as one big drain within a grid square The outflow depends on the height of the water table above the drain level and a specified time constant and is computed as a linear reservoir The time constant characterises the density of the drainage system and the permeability conditions around the drains The drainage option may not only be used to simulate flow through drain pipes but also in a conceptual mode to simulate saturated zone drainage to ditches and other surface drainage
186. e drain flow will be routed to the nearest boundary cell 2ith the same Drain Code value 127 Setup Data Tab 2 If there are no boundary cells with the same Drain Code value the drain flow will be routed to the cell with the lowest drain level that has the same Drain Code value which may create a lake One method that is often used is to specify only one Drain Code for the entire model area e g Drain Code 1 Thus all grids can drain and any drain flow is routed to the nearest river link If there are no rivers the drain flow will be routed to the nearest boundary If you want to route all drain flow to the boundaries instead of the rivers a negative drain code can be specified for the entire area e g Drain Code 1 Related Items e Saturated Zone Drainage V 2 p 298 e Drainage with the SOR Solver V 2 p 306 e SZ Drainage to Specified MIKE 11 H points VJ p 151 e Using MIKE SHE with MOUSE VJ p 181 2 16 26 Option Distribution Option Distribution Conditions always when Surface Drainage active AND when the Distributed drainage option is used dialogue Type Integer Grid Codes EUM Data Units Grid Code Valid Values 1 2 3 and 4 only The drain type distribution is used to distinguish areas of the model where different drainage options are used Code 1 Drainage in grid cells with a value of 1 is routed downhill based on the value of the drain level specified in Drain Level data item Code
187. e ee ote eee 34 BasefloOow 316 SZ vii hat aoe Powe eae Se 40 Baseflow Reservoirs 106 UZ etn Bentinck enue ene dete ee 39 Bathymetry 82 Coupling Boundary condition MIKE SHE and MIKE 11 228 Available 119 121 Unsaturated Zone Saturated Zone Internal 2 121 282 Outer 2 2 eGet eta Sate 32 118 Coupling Procedure Specification 118 Unsaturated Zone Saturated Zone Boundary Conditions 284 3D Finite Difference Method 296 Crop Coefficient 255 Boundary conditions 218 Cross section Richards Equation 268 River Link 231 boundary conditions Current Layer 26 Dirichlet 296 Fourier s kame wie amp led en es 296 D Neumann 296 Database Bypass Flow 92 Example 183 Dead Zone Storage 315 Cc Detention Storage 84 Calculation Diffusive Wave Approximation 211 Baseflow 316 Drain Codes 44 6 wwe aoe be ew 127 Dead Zone Storage 315 Drain Level 125 Exchange Flows 239 Drain Time Constant 126 Interflow 313 Drainage Interflow Percolation 315 3D Finite Difference Method 298 Calculations PCG Solver 299 Lumped UZ 281 SOR Doa aapa ara a S 306 382 MIKE Zero Index E Infiltration Fraction 59 ET Initial Conditions
188. e groups which regulate interception soil evaporation and plant transpiration respectively The amount of soil water which can be intercepted by the vegetation can opy is determined by multiplying the interception capacity Cinn by the LAI Cins depends on the surface characteristics of the vegetation type The units of C are L but they should be interpreted as L area of leaves ground area A typical value is 0 05 mm The calculation of soil evaporation contains two components the basic soil evaporation which occurs regardless of soil dryness at moisture con tents in the range Ow 2 Ow Op and enhanced soil evaporation at mois ture contents above 2 0w Op The fraction of the potential evapotranspiration which is always allocated to the basic soil evapora tion is determined by C2 In the two layer soil model described by Kris tensen amp Jensen 1975 this value was found to be 0 15 For dynamic simulation using the unsaturated zone description in MIKE SHE a value of 0 2 was however found to give better results Miljgstyrelsen 1981 Jensen 1983 The transpiration from the vegetation is regulated by two parameters C1 is the slope of the linear relation between LAI and Ea Ep which deter mines at which LAI the actual evapotranspiration equals the potential evapotranspiration at ample water supply A typical value of C1 is 0 3 C3 regulates the influence of water stress on the transpiration process and may d
189. e is only used if you have selected the sub catchment water balance type You can specify a delete value to exclude areas from the water balance The grid spacing and dimensions in this dfs2 file must match exactly the model grid You can also specify a polygon shape file to define the sub catchment areas The shape file may contain multiple polygon with the same or dif ferent codes Further the shape file length units do not have to be the same as the model length units e g feet vs meters Gross files The pre processor extracts the water balance data from the standard MIKE SHE output files and saves the data in a set of gross files The file names of the gross files is built up from the project name and prefix specified here The default value is normally fine Related items e Using the Water Balance Tool V 1 p 123 8 2 Postprocessings After you have extracted the water balance data from the MIKE SHE results files then you can switch to the post processing tab Here you can create any number of individual water balances by simply clicking on the Add item icon and specifying the water balance parameters in the parame ter dialogue MIKE SHE Editors e 187 Water Balance Editor 8 2 1 Altemative config file IV Use default Config file C Program Files DHINMIKEZero bin MShe_Wbl Contig pfs a C i n a eee Total Accumulated Fisher Creek Incremental A single Postprocessing item is created
190. e model inactive It works by assigning a hydraulic conductivity of zero to the cells if the simulation is transient or a value of 10 5 if the simulation is steady state Note though that this method means that in MIKE SHE Saturated Zone Ss the pre processed data you will see the inactive cells show up in the maps of hydraulic conductivity rather than in the maps of boundary conditions Also note that since the inactive cells are actually active cells with zero conductivity the results will also include head values in these points Sub surface drainage and MODFLOW Rivers These two boundary conditions are not yet available Related Items e Saturated Flow Reference V 2 p 289 e Boundary Conditions V2 p 296 2 16 21 Initial concentration 2 16 22 Drainage Initial Concentration dialogue Type Stationary Real Data EUM Data Units Concentration There is an initial concentration item for each computational layer Under each initial concentration item there is one sub item for each active spe cies The initial concentration is used by the MIKE SHE Water AD engine as the starting concentration for the Water quality simulation Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Initial Conditions V 2 p 338 Drainage Option Drainage routed downhill based on adjacent drain levels Drainage routing based on grid codes Distributed drainage options Drainage not
191. e observation data If this is checked then a dfsO file can be specified that includes observation points The observation points are automatically plotted along with the results in the HTML plot on the Results tab The dfsO item is selected in the file browser dialogue The Edit button opens the specified dfsO file and the New button can be used to create a new dfs0O file with the correct item type etc and at the same time import data from an Excel spreadsheet Importing data Detailed MIKE SHE Time Series data can be imported directly into the Detailed MIKE SHE Time Series dialogue using the Import button The data file must be a tab delimited ASCII file without a header line The file must contain the following fields and be in the format specified below Name gt DataTypeCode gt NewP lot gt X gt Y gt Depth gt UseObsdata gt dfsOfile name gt dfsOItemNumber where the gt symbol denotes the Tab character and Name is the user specified name of the observation point This is the name that will be used for the time series item in the Dfs0 file created during the simulation DataTypeCode This is a numeric code used to identify the output data type A list of available Data Type Codes can be found in Output Items V 1 p 87 139 LEA Setup Data Tab NewPlot This is a flag to specify whether a new detailed time series HTML plot will be created on the Results Tab 0 the output will be added to the previous plot 1 Cr
192. e precipitation However semi arid climates you may impact your water balance Technical Reference for Water Movement 245 LEA Evapotranspiration Reference 15 1 4 Plant Transpiration The transpiration from the vegetation Ean depends on the density of the crop green material i e the leaf area index LAI the soil moisture con tent in the root zone and the root density Thus Eg fi LAD f 8 RDF E 15 3 where Eis the actual transpiration LT f LAJ is a function based on the leaf area index f2 0 is a function based on the soil moisture content in the root zone and RDF is a root distribution function Si LAD The function f LAI expresses the dependency of the transpiration on the leaf area of the plant by see Figure 15 1 fi LAI C C LAI 15 4 where C and C are empirical parameters fA9 The second function f gt 6 is given by G _ Orc 8 poi 15 5 where 0pc is the volumetric moisture content at field capacity Owis the volumetric moisture content at the wilting point O is the actual volu metric moisture content and C3 is an empirical parameter LT As illustrated in Figure 15 2 higher values of C3 will lead to higher values of transpiration which means that the soil will dry out faster assuming all 246 MIKE SHE Kristensen and Jensen method a oe other factors constant In a simulation the actual transpiration will d
193. e time n to n m the column has lost V mm of water the light grey shaded area and gained V3 mm the dark shaded area The changes calculated by the UZ module for the areas V and V repre sent a redistribution of water in the unsaturated zone to obtain an equilib rium moisture profile within the soil column Comparing the equilibrium moisture content and the moisture content at UZ time n in Figure 16 7a shows that the moisture content is too high in the upper portions of the soil column This should result in downward flow in the unsaturated zone loss of soil moisture in area V increased soil moisture in area V gt and a rise in the water table However the SZ module uses a constant specific yield Sy defined for each grid cell in each calculation layer On the other hand the UZ can have a unique S value for each UZ node which may differ from the S value used by the SZ Thus mass balance errors can occur in exchange calculations between the two modules A mass conservative solution is achieved by using a step wise adjustment of the water table and recalculation of the UZ solution until the area of V1 and V2 are equal see Figure 16 7b The procedure to deal with this mass balance error consists of a bookkeep ing of the accumulated mass balance error Ecum for each UZ column and the upper SZ calculation cell associated with the column on a cell by cell basis If Egum exceeds a user specified value Emax the UZ coupling Tec
194. e treat as fixed concen tration cells with a concentration equal to the initial concentration A pre scribed time varying concentration boundary can be specified at any internal node Prescribed flux concentration can be specified on the catchment boundary as well as in any cell inside the model area The flux concentration at the catchment boundary can be constant or time varying Sinks can either extract pure water concentration equal to zero or water with the current concentration Soil evaporation is the only sink which removes water with a concentration equal to zero Sinks where the con centration is equal to the actual solute concentration in the grids include pumping wells drains and MIKE 11 nodes Referring back to Figure 19 1 you should note that 338 MIKE SHE User s Guide Solute Transport in the Saturated Zone LAA e If UZ transport is included the upper boundary for the groundwater transport is the exchange of mass with the UZ component Infiltration from and to the unsaturated zone is treated as a source or sink term However if the UZ flow had a shorter storing time step than the SZ flow the concentration in the top layer of the SZ transport is updated at the UZ time step e If UZ bypass flow was specified mass is transferred directly from the overland to the groundwater with the flux equal to bypass flow multi plied with the concentration on the overland e Direct exchange between OL flow and SZ
195. e values and the proximity of rivers and boundaries Then whenever drainage is generated in a cell the drain water will always be routed to the same destination cell Drainage to local depressions and boundary All cells with the same positive code are drained to the cell with the same numeric negative code Drainage to river All cells with the same positive code are drained to the cell with the same numeric negative code Related Items e Groundwater Drainage V 1 p 53 e Drainage V 2 p 123 e Drain Level V 2 p 125 e Drain Time Constant V 2 p 126 e Drain Codes V 2 p 127 e Option Distribution V2 p 128 3 2 GeoScene3D M GeoScene settings Vertical exaggeration Factor 30 Transparency of surfaces 0 3 Show computational layers Show geological layers F Show Lenses Launch GeoScene3D 152 MIKE SHE GeoScene3D Se The GeoScene3D dialogue provides a link to the GeoScene3D program for viewing the preprocessed model setup The preprocessed data does not include any transient or time data So GeoScene3D only shows stationary data Vertical exaggeration factor In most models the lateral extent is sev eral orders of magnitude greater than the vertical extent Thus without a vertical exaggeration factor the model view will be too thin to be useful A vertical exaggeration of 10 to 30 will typically give you a good looking model that accentuates the vertical differences
196. eate a new plot X Y This is the X Y map coordinates of the point in the same EUM units ft m etc as specified in the EUM Database for Item geometry 2 dimensional see EUM Data Units Depth This is the depth of the observation point below land surface for subsurface observation points The value is in same EUM units ft m etc as specified in the EUM Database for Depth Below Ground see EUM Data Units A depth value must always be included UseObsData This is a flag to specify whether or not an observation file needs to be input 0 No 1 Yes dfsOfile name This is the file name of the dfsO time series file with observation data The path to the dfsO file must be relative to the direc tory containing the MIKE SHE she document The dfsO extension is added to the file name automatically and should be not be included in the file name For example Time Calibration GroundwaterObs refers to the file GroundwaterObs dfsO located in the subdirectory Time Calibration which is found in the same directory as the she model document dfsOItemNumber This is the Item number of the observation data in the specified DFSO file The following is a simple example with three MIKE SHE observation points where the file name is obsdata dfsO Obs_1 gt 20 gt 1 gt 234500 gt 456740 gt 0 gt 0 gt time obsdata gt 1 Obs_2 gt 15 gt 1 gt 239700 gt 458900 gt 10 gt 1 gt time obsdata gt 2 Obs_3 gt 16 gt 0 gt 241
197. ecause the tension term can yield an upwards flow from the groundwater table which is not physically possible when the upper SZ layer is dry UZ model SZ top layer Water SZsecond Ws table layer In the first and last cases above the flux out the bottom of the UZ column is added as a flux boundary condition to the uppermost SZ node 16 1 3 Initial Conditions The initial conditions for y are generated by MIKE SHE assuming an equilibrium soil moisture pressure profile with no flow The equilibrium profile is calculated assuming hydrostatic conditions as illustrated in Fig ure 16 2 The pressure decreases linearly from zero at the groundwater table to ypc when the moisture content reaches the field capacity and is then remains constant for all nodes above this point The assumption is that the flow is almost zero at moisture contents below the field capacity Technical Reference for Water Movement 271 LAA Unsaturated Flow Reference PRESSURE r DISTRIBUTION _ MOISTURE DISTRIBUTION View 0 Yo Figure 16 2 Illustration of initial soil moisture profile and pressure head profile 16 1 4 Sources and sinks Richards Equation Eq 16 7 includes a source sink term for each com putational node These sink terms are calculated from the root extraction due to transpiration in the upper part of the unsaturated zone The integral of the root extraction over the entire root zone depth equals
198. ecomes dt h h iE 17 52 y In general during a time step the water level may cross one or more of the pumping or the baseflow thresholds If this occurs the program uses an iterative procedure to split the time step into sub time steps and applies the appropriate formulation to each sub time step 17 2 7 UZ Coupling A feedback mechanism to the unsaturated zone has been included in the module to model a redistribution of water in favour of evapotranspiration from the low wetland areas located adjacent to most rivers Water is redistributed from the linear reservoirs to the unsaturated zone model in the lowest topographical zone of the subcatchment if there is a water deficit in the root zone This deficit is called the Field Moisture Def icit FMD and is calculated as the amount of water required to bring the root zone back up to field capacity Thus n Rootdepth FMD rc 0 dz X Orc 8 Az 17 53 i l where Orc is the moisture content at field capacity O is the moisture con tent in the root zone n is the number of UZ cells in the root zone and Az is the height of the UZ cell Now the amount of water that is available from the linear reservoirs to be redistributed to the unsaturated zone is calculated as a fraction of the base flow S available a Op iSy1 i U2 acl dt Op Syo UL pract dt 17 54 where UZfac is a specified fraction of the baseflow that is allowed to recharge the unsaturated zone
199. ecrease more quickly for larger values of C3 MD t3 Lal Figure 15 1 The function f versus LAI 6 C3 20 mm day Be Sy Figure 15 2 The soil moisture function f2 0 for constant C3 20 mm day and var ying Ep left and for constant Ep 4 mm day and varying C3 right Root Distribution Function RDF Water extraction by the roots for transpiration varies over the growing sea son In nature the exact root development is a complex process which depends on the climatic conditions and the moisture conditions in the soil Thus MIKE SHE allows for a user defined time varying root distribution determined by the root depth time varying and a general vertical root density distribution see Figure 15 3 Technical Reference for Water Movement 247 Evapotranspiration Reference Rost depth m 1 5 1C U5 o l m Fercentese ol rest Depth m Figure 15 3 Root distribution in time and with depth The root extraction is assumed to vary logarithmically with depth by see Figure 15 3 logR z logR AROOT z 15 6 where R is the root extraction at the soil surface AROOT is a parameter that describes the root mass distribution and z is the depth below ground surface L The value of the Root Distribution Function RDF in each layer is then calculated by dividing the amount of water extracted in the layer by the total amount of water extracted by the roots Thus RDF
200. ed in each node but the routing is based only on the code values in the drain code file The drain level also determines from which layer the drain water will be extracted Related Items e Time varying drainage parameters VJ p 154 e Saturated Zone Drainage V 2 p 298 e Drainage with the SOR Solver V 2 p 306 e SZ Drainage to Specified MIKE 11 H points V 1 p 151 e Using MIKE SHE with MOUSE V 1 p 181 2 16 24 Drain Time Constant Drain Time Constant dialogue Type Stationary Real Data EUM Data Units Leakage Coefficient Drain Time Constant Drainage flow is simulated using an empirical formula which requires for each cell a drainage level and a time constant leakage factor Mathe matically the time constant is exactly the same as a leakage coefficient it is simply a factor that is used to regulate how quickly the water can drain A typical time constant is between le 6 and le 7 1 s Related Items e Time varying drainage parameters VJ p 154 e Saturated Zone Drainage V 2 p 298 e Drainage with the SOR Solver V 2 p 306 e SZ Drainage to Specified MIKE 11 H points VJ p 151 e Using MIKE SHE with MOUSE V 1 p 181 126 MIKE SHE Saturated Zone 2 16 25 Drain Codes Drain Codes dialogue Type Integer Grid Codes EUM Data Units Grid Code If the drainage routing is specified by Drain Codes a grid code map is required that is used to link the drain flow producing c
201. ed zone component and the groundwater compo nent Figure 19 2 shows how the simulation time steps can be controlled solely by the storing time step in the flow simulation Solute sources and the storing of data in the different components influ ences the time step For example in Figure 19 2 a SZ source requires that all components have a break when the source starts SAT ZONE COMPONENT UNSAT ZONE COMPONENT CHANNEL COMPONENT OVERLAND COMPONENT START READING OF READING OF READING OF TME WM RESULTS WM RESULTS WM RESULTS 0c uz ET S82 SAT ZONE COMPONENT UNSAT ZONE COMPONENT CHANNEL COMPONENT OVERLAND COMPONENT START STORAGE OF SOURCE SOURCE TIME SZ RESULTS FOR RIVER FOR SZ SOURCE SOURCE FOR UZ FOR OVERLAND Figure 19 2 An example calculation sequence for solute transport in MIKE SHE Time step limitations For each component the maximum allowable time step is determined by the advective and dispersive Courant number 328 MIKE SHE User s Guide Solute Transport in the Saturated Zone LA The advective Courant number in the x direction is defined as T v At 19 1 Gei 19 1 and the dispersive Courant number I is defined as roy 19 2 2 19 2 Ax The limitations are different in each flow component and will be described in more detail under the respective flow component sections You can also specify a maximum time step for each component as well as
202. eight functions so that the mass transports can be calculated in one step 19 4 3 Initial Conditions The initial concentration can be a fully distributed concentration field e g measured or simulated concentrations at a certain time The unit for the overland concentration is mass area If there is a flux of water into the model area from boundary points the flux concentration in these points will be constant in time and equal to the Technical Reference for Water Quality 347 LEA Advection Dispersion Reference initial concentration if the flux concentration at any of these points is not specified as a time varying source concentration 19 4 4 Source Sinks Boundary Conditions and other Exchanges Dissolved solutes can be added to the overland flow via precipitation or from discharging groundwater Alternatively the solute can be added directly as a spatially distributed source on the land surface As indicated in Figure 19 2 the overland transport component exchanges mass with the MIKE 11 the unsaturated zone and the saturated zone In the case of exchange to MIKE 11 the solute mass is simply added as a source term to MIKE 11 Similarly infiltration is added as a source in the unsaturated zone Exchange directly to the saturated zone can occur if by pass flow is allowed in which case the bypass flow concentration is the same as the concentration in the overland flow Exchange to overland flow from the saturated zo
203. ell connected to the aquifer In this case the majority of the groundwater surface water exchange occurs through the banks of the river and decreases to zero towards the centre of the river However in the case of losing streams separated from the groundwater table by an unsaturated zone the majority of the infiltration occurs vertically and not through the river banks In this case the horizon tal infiltration area may be too small if the MIKE 11 bank elevations are much higher than the river level This can be compensated for by either choosing a lower bank elevation or by increasing the leakage coefficient There are three variations for calculating da e Ifthe water table is higher than the river water level da is the saturated aquifer thickness above the bottom of the river bed Note however that da is not limited by the bank elevation of the river cross section which means that if the water table in the cell is above the bank of the river da accounts for overland seepage above the bank of the river e If the water table is below the river level then da is the depth of water in the river e If the river cross section crosses multiple model layers then da and therefore C is limited by the available saturated thickness in each layer The exchange with each layer is calculated independently based on the da calculated for each layer This makes the total exchange inde pendent of the number of layers the river intersects 23
204. ell divided by the flow rate River link volume criteria the volume in the river link divided by the flow rate River bank criteria the exchangeable volume in the river link based on the river bank elevation divided by the flow rate In most cases the Courant criteria is the critical criteria for the maxi mum time step with the Cell volume criteria sometimes being critical The River link and River bank criteria are less commonly critical but may become critical when the river is very shallow 3 Calculate the actual flows between the all the cells and to from the river links using the maximum allowed time step and update all the cell water depths Courant criteria Courant number C represents the ratio of physical wave speed to the grid speed and is calculated as dQ _dA_1 dQ dt C dx Tu Th aoe 13 16 dt Technical Reference for Water Movement 217 a Overland Flow Reference where do is the change in flow rate dA is the change in cross sectional area and oh is the change in water level For a stable explicit solution the courant number must be less than one Solving for the time step yields _ dh 2 Ax gt 13 1 dO ee 13 17 At where At is the time step and Ax is the cell width The differential term in 13 17 is the inverse of the derivative of the Man nings equation 13 13 with respect to h which goes to zero as the gradi ent approaches zero Thus very low gra
205. ells to recipient grid cells The drain levels are still used to calculate the amount of drain flow produced in each node but the routing is based only on the code values in the drain code file The Drain Code can be any integer value but the different values have the following special meanings Code 0 Grid cells with an Drain Code value of zero will not produce any drain flow and will not receive any drain flow Code gt 0 Grid cells with positive Drain Code values will drain to the nearest river boundary or local depression in the drain level in that priority located next to a cell with the same Drain Code value Thus if a grid cell produces drainage 1 If there are one or more cells with the same drain code next to a river link then the drain flow will be routed to the nearest of these cells 2 If there are no cells with the same Drain Code located next to a river link then the drain flow will be routed to the nearest boundary cell with the same Drain Code value 3 If there are no boundary cells with the same Drain Code value the drain flow will be routed to the cell with the lowest drain level that has the same Drain Code value which may create a lake Code lt 0 Grid cells with negative Drain Code values will drain to either a boundary or a local depression in that order Thus if a grid cell pro duces drainage 1 If there are no cells with the same Drain Code located next to a river link then th
206. ement simulation is similar in both modules Therefore you may find MIKE SHE AD Technical Reference a good source of additional informa tion The PT module is typically used to delineate capture zones upstream zones and to determine groundwater age 21 1 Governing equations The transport of solutes and particle tracking in the saturated zone is gov erned by the advection dispersion equation which for a porous medium with uniform porosity distribution is formulated as 4 uc V D Ve 0 21 1 where c is the solute concentration t is time u is the groundwater pore velocity and D is the dispersions tensor In the particle model a large number of particles are moved individually in a number of time steps according to contributions from advective and dispersive transport A par ticle mass is associated to each particle which means that the number of particles in a cell corresponds to a solute concentration For isotropic conditions in the soil matrix the displacement of a particle is described by the following equation Thompson et al 1987 Xtar Xp tn UX w tn V D X w te Att BO w tn Zpnaivdt L2 369 oa Particle Tracking Reference where X is the particle co ordinates Ar 1 1 is the time step length Z 1 18 a vector containing three independent random numbers equally distributed in the interval and B R B 21 3 where u u u ue uu u p Blu
207. en the two reservoirs is determined by the faction give in the Baseflow Reservoirs V 2 p 106 dialogue If the demand from one of the 72 MIKE SHE Land Use Ss reservoirs exceeds the available water the pumping will be reduced The pumping rate at the other reservoir will not be increased to compensate Also in the Linear Reservoir method the specified max depth to water for the actual command area and source is used In other words it is not using the threshold depth for pumping in the baseflow reservoir menu Pumping is allowed when the depth to the water table is less than the spec ified threshold value at the start of the time step Shallow Well Source Shallow well source Max depth to water 8 m Top of screen 0 m Max rate 10 25 me s Bottom of Screen 116 25 m In many cases farmers have several shallow wells for irrigation most of which may not be mapped exactly Especially in regional scale models each grid cell could thus contain many shallow groundwater wells In such cases the Shallow Well source can be used to simply extract water for irri gation from the same cell where it is used without having to know the exact coordinates of the wells By specifying this option one well is placed in each cell of the command area Note A cell i j layer containing a shallow well cannot also have a sin gle well specified in the same cell i e the same cell and layer Max depth to water
208. ence an image file in which case either a bpw or a bmpw file is created that contains the origin coordinates and some scaling informa tion Image Styles The Image Style is related to the way the pixel colours are averaged or not averaged in overlying grids and images The Image Style variables have little influence on the image display when the image is displayed in the Background However in the Foreground the Image style is very important The best results are obtained with the Blend Colours selection in which case the Transparent colour option is not used 22 MIKE SHE Display a a 2 1 3 Grid Overlays IV Display Grid File C S Testing NRSaby ET Surface Depth dfs2 a Transparency 38 v If you want to add a static dfs2 grid on the map view then you should add a Grid Overlay If you add a time varying dfs2 file the program will not object but only the first time value will be displayed If you add a dfs2 file containing multiple items such as a results file you can select the grid item to display from within the file browser Transparency This is used to control the way pixel colours are averaged for displaying images that overlay one another 23 LEA Setup Data Tab 2 1 4 Shape Overlays Display Shape File ltem C 45 Testing NRSaby TIME Pejlinger alle_pejlinger shp SE POINT_NUMB Parameters for Points p Point color B Point style Po
209. ep Accumulated V 1 p 247 If you use an amount then the EUM Data Units must be Rainfall and the time series must be Step Accumulated V 1 p 247 The Precipitation Rate item comprises both a distribution and a value The distribution can be either uniform station based or fully distributed If the data is station based then for each station a sub item will appear where you can enter the time series of values for the station If Snowmelt is included and the Air Temperature is below the Threshold melting temperature then the precipitation will accumulate as snow Related Items e Creating Time Series in MIKE SHE V 1 p 243 e Working with Spatial Time Series V 1 p 245 e Time Series Types VJ p 246 58 MIKE SHE Precipitation a oe 2 9 2 Net Rainfall Fraction Net Rainfall Fraction Conditions If Evapotranspiration is NOT selected dialogue Type Stationary Real Data EUM Data Fraction Units The Net Rainfall Fraction is the fraction of rainfall that is available for infiltration and overland flow It is used to account for leaf interception and evapotranspiration when ET is not explicitly simulated The net recharge to the groundwater table R is Raet Prec Rainfall es Infil 2 2 frac where Prec is the actual precipitation Rainfall is the Net Rainfall Frac tion and Jnfily is the Infiltration fraction Related Items e Precipitation Rate V2 p 58 e Infiltration Fra
210. epend on the soil type with higher values for light soils than for heavier soils The influence of soil dryness is reduced when C3 is increased In Kristensen amp Jensen 1975 a value of 10 mm was found for loamy soils For simulations with the unsaturated zone description in MIKE SHE a value of 20 mm was found more appropriate Milj sty relsen 1981 Jensen 1983 The root distribution in the soil is regulated by the Aroot parameter The value of Aroot may depend on soil bulk density with higher values for soils with high bulk density where root development may be more MIKE SHE Editors 179 ET Vegetation Properties Editor 7 1 4 restricted than for soils with low bulk density A typical value is 1 at which 60 of the root mass is located in the upper 20 cm of the soil at a root depth of 1 m Lower Aroot values decrease this fraction and give a more even root distribution Note The C1 C2 C3 and AROOT parameters are only used in the Rich ards Equation and Gravity Flow methods and not in the 2 Layer UZ method Vegetation Development Table For each crop stage three vegetation parameters need to be specified e LAI The Leaf Area Index which is the Area of leaves Area of the ground can vary between 0 and 7 depending of the vegetation type e Root The Rooting Depth of the crop It will normally vary over the season Consideration about the soil type should be taken because some
211. er ts Item type Layer Thickness la Expression jas Example Level Level2 Conduc lt Back Cancel Heb In the first part of this dialogue you need to specify the files and variable names used in the mathematical operation In the second part you must specify the output file name including the dfs2 file extension as well as the EUM unit type and units for the result ing file see EUM Data Units Although the EUM list is alphabetical the list of EUM data types is very long as it includes all of the available EUM types for all of the MIKE Zero products If you are trying to create a par ticular input type for MIKE SHE then you should look in the MIKE SHE Setup dialogue to find out first what EUM data type is required and then find this type in the list MIKE SHE Editors 205 MIKE SHE Toolbox Note all fields must be filled in The last part of the dialogue is the mathematical expression you wish to evaluate Many common mathematical operations are available including LOG and LOG1O If the operation is not recognized then an error will be generated when you try to run the expression The standard order of oper ations is followed including the use of nested brackets Note all variable names are case sensitive When you are finished the Next button will take you to a summary dia logue where you can execute the function by clicking on the Execute but ton To exit the
212. er Balance oa ET extinction depth then water removed from the root zone by ET cannot be replaced by water drawn up by capillary action since the roots do not reach the top of the capillary fringe The depth of the root zone is specified in MIKE SHE s crop database and can vary in time and space The simplified ET module assumes that the unsaturated zone can consist of one or two layers The upper layer extends from the ground surface to the higher of the water table or the ET extinction depth The second layer extends from the bottom of first layer to the water table if the water table is below the ET extinction depth Thus if the water table is above the ET extinction depth the thickness of the lower layer is zero If the water table is at the ground surface then the thickness of the upper layer is also zero ET is only allowed from the upper of the two ET layers if the lower layer exists Moisture Content Ow On Hs TDi TT thickness of capillary rinse Fihiskiesa nF rnas Depth of Waler Vuble Qn x For a particular depth to wares table the soil moisture can ars bere Cin lt aNd Grew EE FP On oe oe z ae thickness of capillary tinge ET extinction depth Ihickiess al rois Figure 16 4 Allowable range for soil moisture in the upper ET layer for a given depth to water table Technical Reference for Water Movement 277 Unsaturated Flow Reference Range tor average soil moisture in upper ET
213. er Institut fiir Umweltche mie und Oko toxiko logie 57392 Schmallenberg Knudsen J 1985a WATBAL User s Guide Danish Hydraulic Institute Denmark Knudsen J 1985b WATBAL Hydrological Modelling System A Short Description Danish Hydraulic Institute Denmark Konikow L F and D B Grove 1977 Derivation of Equations describing Solute Transport in Groundwater US G S Water Resour References 377 24 25 26 1271 28 29 30 31 32 33 1341 Invest 77 19 Kristensen K J and S E Jensen 1975 A model for estimating actual evapotranspiration from potential evapotranspiration Royal Veterinary and Agricultural University Nordic Hydrology 6 pp 170 188 Leonard B P 1979 A stable and accurate convective modelling procedure based on quadratic upstream interpolation Comput Methods Appl Mech Engrg Vol 19 pp 59 98 Leonard B P 1988 Simple high accuracy resolution program for convective modelling of discontinuities Int Journal for Numerical Methods in Fluids Vol 8 pp 1291 1318 McDonald M C and A W Harbaugh 1988 A modular three dimensional finite difference groundwater flow model U S Geo logical Survey Techniques of Water Resources Investigations book 6 chap A 1 586 p Milj styrelsen 1981 The surface water component of an integrated hydrological model The Danish committee for hydrology Sus report no 12 The Danish Environmental P
214. er link The river links are shown on all the maps and the distributed data shown on the River Links map is the Topography 148 MIKE SHE Processed Data a Related Items e Rivers and Lakes V 2 p 80 e Coupling of MIKE SHE and MIKE 11 V2 p 228 3 1 4 UZ Soil Profile Grid Codes Show soil profile properties meter 6150000 Soil Profile Grid Codes 6145000 The unsaturated zone is composed of 1D soil columns If you are using the Richards equation or the Gravity flow method then these columns consist of a vertical grid with various soil properties The Show soil profile prop erties button located just above the map allows you to view a summary of the unsaturated zone grid for each cell If you click on this button the cur sor will change to a target icon When you click on a particular cell an ASCII txt file will be created and opened which contains the summary data Note that the pre processor modifies the vertical discretisation wherever the vertical cell size changes Thus if you have 10 cells of 20cm thick ness followed by 10 cells of 40cm thickness the location of the transition will be moved such that the two cells on either side will be have an equal thickness In this case cells 10 and 11 will both be 15cm Related Items e Soil Profile Definitions V 2 p 93 e Richards Equation V 2 p 262 e Gravity Flow V2 p 273 149 LEA Preprocessed Data Tab 3 1 5 UZ Class
215. eral a larger mass balance criteria should be used during model calibration to keep the initial simulation times shorter For scenario calculations the mass balance criteria can be reduced to ensure more accurate simula tions and smaller mass balance errors The SZ water balance should always be checked at the end of the simulation to ensure that the mass balance criteria used was reasonable Sink de activation in drying cells Sink de activation in drying cells Saturated thickness threshold 0 05 m Variable Units Saturated thickness threshold EUM water level Saturated thickness threshold To avoid numerical stability problems the minimum depth of water in a cell should always be greater than zero However if the water depth is close to zero then sinks in the cell such as wells should be turned off since the cell is effectively dry This value is the minimum depth of water in the cell and the depth at which the sinks are deactivated Maximum exchange from river during one time step Maximum exchange from river during one time step Max fraction of H point volume 0 9 Variable Units Maximum fraction of H point volume 42 MIKE SHE Simulation Specification LEA Max fraction of H point volume If you are simulating rivers with MIKE 11 then this represents the maximum water that can be removed from the river during one SZ time step Removing larger amounts of water coul
216. erence for Water Movement 269 LAA Unsaturated Flow Reference boundary Q 0 if the water table falls below the impermeable bed see Figure 16 1 and at same time there is an upward flux in the lower part of the profile The head boundary is re started as soon as a positive hydraulic pressure gradient is calculated or the water table starts to rise in the pro file However when the UZ model is coupled to an SZ model the UZ model exchanges water only with the top node of the SZ model This can lead to three principle conditions e Ifthe UZ model intersects the water table in the top layer of the SZ model then the lower boundary is a normal pressure boundary UZ model f Water SZ top 5 ji layer table SZ second layer e Ifthe UZ model does not extend to the bottom of the uppermost SZ layer and the water table in the SZ model falls below the bottom UZ layer then an error will be generated and the simulation will be stopped UZ model SZ top layer Water x table SZ second layer 270 MIKE SHE Richards Equation a oe e Ifthe UZ model extends below the top SZ layer and the top SZ layer dries out then the UZ model treats the bottom boundary as either a pressure boundary with the pressure equal to the elevation of the bot tom of the uppermost SZ layer or a zero flux boundary if there is an upward gradient at the lower boundary The zero flux boundary is only used for the Full Richards Equation option b
217. esults Tab Show every __ time step However if your data files are visualized too slowly then you can reduce the number of time steps being shown 164 MIKE SHE MIKE SHE EDITORS 165 166 MIKE SHE Ss 5 WELL EDITOR The Well Editor is the MIKE SHE tool for managing pumping wells The data file for the well editor is independent of the numerical model That is the well file often contains all of the wells in the entire model region including wells outside the model area The preprocessing takes care of including only the relevant wells in the numerical model The dialogue for the Well Editor is divided into e an Interactive Map V 2 p 167 of well locations e a table of Well Locations V 2 p 168 e atable of Well Filters V2 p 169 for the current well and a schematic Layers Display V 2 p 170 showing the relationship between the well screen the current geologic model and the numerical layers 5 0 1 Interactive Map meter 51 36000 Pues Taft 6134000 6132000 6130000 ve 1 28000 T7 6126000 6124000 6122000 Ter 6120000 i 580000 585000 590000 595000 o meter The interactive map displays all of the wells in the well file Clicking on individual wells will select the corresponding item in the table of well locations Similarly selecting an item from the list will change the icon of the well on the map to a red square MIKE SH
218. ethod for solving the overland flow equations is similar to the method applied to the saturated zone flow A linear matrix system of N equations with N unknown water levels is derived The matrix is then solved iteratively using the modified Gauss Seidel method Because of the non linear relationship between water levels and flows the 2 4 order term is included in the Taylor series expressing the correction of water levels as a function of the residuals The flow is calculated for the remainder of any iteration using Eq 13 13 whenever there is sufficient water in a cell that is whenever h exceeds the minimum threshold that is specified by the user The exchange between ponded water and the other hydrologic compo nents e g direct exchange with the saturated zone unsaturated infiltra tion and evaporation is added or subtracted from the amount of ponded water in the cell at the beginning of every overland flow time step Water balance correction As the flow equations so to speak are explicit during one iteration it is necessary to reduce the calculated flows in some situations to avoid inter nal water balance errors and divergence of the solution scheme Thus requiring that the water depth cannot be negative which implies that Ah gt h t rearranging Eq 13 11 gives Ax h t apem n 13 14 where ZQ is the sum of outflows and inflows Splitting 2 into inflows and outflows and remembering that outflow is negativ
219. ew you will be asked if you want to save your changes The next time you open the item in the table you will be asked if you want to overwrite the existing rev file If you click on Yes then a new rev file will be created with the default values If you click on No then your previous settings will be re loaded This is a convenient way to set up the contouring legend etc the way you want and then re use the settings The rev file can also be loaded directly in the Results Viewer by double clicking on the rev file or loading the file into the MIKE Zero project explorer 158 MIKE SHE MIKE 11 Detailed Time Series SX 4 3 MIKE 11 Detailed Time Series Refresh Obs C 8 Training Courses 2006 Beijing Demo projects Napa Napa Valley FD Mike1 1 Time Calibration Flow Huichica dfs0 item no Huichica Creek Observed YYater level m Huichica Creek H m Mar Apr May Jun Jul Aug Sep Oct Nov Dec Jan Feb Mar Apr May 02 02 02 O2 02 O02 O2 O2 O2 O2 WE 03 O03 O3 O3 ME 0 0433203 MAE 0 0898819 RMSE 0 17411 STDres 0 168634 R Correlation 0 651106 R2 Nash_Sutcliffe 0 977305 Dat number 7 x The MIKE 11 Detailed time series tab includes an HTML plot of each point selected in the Detailed MIKE 11 Output V 2 p 141 dialogue The HTML plots are updated during the simulation whenever you enter the view Alternatively you can click on the Refresh button to refresh the plot Note that the HTML plot
220. ex The coefficient C defines the interception storage capacity of the vege tation A typical value is about 0 05 mm but a more exact value may be determined through calibration The area of leaves above a unit area of the ground surface is defined by the leaf area index LAI Usually generalised time varying functions of the LAI for different crops have been established Thus in MIKE SHE the user must specify the temporal variation of the LAI for each crop type dur ing the growing seasons to be simulated Different climatic conditions from year to year may require a shift of the LAI curves in time but will generally not change the shape of the curve Typically the LAI varies between 0 and 7 The actual interception storage J is then calculated as Lace MINT paeP AD Technical Reference for Water Movement 255 LEA Evapotranspiration Reference where P is the amount of precipitation and At is the calculation time step 15 2 3 Soil Moisture The ET surface ET up 1s defined as the ground surface less the thickness of the capillary fringe If the water table is above the ET surface then ET will not reduce the moisture content of the soil since any water deficit will be replaced by water drawn up from the saturated zone via capillary action The ET extinction depth is the maximum depth to which water can be removed by transpiration It is defined as the depth of the root zone plus the thickness of the capi
221. f fluxes to the internal cells Flux boundary The total discharge of the actual time step constant or time varying is distributed over the internal cells as a function of horizontal conductivi ties cell sizes constant in MIKE SHE and full or saturated thicknesses inflow outflow respectively Inflow positive discharge Cell Factor Conductivity X Size X Full layer thickness SUMi 1 n SizeiXConiXThicki Cell Dischargei Qi Qtot X Cell Factori Outflow negative discharge Same as above but using actual saturated thickness instead of full layer thickness In the case that all cells are dry the solution will switch to full layer thickness However in this case the solution will be unstable any way Gradient boundary Each cell receives a discharge calculated from the actual gradient con stant or time varying conductivity cell size and saturated thickness Pos itive gradient yields inflow Q Gradient X Conductivity X Size X Saturated thickness Notes on Grid size Distribution of actual cell discharges to the X and Y flow velocities are stored on the MIKE SHE result file where they are needed for presenta tion and water balance extraction The X Y flow stored in a cell represents the flow from this cell to the neighbour cell in positive X Y direction The discharge of a cell in contact with more than one boundary cells of the actual boundary section is dis tributed as X Y flow components to from thes
222. f the data is stored at every time step Gridded data is not usually compared to frequent meas urements such as daily groundwater levels so the output frequency can be much less than the time step length In fact the output frequency of gridded output is often determined by visualization needs such as to make smooth animations The gridded output for the different processes can be saved at different frequencies the overland frequency is separate from unsaturated zone frequency is separated from the saturated zone frequency However you cannot save individual items at different frequencies Thus since precipi tation evapotranspiration and unsaturated flow output items are related they are all saved at the same frequency The saturated zone heads and fluxes are separated into different frequencies however because the grid ded output files for a detailed 3D model can get very large Note The Storing Time Step for SZ must be an integer multiple of the Maximum Allowed SZ Time Step that is specified in the Time Step Control dialogue In other words if the Maximum allowed SZ time step is 24 hrs then the Storing Time Step for SZ can only be a multiple of 24 hours e g 24 48 72 hours etc Similarly the storing frequency for SZ Fluxes must be an integer mul tiple of the SZ heads frequency and the storing frequency for overland flow and unsaturated flow items must be an integer multiple of their respective maximum allowed time step
223. f there are any errors then the tool will simply not run The dfs2 file must have an EUM type of Grid Codes with a unit of Inte gers See EUM Data Units VJ p 271 For Precipitation Rate V 2 p 58 data the dfsO files must be Mean Step Accumulated V1 p 247 with an EUM Type of Precipitation Rate and any valid unit such as inches hour or mm day item 204 MIKE SHE Util Se 11 2 2 t0 to dfs0 and t2 to dfs2 11 3 Util These two tools are used for converting the tO and t2 data file formats that were used in MIKE SHE up to and including the 2001 Release 11 3 1 Grid calculator The Grid Calculator tool allows you to perform complex operations on dfs2 grid files However the grid files must have the same grid dimen sions and they may not included multiple time steps or multiple items Thus this tool is much more restrictive than the grid operations available in the Grid Editor However you can make complex chains of operations and save the setup which can save you a lot of time if you are doing the same operation many times or after each simulation After the initial Tool Name dialogue is the calculation setup dialogue Calculation Setup Variable Name C Maps Topography dfs2 B C Maps Lower Level dfs2 1 2 3 bal 5 G a et el 8 Output specification Description Thickness of Layer 1 File name C Maps thickness dfs2 7 Item unit met
224. features The drainage flow simulates the relatively fast surface runoff when the spatial resolution of the individ ual grid squares is too large to represent small scale variations in the topography Drainage water can be routed to local depressions rivers or model bound aries See Groundwater Drainage V p 53 for further details about rout ing of drainage water 298 MIKE SHE 3D Finite Difference Method a oe ROUND SURFACE Zi Figure 17 4 Schematic presentation of drains in the drainage flow computations Drainage with the PCG solver When the PCG solver is used the drain flow is added directly in the matrix calculations as a head dependent boundary and solved implicitly by q h Z4 Ca 17 15 where h head in drain cell Z4 is the drainage level and C4 is the drain conductance or time constant Exchange with surface water The recharge discharge to the surface water is depended on the compo nents included in the simulation The saturated zone component calculate the surface recharge discharge in point with no unsaturated zone that is if the unsaturated zone component is excluded or the piezometric head is above surface level The exchange between SZ and OL is carried out implicitly by constantly updating the overland water depth and is calculated by use of the Darcy equation Q AhC Technical Reference for Water Movement 299 a oe Saturated Flow Reference where C 7 7
225. file or e as a uniform soil If either the Richards Equation method or the Gravity Flow are used then the data tree can include the following items e Soil Profile Definitions e Groundwater Depths used for UZ Classification e Partial automatic classification and e Specified classification Whereas if the Two Layer Water Balance is used then the data tree will include 90 MIKE SHE Unsaturated Zone e 2 Layer UZ soil properties and e ET Surface Depth Column Classification If the either Richards Equation or the Gravity Flow Module are chosen for calculating the unsaturated zone flow then the top level Unsaturated Zone dialogue contains a section for the column classification However if the Two Layer Water Balance is chosen then the Column Classification sec tion is hidden Since UZ computations in all grid squares for most large scale applica tions requires excessive computation time MIKE SHE enables you to compute the UZ flow in a reduced subset of grid squares The subset clas sification is done automatically by the pre processing program according to soil types vegetation types climatic zones and depth to the groundwa ter table e Automatic classification The automatic classification requires a dis tribution of groundwater elevations see Groundwater Depths used for UZ Classification This can be either the initial depth to the ground water based on the initial heads or you can supply a dfs2 map of
226. flow occurs when the soil is completely saturated In this case the infiltration from OL goes directly to the SZ and the mass flux is equal to the infiltration multi plied with the concentration on the overland e Exchanges with MIKE 11 are also treated explicitly as exchange flows Inflow and outflow respectively are multiplied by the concentration in the river or the adjacent grids to the groundwater e SZ Drainage to the overland or MIKE 11 or the boundary is also treated as an SZ sink and the mass receiving component and is again calculated by multiplying the exchange flux with the concentration 19 2 5 Transport in Fractured Media MIKE SHE AD is able to simulate solute transport in fractured media under some simplifying conditions If we assume that water flows only in the fractures and that solutes can enter into the soil matrix as immobile solutes the advection dispersion equation changes to Gin at at 19 15 O Gu Cm amp envw es Re Ox O x where c is the concentration of the solute subscripts m and im are for mobile and immobile respectively R is the sources or sinks Dj is the dispersion tensor and v is the velocity tensor determined from fracture porosity Technical Reference for Water Quality 339 Advection Dispersion Reference The exchange of mass between the mobile water phase in the fractures and immobile water phase is described by the traditional diffusion equation
227. for any com mand area and each Priority usually only 1 do the following 1 Calculate the total demand of remote and shallow well sources of the actual Rank and Priority from all baseflow reservoirs 1 amp 2 2 Calculate a supply factor for each baseflow reservoir 1 amp 2 If the demand is less than the storage of the actual reservoir the supply factor is 1 0 Otherwise calculate a value between 0 and 1 available storage demand 69 LEA Setup Data Tab 3 Calculate the final irrigation from each source of the actual Rank and Priority calculated demand from actual baseflow reservoir 1 and or 2 X corresponding supply factor 4 Subtract the final irrigation volumes from the available volume of each baseflow reservoir 1 amp 2 and go to next rank and priority In the next SZ Linear Reservoir time step the calculated irrigation vol umes are subtracted from the baseflow reservoir storages and depths and the irrigation pumping is stored together with the other SZLR results for water balance calculation etc The available volume of water in each baseflow reservoir is calculated as Jusi Fraction ept Available reservoir eee ora Percolation Volume depth yield area to water Reservoir rem Fraction ept Available _ reservoir ae ae i Percolation Volume depth yield area to water Reservoir Water Source Types The Sources table specifies the different sources available for irrigation
228. ge J A 1982 Engineering Applications of Computational Hydraulics Vol I Pitman Advanced Publ Program London Ammentorp H C A Refsgaard 1991 Operationalizing a three dimensional solute transport model in Danish Report M4 7 Landfill project Danish Environmental Protection Agency Bear J 1979 Hydraulics of groundwater McGraw Hill Inc 567 pp Boesten J J T I amp van der Linden A M A 1991 Modelling the influ ence of sorption and transformation on pesticide leaching and persist ence J Environ Qual 20 425 435 Brusseau M L 1995 The effect of nonlinear sorption on the trans formation of contaminants during transport in porous media Journal of Contaminant Hydrology 17 p 277 291 Bear J and A Verruijt 1987 Modeling Groundwater Flow and Transport D Reidel Pub Com Dordrecht Holland Burnett R D and E O Frind 1987 Simulation of contaminant transport in three dimensions 2 Dimensionality Effects Water Resour Res 23 4 695 705 Chow T C Maidment D R and Mays L W 1988 Applied Hydrology McGraw Hill Series in Water Resources and Environ mental Engineering pp 201 210 257 263 Crawford N H and Linsley R K 1966 Digital simulation in hydrology the Stanford Watershed Simulation Model IV Technical Report no 39 Department of Civil Engineering Stanford Univer sity Stanford CA 210p Ekebj rg L and Justesen P 1991 An explicit scheme for advec tion d
229. gradient input cell has zero thickness has a horizontal hydraulic conductivity of zero is an inactive internal boundary cell or is a fixed head internal boundary cell A warning will be issued if the flux gradient boundary is a head controlled flux GHB internal boundary cell or is a fixed head drain internal boundary cell Related Items Saturated Flow Reference V 2 p 289 Boundary Conditions V 2 p 296 120 MIKE SHE Saturated Zone 2 16 20 Internal boundary conditions Boundary Name Grid Code Value Boundary Type Data Type Grid code 1 Head Contralled Flux GHI Time varying dfsO Controlling head Time Series File Create Leakage Controlled by C 5 Testing NASaby 1 46 678 fyn dfs0 i i Edit Total conductance w ltemmname Elevation meter Internal Boundary Conditions 6140000 Internal Boundary Conditions dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The map dialogue for the internal boundary conditions allows you to spec ify the locations of the various boundary conditions Any Integer Code value is permissible and a separate item will be added to the data tree below this level with one item for each unique integer code in the domain Only one integer code is allowed per cell which means that no cell can have more than one boundary condition If you use a polygon shp file you can create and edit the polygons
230. gular Interpolation VJ p 264 2 9 Precipitation r Snowmelt I Include snowmelt Precipitation is always included in the data tree but there is only one option That is to include or not include Snowmelt Snowmelt If Snowmelt is included then Evapotranspiration must also be included If Snowmelt is included then two additional dialogues are added to the data tree one for the Snowmelt Constants and the other for the distributed Air Temperature In MIKE SHE Snowmelt is calculated on the basis of the degree day using a simple method that only requires the air temperature a degree day factor mm snow day degree C and a threshold temperature defined the temper ature at which melting occurs usually 0 C Related Items e Time Series Data V 1 p 243 e Snowmelt Constants V 2 p 62 e Air Temperature V 2 p 60 57 LEA Setup Data Tab 2 9 1 Precipitation Rate Precipitation Rate dialogue Type Time varying Real Data EUM Data Grid Code Units Time Series Precipitation Rate e g mm hr or EUM Data Rainfall e g mm Units The precipitation rate is the measured rainfall and snowfall You can specify the precipitation rate as a rate for example in mm hr or as an amount for example in mm If you use the amount method MIKE SHE will automatically convert this to a rate during the simulation If you use a rate then the EUM Data Units must be Precipitation and the time series must be Mean St
231. h sub dialogue data EUM Data Units Grid Code 87 Setup Data Tab The Overland flow zones are used to defined the topographic zones for the simple catchment based overland flow solution The overland flow zones are typically defined as areas with similar topography For example the river flood plain would be a typical topographic zone although it might be included in many subcatchments Each unique grid code in the Overland Flow Zones map will generate a sub item in the data tree where the following parameters must be speci fied Slope The Slope variable is a representative slope in the topographic area It can be thought of as the average slope but it is really a calibra tion parameter as it can t really be calibrated to a true average Slope Length Like the Slope itself the Slope Length is a representative distance that water must travel as overland flow before reaching a ditch or stream It can be thought of as the average travel distance but like the Slope it is really a calibration parameter as it can t really be cali brated to a true average Manning Number The Manning M is equivalent to the Stickler rough ness coefficient the use of which is described in the Overland Flow Reference chapter The Manning M is the inverse of the more conven tional Mannings n The value of n is typically in the range of 0 01 smooth channels to 0 10 thickly vegetated channels This corre sponds to values of M betwee
232. he Saturated Zone V 2 p 329 104 MIKE SHE Saturated Zone 2 16 1 Interflow Reservoirs Name Global Specific Yield Interflow Percolation 0 Time Constant Time Constant Initial Depth fo id jo Id 0 m Threshold Depth Bottom Depth 0 m bo m The interflow reservoirs are used to route near surface groundwater to local streams In the Linear Reservoir Method each reservoir is assumed to be like a bathtub with an inflow from infiltration and the upstream res ervoir as well as an outflow flowing into the next downstream reservoir and down into the baseflow reservoir beneath Each linear reservoir flows only into the next downstream interflow reservoir or into a stream if it is the lowest reservoir Note Polygon shape files are currently not allowed for defining interflow reservoirs The flow reference between interflow reservoirs depends precisely on the integer code numbers assigned to the reservoirs Within a subcatchment the interflow reservoir with the higher number always flows into the reservoir with the next lowest number Each Interflow reservoir requires a value for Specific Yield to account for the fact that the reservoir contains a porous media and is not an actual bathtub Initial depth the initial depth of water in the reservoir measured from the ground surface Bottom depth the depth below the ground surface of the bottom of the reservoir If the water level drops to the bo
233. he infiltration from upper layers by reduc ing the available gradient Without the Canyon option MIKE SHE effectively assumes that the river is hydraulically connected to the upper most model layer since MIKE SHE calculates the exchange flow with all layers that intersect the river based on the difference between the river level and the water table 238 MIKE SHE Area Inundation using Flood Codes areal source sink LAA Currently this option is only available for steady state models It is acti vated by means of the boolean Extra Parameter Enable Canyon Exchange For more information on the use of extra parameters see Extra Parameters V 1 p 145 14 3 Area Inundation using Flood Codes areal source sink The MIKE SHE MIKE 11 coupling allows you to simulate large water bodies such as lakes and reservoirs as well as flooded areas If this option is used MIKE SHE MIKE 11 applies a simple flood mapping procedure where MIKE SHE grid points e g grid points in a lake or on a flood plain are linked to the nearest H point in MIKE 11 where the water lev els are calculated Surface water stages are then calculated in MIKE SHE by comparing the water levels in the H points with the surface topo graphic elevations 14 3 1 Determination of the Flooded Area and Water Levels The flooded area in MIKE SHE must be delineated by means of integer flood codes where each coupling reach is assigned a flood code During the simul
234. he potential evapotranspiration demand is still not satisfied water is extracted from the saturated zone The amount that can be extracted is expressed as a function of the depth to the ground water table as described by the MODFLOW ET package The actual evapotranspiration is calculated as the sum of the above 4 proc esses ET from the Canopy Evapotranspiration is deducted from the canopy storage assuming poten tial evapotranspiration rate The actual evapotranspiration from canopy Ean iS given as minimum of potential evapotranspiration rate multiplied with the time step and actual interception storage Ecan min INT Ep At mm INT is subsequently updated by deducting Esan INT INT Ecan mm ET from Ponded Water If the interception water storage cannot satisfy potential evapotranspira tion rate water is to the extent possible removed from the ponded water storage dpc E pon MIn doc Ep Ecan At mm and d is updated doc doc Epon mm Technical Reference for Water Movement 259 LEA Evapotranspiration Reference ET from the Unsaturated Zone If the potential evapotranspiration demand is still not satisfied water is extracted from the unsaturated zone if available E E min V uz dt Ep Ea Where V is the available water in the unsaturated zone given as Vaz act Omin Za Za ET from the Saturated Zone If the potential evapotranspiration demand is still
235. he volumetric flow in vertical direction g is the volu metric flow in horizontal directions R is the volumetric flow rate per unit volume from any sources and sinks Ax is the spatial resolution in the hor Technical Reference for Water Movement 301 Saturated Flow Reference izontal direction and H is either the saturated depth for unconfined layers or the layer thickness for confined layers See Figure 17 5 and Figure 17 6 for a description of the geometric relationships between the cells The horizontal flow components in Eq 17 20 are given by git CAh 17 21 where C is the horizontal conductance between any of the adjacent nodes in the horizontal directions The horizontal conductance in Eq 17 21 is derived from the harmonic mean of the horizontal conductivity and the geometric mean of the layer thickness Thus the horizontal conductance between node i and node i will be KH i e KH g Azi ijet A 6 k KA j 17 22 KH i l j where KH is the horizontal hydraulic conductivity of the cell and 4z is the saturated layer thickness of the cell The vertical flow components in Eq 17 20 are given by K Ax2Ah 17 2 AZ j k Az 3 git zZ ij k 1 where K is the average vertical hydraulic conductivity between nodes in the vertical direction and Az j and Az 4 are the saturated thicknesses of layers k and k respectively For the average vertical hydraulic con d
236. hes then you can chose User Specified and specify the river net work file Related Items e Rivers and Lakes V 2 p 80 MIKE SHE Well Database Overlays IV Display Well parameter file Use well parameter file specified in Pumping and observation wells dialog WEL C User specified vs S If you want to display a MIKE SHE Well database in your map views then you can add a Well Overlay By default the well database defined in the Pumping Wells dialogue is displayed If you would rather display a different well database for example an overview database with fewer wells then you can chose User Specified and specify the well database file Show well names This checkbox turns the well names on and off in the map view Related Items e Pumping Wells V 2 p 129 25 oa Setup Data Tab 2 1 7 Current Layer The Current Layer item refers to the grid item currently being displayed in the current map view Transparency This is used to control the way pixel colours are averaged for displaying images that overlay one another 2 2 Simulation Specification The Simulation Specification dialogue is the key dialogue in the program In this dialogue you can select the key options for each of the components included in the simulation including e Overland Flow see also Overland Flow Reference V 2 p 211 26 MIKE SHE Simulation Specification LEA the Finite Difference Meth
237. hnical Reference for Water Movement 283 Unsaturated Flow Reference correction procedure corrects the water table of the upper SZ cell i e the lower boundary condition for the UZ The correction procedure of step wise water table adjustments and addi tional UZ calculations is repeated until Egy is less than Emax for each column that has failed the Emax criteria During this correction procedure the UZ module of MIKE SHE operates on a copy of the water table solu tion for the upper SZ calculation layer After each SZ time step the UZ copy is updated with the new water table from the SZ solution and then adjusted during the succeeding UZ time step s until the next SZ time step The calculated adjustments are converted to an additional flux term mul tiplied with the specific yield of SZ and divided by the SZ time step length and added to the uncorrected UZ to SZ flux term The corrected UZ to SZ flux term is used by the SZ module as an explicit source sink term during the next SZ time step The size of Emax determines the largest allowable mass balance before adjustments are made Typically an Emax value between 1 2 mm is an appropriate choice for regional MIKE SHE simulations The Emax value is specified in the UZ Computational Control Parameters V 2 p 39 dia logue 16 6 1 Steps in the Coupling Procedure The following outlines the actual steps in the coupling procedure used for each UZ time step 1 If the total w
238. hosen ranging from 10 cm to 30 cm 16 2 Gravity Flow The driving force for transport of water in the unsaturated zone is the gra dient of the hydraulic head h which includes a gravitational component z and a pressure component y Thus h z w 16 24 The gravitational head at a point is the elevation of the point above the datum z is positive upwards The reference level for the pressure head component is the atmospheric pressure Under unsaturated conditions the pressure head y is negative due to capillary forces and short range Technical Reference for Water Movement 273 Unsaturated Flow Reference adsorptive forces between the water molecules and the soil matrix How ever in the gravity flow module the pressure head term is ignored and the driving force is due entirely to gravity Thus for vertical flow the vertical gradient of the hydraulic head becomes A cc 1 16 25 The volumetric flux is then obtained from Darcy s law mn K 0 K 0 16 26 where K 8 is the unsaturated hydraulic conductivity Assuming that the soil matrix is incompressible and the soil water has a constant density the continuity equation will be 00 _ _0q_ Se 16 27 where S is the root extraction sink term 16 2 1 Solution method In the Gravity Flow Module Equation 16 27 is solved explicitly from the top of the soil column downward At the top of the soil column the infiltration rate is first set equal to the
239. hree types of boundary conditions 1 Dirichlet conditions Type 1 where the hydraulic head is prescribed on the boundary 2 Neumann conditions Type 2 where the gradient of the hydraulic head flux across the boundary is prescribed 3 Fourier conditions Type 3 where the head dependent flux is pre scribed on the boundary The head can be prescribed for all grid nodes i e at the catchment bound ary as well as inside the model area and for all computational layers The head may be time invariant equal to the initial head or can vary in time as specified by the user An important option is the transfer of space and time interpolated head boundaries from a larger model to a sub area model with a finer discretisation Prescribed gradients and fluxes can be specified in all layers at the model boundary Sinks and sources in terms of pumping or injection rates can be specified in all internal nodes If the unsaturated zone component is not included in the model the ground water recharge can be specified The exchange flow to the river system is included in the source sink terms and can be regarded as a Type 3 boundary condition for cells with contact to the river system The exchange flow is a function of the water level in the river the river width the elevation of the riverbed as well as the hydraulic properties at the riverbed and aquifer material 296 MIKE SHE 3D Finite Difference Method a oe Distribution o
240. hydraulic conductivity in the upper SZ calculation layer is much greater than the saturated hydraulic conductivity used in the UZ or if e the drainage time constant is too high In the first two cases above the epsilon term can exceed E because the UZ module cannot get rid of epsilon because there is no available storage for the error term In the third case the UZ and SZ hydraulic properties should be consistent or it will be difficult for MIKE SHE to simulate con Technical Reference for Water Movement 287 LAA Unsaturated Flow Reference sistent vertical flow rates In the last case the drainage time constant should be reduced to prevent excessive and unrealistic drainage outflows from the SZ module 288 MIKE SHE 3D Finite Difference Method a oe 17 SATURATED FLOW REFERENCE The Saturated Zone SZ component of MIKE SHE WM calculates the saturated subsurface flow in the catchment MIKE SHE allows for a fully three dimensional flow in a heterogeneous aquifer with shifting condi tions between unconfined and confined conditions The spatial and temporal variations of the dependent variable the hydrau lic head is described mathematically by the 3 dimensional Darcy equa tion and solved numerically by an iterative implicit finite difference technique MIKE SHE gives the opportunity to chose between two groundwater solv ers the SOR groundwater solver based on a successive over relaxation solutio
241. icense period length is defined by the time steps in the specified dfs0 file During the simulation the license data is included in the calculation of the available water volume of each source The module keeps track of the actual available license volume Whenever this is reached or exceeded the source will be closed until a new license period starts or the end of the simulation When a source is closed for this reason a message is printed in the wm_print log file Notes e The dfs0 file EUM Data Units V 1 p 271 must be Water volume m or other volume unit and the time series type must be Step Accumu lated VI p 247 e The specified volumes cover the period from the previous value or start of simulation until the date of the actual value e The files may contain delete values These are simply ignored This makes it possible to include licenses for several sources in one file even when the dates of the different source licenses differ e A new irrigation log file has been included in the results output projectname_IrrigationLicenseLog dfs0 e This log file contains the actual available license volume of each source with license included stored as instantaneous values at the end of every time step This makes it easy to identify the periods where sources have been closed due to license shortage e Note Unused license volumes are NOT carried over to the next license period use it or loose it 7
242. ies output 4 4 2 Statistic Calculations The standard calibration statistics calculated based on the differences between the measured observations and the calculated values at the same location and time Thus the error or residual for an observation calcula tion pair is Ei Obs Calc 4 1 where E is the difference between the observed and calculated values at location i and time t Mean ME The mean error at location i where n observations exist is gt Obs Calc ME E ____ 4 2 n Mean Absolute Error MAE The mean absolute error at location i where n observations exist is gt Obs Calc MAbs ES 4 3 161 Results Tab Root Mean Square Error RMSE The root mean square error at location i where n observations exist is Z 065 0 Calc r Ii o o 4 4 RMSE n Standard Deviation of the Residuals STDres The standard deviation of the residuals at location i where n observations exist is ET S Obs Calc E STD ro rq ae 4 5 n Correlation Coefficient R The correlation coefficient at location i is 5 Calc Obs S Obs Obs 1 t where Obs i is the mean of the observations at location i Nash Sutcliffe Correlation Coefficient R2 The Nash Sutcliffe coefficient at location i where n observations exist is 5 Obs Calc 2 M 4 7 t where Obs is the mean of the observations at loc
243. iffusion modelling in two dimensions Computer Methods in 376 MIKE 21 Se 12 13 14 15 16 17 18 19 20 21 22 23 Applied Mechanics and Engineering 88 3 287 297 FAO 1979 Yield response to water FAO irrigation and drainage paper no 33 FAO Rome Italy Fetter C W 1992 Contaminant Hydrogeology Macmillan Pub Com New York New York Fleming G 1975 Computer Simulation Techniques in Hydrology Elsevier Environmental Science Series Freeze R A Cherry J A 1979 Groundwater Prentice Hall Inc Englewood Cliffs N J Hill M C 1990 Pre conditioned conjugate gradient 2 PCG2 a computer program for solving groundwater flow equations U S Geological Survey Water Resources Investigations Report 90 4048 43 p Jarvis N 1991 MACRO A model of water movement and solute transport in macroporous soil Monograph Reports and disserta tions 9 Dept of Soil Science Swedish Univ of Agrig Sci Upp sala Sweden Jensen K H 1983 Simulation of water flow in the unsaturated zone including the root zone Institute of Hydrodynamics and hydraulic engineering Technical University of Denmark Series Paper no 33 259pp Jensen K H H C Ammentorp and T Sevel 1984 Modelling sol ute transport in the unsaturated zone Nordic Hydrology 15 4 5 223 234 Klein M 1995 PELMO Pesticide Leaching Model version 2 01 Users Manual Frauenhof
244. ification Grid Codes meter Classification grid codes 6150000 F7 eae eae qosteadbhssdacantes Psesana ak drnncinns 6145000 aoe a 2 eS ee eee 6140000 aa A aces OB A pe 3 E 6135000 6130000 6125000 f P T 6120000 _ 6115000 4 srepet airs Ae ga ee 6110000 6105000 oe ee ae rE 6100000 570000 580000 590000 600000 meter If certain conditions are met then the flow results for a 1D unsaturated zone column can be applied to columns with similar properties In this map each numbered item is a calculation point The cell with a calcula tion point is given an integer grid code with a negative value The flows calculated during the simulation in the cells with the negative code will be transferred to all the cells with the same positive grid code value For example if an UZ recharge to SZ of 0 5 m3 day is calculated for UZ grid 150 MIKE SHE Processed Data a code 51 then all the SZ cells below the UZ cells with a grid code of 51 will also be given the same recharge By just looking at the map it can be difficult to distinguish which calcula tions are being transferred to which cells An easier way to look at this is to save the map to a dfs2 file right click and then open the file in the Grid Editor where it is much easier to search for cell numbers Related Items e Soil Profile Definitions V 2 p 93 e
245. ified either by a constant level or by a distrib uted file The number of numerical layers will be identical with the number of geologic layers Explicit definition of lower levels If you define the vertical discretisa tion explicitly each computational layer is defined by its lower eleva tion Minimum layer thickness The minimum thickness of the calculation layers must be specified to adjust the geological model or the specified levels to prevent layers with zero thickness 2 16 17 Lower Level Numerical Layer Lower Level dialogue Type Stationary Real Data EUM Data Units Elevation The Lower Level value is used to define the bottom of the numerical lay ers if they are being explicitly defined The bottom of the numerical lay ers is always equal to the top of the layer underneath 2 16 18 Initial Potential Head Initial Potential Head dialogue Type Stationary Real Data EUM Data Units Elevation The Initial Potential Head is the starting head for transient simulations and the initial guess for steady state simulations The choice of initial head for 117 a Setup Data Tab steady state simulations may affect the rate of numerical convergence depending on the solver used 2 16 19 Outer boundary conditions Boundary segments specified clockwise a Lom Head Zero Flux mete Outer Boundary Conditions 590000 580000 Boundary type GB Gradient LJ
246. il moisture in upper ET layer ies ne ee OA PE OE G0 arte act OLEA P LO ae fis lt Waler buble Maximum depth for transpiration Root Depth ET Lower TET layer only exists when water table is below this level Awerape soil moisture in lower ET layer Figure 15 10 Soil moisture ranges for different depths to water table If the water table is at the ground surface then the moisture content equals the saturated moisture content 0 and all ET is taken from the saturated zone If the water table is below the ground surface but above the ET surface then the average moisture content of the ET layer is a linear function of the depth of the water table That is the average moisture content in the ET layer is lower when the water table is lower If the water table is above the ET surface the capillary fringe reaches the ground surface Thus the water content is not dependent on ET and any water lost to ET will be replaced from the groundwater table through capillary action If the water table is below the ET surface but above the ET extinction depth then the average water content will vary between a minimum Oin and a maximum Omax Omax 18 the water content that would be present if no ET occurred 0 is the minimum water content that can exist in the upper ET layer when ET is active Both Onin and Omax vary linearly with the depth to the water table That is Onin and Onax are lower when the water table is lower
247. in the Simple Shape Editor V 2 p 201 Each unique polygon will have a sepa rate entry in the data tree Available boundary conditions The following boundary conditions can be defined for each integer code Fixed Head For a fixed head boundary you specify the head in the cell The model will not calculate the head in the cell Care should be taken when specifying fixed head boundary conditions as the cell becomes an infinite source or sink of water The fixed head can be a prescribed value fixed at the initial value from the initial conditions assigned to a dfsO time series file or assigned to a time varying dfs2 file The last 121 Setup Data Tab option is typically from a results file It could be from a regional results file which can be extracted using the MIKE Zero Toolbox Extraction tool 2D Grid from 3D files Or it could be from a previous run of the same model Fixed Head Drain For a fixed head drain boundary you specify a refer ence head If the cell water level is above the reference level then the boundary acts like a normal fixed head boundary conditions If the head in the cell falls below the reference level then the boundary con dition is turned off That is if the simulated head drops below the head reference level the flux is set to zero Thus the fixed head drain allows only water extraction The reference head can be a prescribed value fixed at the initial value from the initial conditions a
248. ing the slope of the drains calculated from the drainage levels in each cell Thus as long as a downward slope is found the drain flow will continue until crossing a river or the model boundary If local depressions in the drainage levels exist the SZ nodes in these depressions may become the recipients for a number of drain flow pro ducing nodes This often results in the creation of a lake at such local depressions This option is not allowed if using Time varying drainage parameters V 1 p 154 Drainage routing based on grid codes This method is often used when the topography is very flat which can result in artificial depressions or when the drainage system is very well defined such as in agricultural applications 124 MIKE SHE Saturated Zone a In this method the drainage levels and the time constants are defined as in the previous method However a grid code map is also required which is used to link the drain flow producing cells to a recipient node The drain levels are still used to calculate the amount of drain flow pro duced in each node but the routing is based only on the code values in the drain code file Distributed drainage options Choosing this method adds the Option Distribution item to the data tree With the Option Distribution you can specify an integer grid code distribution that can be used to specify different drainage options in different areas of your model Ifthe grid code equals
249. ins in MIKE SHE which are described in more detail in the section Drainage Hydrogeologic parameter definition The first option allows you to specify the hydrologic parameters of the geologic layers and lenses directly by means of dfs2 grid files point line theme shp files or irregular xyz point values The second option allows you to assign the hydrologic parameters to the geologic layers by means of zones with uniform properties whereby the zones are defined by integer grid codes Dispersion If your simulation includes water quality modelling in the saturated zone then you must also define the type of dispersion you want to simulate Dispersion is the physical process that causes solutes to spread longitudi nally vertically and horizontally as they move through the soil The dis persion essentially represents the natural microscopic variations in pore geometry that cause small scale variations in flow velocity No dispersion Dispersion is ignored and no dispersivities need to be specified Isotropic The transverse horizontal and transverse vertical dispersivities are assumed to be the same Only two dispersivities need to be speci fied the longitudinal and the transverse dispersivities Anisotropic The horizontal and vertical transverse dispersivities are dif ferent which requires the specification of five different dispersivities Related Items e Saturated Flow Reference V 2 p 289 e Solute Transport in t
250. int type Circle v i Text Annotation Color as point Background Transparent Individual color a Parameters for Lines and Folpaor e color 7 ir tule T Text Annot Color as jine polygon Backaoround l e ndividual cole x r Units Units of X and Y axises meter 7 If you want to add an ESRI shape shp file to the map view then you must select a Shape overlay Shape File and Item In the file browser dialogue you can select from the available items in the shp file Parameters for Points This section allows you to customize the way point shp themes are displayed Parameters for Lines and Polygons This section allows you to custom ize the way line and polygon themes are displayed Units The ESRI shp format does not include information on whether the length units are SI or Imperial So this combobox allows you to select the length units from a range of SI and Imperial length units 24 MIKE SHE Display 2 1 5 2 1 6 River Overlays V Display MIKE 11 network fle Use network file specified in Rivers and Lakes dialog NWK11 C User specified l If you want to display a MIKE 11 River network in your map views then you can add a River Overlay By default the river network defined in the Rivers and Lakes dialogue is displayed If you would rather display a dif ferent river network for example an overview network with fewer branc
251. ion AD simula tions The connections are not important to the calculation of the exchange flows between the hydrologic components e g overland to river or SZ to river 230 MIKE SHE Coupling of MIKE SHE and MIKE 11 LEA In the example shown in Figure 14 1 the river links of the tributary are correctly connected to the main branch This will happen automatically when e the hydraulic connection is defined in the MIKE 11 network AND e the connection point the chainage on the main branch is included in a coupling reach AND e the connection point the chainage on the tributary is included in a coupling reach If the connection does not satisfy the above criteria then there may be a gap in the MIKE SHE branch network and the limitations outlined in the previous section will apply 14 1 2 The River Link Cross section The MIKE 11 HD hydraulic model uses the precise cross sections as defined in the MIKE 11 xns11 cross section file for calculating the river water levels and the river volumes However the exchange of water between MIKE 11 and MIKE SHE is calculated based the river link cross section The river link uses is a simplified triangular cross section interpolated distance weighted from the two nearest MIKE 11 cross sections The top width is equal to the distance between the cross section s left and right bank markers The elevation of the bottom of the triangle equals the low est depth of the MIKE
252. ion in the current time step and what does not infil trate will flow as overland flow to the adjacent cells Check water level before routing to river If this option is checked in the Land Use dialogue then MIKE SHE checks to make sure that the water level in the receiving river is lower than the drain level in the current cell If the river is higher than the drain level then no paved runoff will occur 68 MIKE SHE Land Use 2 10 3 Irrigation Command Areas irrigation command area ID Global Sources Water Application 1 River Sprinkler 2 Single well Drip Shallow well Sheet h External Sprinkler Shallow well source Irrigation Command Areas Conditions Irrigation selected in Land Use and UZ and ET simu lated dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The Irrigation Command Areas are used to describe where the water comes from and how the irrigation water is applied to the model The Irrigation Command Area data item is divided into two dialogues The first is the distribution dialogue for the Command Areas and the sec ond is the Water source and Application method for each of the command areas Each source can also be limited by a licensed maximum amount of water in any period License Limited Irrigation V2 p 75 Calculation sequence and shortage handling for SZ Linear Reservoirs For each rank no of ranks max no of sources specified
253. ion of that species 2 5 Species Parameters Teee Temp decay Water content Plant uptake Temperature exponent decay transpiration factor 20 0 1 0 0 1 34 Nacl Species Parameters Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue Reference Temperature The reference temperature is used for the tem perature dependent decay rate calculations Temp decay exponent This is the exponent used in the temperature dependent decay rate calculations Water content decay exponent This is the exponent used in the water content decay rate calculations for the unsaturated zone Plant uptake transpiration factor This is the factor that determines the rate at which plants will remove the mobile solute from the water Solubility Since evaporation can cause the overland concentration to increase solubility needs to be specified to avoid unrealistic high con 51 Setup Data Tab 2 6 centrations The species precipitates if the concentration exceeds the solubility The precipitate dissolves again if the concentration falls below the solubility The solubility is a uniform value per species with units of g m2 Model Domain and Grid 10 45 Testing NRSaby MAPS nneat3c dF Edit Catchment defined by Shape File si gt a Edt Create vo C Catchment defined by Dfs File C 5 Testing NRSaby GIS model_area s P it
254. ion of the topography in the flood code cells This file is only used if the Bed Topography Option is set in MIKE 11 Related Items e Area Inundation using Flood Codes areal source sink V 2 p 239 e Inundation options by Flood Code V 1 p 173 2 13 Overland Flow The main dialogue for overland flow includes several options when the Finite difference method is selected It does not contain any options when the Sub catchment based method is selected Separated overland flow areas Overland groundwater Exchange Full Contact in entire catchment Reduced contact in subareas If the Finite Difference method is selected in the Simulation Specification dialogue the basic items required for the calculation of Overland Flow are e the Manning number which is equivalent to the Stickler roughness coefficient e the Detention Storage and 82 MIKE SHE Overland Flow Se e the Initial Water Depth on the ground surface ponded water There are two options available in the Overland Flow dialogue Separated overland flow areas The first allows you to divide the model area into overland flow zones which are conceptually areas separated by dikes or embankments With this option overland flow will not be allowed to flow between zones If this is checked then an additional item Separated Flow Areas V 2 p 87 will be added to the data tree Overland groundwater exchange If the soil profile becomes completely saturate
255. iply both sides of the equations by h the relationship between the velocities and the depths may be written as 1 2 uh K 82 s Ox 1 2 vh K 22 7 997 oy 13 8a 13 8b Note that the quantities uh and vh represent discharge per unit length along the cell boundary in the x and y directions respectively Also note that the Stickler roughness coefficient is equivalent to the Manning M The Manning M is the inverse of the commonly used Man nings n The value of n is typically in the range of 0 01 smooth channels to 0 10 thickly vegetated channels which correspond to values of M between 100 and 10 respectively Technical Reference for Water Movement 213 a Overland Flow Reference 13 1 2 Finite Difference Formulation Consider the overland flow in a small region see Figure 13 1 of a MIKE SHE model having sides of length Ax and Ay and a water depth of h t at time f Qn Ay Qw gt lt Qe Figure 13 1 Square Grid System in a small Region of a MIKE SHE model A finite difference form of the velocity terms in Eq 13 1 may be derived from the approximations E uh H UM casr UM vest 13 9 and i Wt 13 10 y Ay north south where the subscripts denote the evaluation of the quantity on the appropri ate side of the square and noting that for example Ax uh 5 is the vol ume flow across the western boundary Ah h t An h 1 1 224
256. is one hour a high intensity one hour event could lead to time steps of a few minutes during that one hour event Max infiltration amount per time step If the total amount of infiltration due to ponded water mm in the current time step exceeds this amount the time step will be reduced by the increment rate Then the infiltration will be recalculated If the infiltration criteria is still not met the infiltration will be recalculated with progressively smaller time steps until the infiltration criteria is satisfied Input precipitation rate requiring its own time step If the amount of precipitation mm divided by the time step length hr in the current time step exceeds this amount the time step will be reduced by the increment rate until this criteria is met That is the precipitation time series will be re sampled with progressively smaller time steps until the precipitation rate criteria is satisfied Multiple sampling is impor tant in the case where the precipitation time series is more detailed than the time step length However the criteria can lead to very short time steps during short term high intensity events For example if your model is running with maximum time steps of say 6 hours but your 32 MIKE SHE Simulation Specification LEA precipitation time series is one hour a high intensity one hour event could lead to time steps of a few minutes during that one hour event Actual time step for the different comp
257. is regenerated every time you enter the view So if you have a lot of plots and a long simulation then the regeneration can take a long time Related Items e Detailed MIKE 11 Output V 2 p 141 e Statistic Calculations V 2 p 161 159 a oe Results Tab 4 4 Run Statistics Run statistics can be generated in HTML format for a MIKE SHE simula tion The run statistics table information can be copied and pasted directly into any word processing program such as Microsoft Word or spread sheet such as Microsoft Excel The Run Statistics HTML document includes MIKE SHE and MIKE 11 results for all items included in the MIKE SHE and MIKE 11 detailed time series sections that also include observation data To calculate Run Statistics for a simulation navigate to the Results Tab and the Run Statistics item on the menu tree Press the Generate Statistics button on the Run Statistics window to perform the statistical calculations For some simulations with long simulation periods and or a lot of calibra tion data it can take several minutes to generate the run statistics since the entire dfsO file is loaded into memory After successful completion of the Generate Statistics phase the Run Sta tistics HTML document will be displayed in the window on the Run Sta tistics page see below Start Date End Date D Refresh 2002703701 02 00 x 2003 06 02 0200 f7 R Name Data type Correlation Y
258. iteration stop crite ria are reached or when the maximum number of iterations is reached The iteration stop criteria consist of a mass balance criteria and a head criteria Both of these criteria must be chosen carefully to ensure that the solution has converged to the correct solution The default option settings normally perform well in most applications Usually there is no need for changes Changes to the default options should not be done unless the solution does not converge or convergence is extremely slow Maximum number of iterations The maximum number of iterations should be sufficiently large to avoid water balance errors due to non convergence Maximum head change per iteration The head criteria determines the accuracy of the solution The computational time is very dependent on the value used A value of 0 01m 0 025ft is usually sufficient During the initial model calibration a higher stop criteria can be used The sen sitivity of the head stop criteria should always be examined 41 a a Setup Data Tab Maximum residual error The maximum residual error is the tolerable mass balance error which should be low but sufficiently high that the number of iterations is not excessive A value of 0 001m d is usually good for regional groundwater studies In smaller scale applications where solute transport will be investigated the mass balance criteria should be reduced for example to 0 0001 or 0 00001m d In gen
259. izontal hydraulic conductivity as low as 1x10 m s which is 5 orders of magnitude The vertical hydraulic conductivity is typically 5 to 10 times lower than the horizontal hydraulic conductivity Related Items e Geological Units V 2 p 108 e Horizontal Hydraulic Conductivity V2 p 112 e Working with Lenses V 1 p 52 113 a Setup Data Tab 2 16 12 Specific Yield Specific Yield dialogue Type Stationary Real Data EUM Data Units Specific Yield In an unconfined aquifer the Specific Yield is defined as the volume of water released per unit surface area of aquifer per unit decline in head The specific yield is much higher than the Specific Storage because the water that is released is primarily from the dewatering of the pores at the water table This results in a unit of L3 L2 L which is dimensionless The Specific Yield is only used in transient simulations but must always be input Furthermore the specific yield is only used in the cells that con tain the water table In the cells below the water table the Specific Storage is used Related Items e Geological Units V2 p 108 e Working with Lenses VJ p 52 2 16 13 Specific Storage Specific Storage dialogue Type Stationary Real Data EUM Data Units Elastic Storage In a confined aquifer the specific storage is defined as the volume of water released per volume of aquifer per unit decline in head This is slightly different than the
260. k V 2 p 234 14 1 3 Connecting MIKE 11 Water Levels and Flows to MIKE SHE In MIKE 11 every node in the river network requires information on the river hydraulics such as cross section and roughness factors These nodes are known as H points and MIKE 11 calculates the water level at every H point node in the river network Halfway between each H point is a Storing Q point where MIKE 11 calculates the flow which must be con stant between the H points The water levels at the MIKE 11 H points are transferred to the MIKE SHE river links using a 2 point interpolation scheme That is the water 232 MIKE SHE Coupling of MIKE SHE and MIKE 11 LEA level in each river link is interpolated from the two nearest H points cal culated from the centre of the link The interpolation is proportionally dis tance weighted The volume of water stored in a river link is based on a sharing of the water in the nearest H points In Figure 14 3 River Link A includes all the water volume from H points 1 and 2 plus part of the volume associated with H point 3 The volume in River Link B is only related to the volume in H point 3 While the volume in River Link C includes water from H points 3 and 4 This is done to ensure consistency between the river vol umes in MIKE 11 and MIKE SHE as the amount of water that can infil trate is limited by the amount of water stored in the river link MIKE SHE river links e e e e MIKE 1
261. l parameters for the MODPATH simulation must be spec ified Start date This is the both the start date for the MODPATH simulation and the saved time step date from the WM simulation to be used as the steady state flow field Thus the Start date must be within the WM simu lation period The start date format follows the format defined in your Regional Settings for Windows End date MODPATH will terminate when the End date is reached or when all of the particles have been removed by sinks The end date format follows the format defined in your Regional Settings for Windows Storing frequency MODPATH will store the particle locations at this frequency The storing frequency must be input in Years This value has not yet been connected to the EUM system Sink strength The sink strength controls how strongly boundary condi tions that remove water will also remove particles A sink strength of 1 means that all particles will be removed when they enter the cell A sink strength of 0 means than none will be removed For more information on the Sink Strength parameter please refer to the MODPATH documenta tion Path Line direction MODPATH can track the particle path lines for ward in time or backward in time In other words the initial particle loca tion can be either a starting point or an ending point for the path line 198 MIKE SHE Simulation Tab LRA 9 4 3 Particles 118756 228258 ES 156336 24452
262. laver E E T een E A Oe Sib E E E E SNE DEEE T Waler buble Maximum depth for transpiration Root Depth ET Lower ET layer only exists when water table is below this level Average soil moisture in lower ET layer Figure 16 5 Soil moisture ranges for different depths to water table If the water table is at the ground surface then the moisture content equals the saturated moisture content 0 and all ET is taken from the saturated zone If the water table is below the ground surface but above the ET surface then the average moisture content of the ET layer is a linear function of the depth of the water table That is the average moisture content in the ET layer is lower when the water table is lower If the water table is above the ET surface the capillary fringe reaches the ground surface In this case the water content is not dependent on ET and any water lost to ET will be replaced from the groundwater table through capillary action If the water table is below the ET surface but above the ET extinction depth then the average water content will vary between a minimum Onin and a maximum Omax Omax 1S the water content that would be present if no ET occurred 0 is the minimum water content that can exist in the upper ET layer when ET is active Both Onin and 9 vary linearly with the depth to the water table That is 9 and Omax are lower when the water table is lower The difference between Oax and
263. lculated automati cally as part of the outer iteration loop The algorithm determines the factors based on the minimum residual 2 norm value found for 4 dif ferent factors To avoid numerical oscillations the factor is determined as 90 of the factor used in the previous iteration and 10 of the cur rent optimal factor The second option is to define a constant relaxation factor between 0 and 1 In general a low value will provide convergence but at a low 43 a a Setup Data Tab convergence rate i e with many SZ iterations Higher values increases the convergence rates but also the risk of non convergence As a general rule a value of 0 2 has been found suitable for most set ups The time used for automatic estimation of relaxation factors may be significant compared to subsequently solving the equations and the option is only recommended in steady state cases In transient simula tions No under relaxation is recommended Successive Over relaxation Over telaxation Relaxation factor 1 0 2 0 t3 Variable Dimensions Relaxation Factor Over relaxation Relaxation factor The speed of convergence also depends on the relaxa tion coefficient Before you set up your model for a long simulation you should test the iteration procedure by running a few short simula tions with different relaxation coefficients This coefficient must be between 1 0 and 2 0 with a typical value between 1 3 an
264. le and the procedure stops The adjustment required to obtain a value of zero is calculated using a secant line approach 5 Anew recharge rate q is calculated taking the adjustments into account n 1 n l q h h S At 16 31 u u where h is the new water table elevation after step d calculated by the UZ module and At is the length of the current UZ time step n If SZ outflows for the next SZ time step ng 1 are unchanged the water table from the SZ calculation will be h h calculated in the last UZ time step before an SZ time step see Eq 16 31 If h h S At gt dmaxs Where gmax iS a Maximum infiltration rate the corrected rate is reduced to Gjqx In the Richards Equation and Gravity Flow options qmax is 0 7K and 0 4K for rising and falling water table conditions respectively where K is the saturated hydraulic conductivity of the UZ node at the water table In the Two layer UZ option the infiltration rate is used to constrain the corrected rate MIKE SHE Coupling the Unsaturated Zone to the Saturated Zone LAA Steps 1 5 are repeated for all UZ time steps within each SZ time step The flows are accumulated and passed as an average rate q for the next SZ time step The average q is used as a flux boundary condition in the SZ differential equations 16 6 2 Limitations The coupling between UZ and SZ is limited to the upper most calculation layer of the saturated zon
265. le is applied This allows you to define for example a distributed global source file say of the field scale agricultural inputs in your catchment and run individual water quality scenarios for each sub catchment modelled as an partial extent to assess the subcatch ment contributions to the global stream impact Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Solute Transport in the Unsaturated Zone V 2 p 340 e Solute Transport in Overland Flow V 2 p 344 132 MIKE SHE Sources 2 17 2 Top Elevation Top Elevation Conditions If source location is Subsurface dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground The Top Elevation refers to the upper elevation of a solute source It is used by the interpolation algorithm to assign a source location to the satu rated or unsaturated zone cells Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Source Sinks Boundary Conditions and other Exchanges V 2 p 338 in the saturated zone e Solute Transport in the Unsaturated Zone V 2 p 340 e Source Sinks Boundary Conditions and other Exchanges V 2 p 343 in the unsaturated zone 2 17 3 Bottom Elevation Bottom Elevation Conditions If source location is Subsurface dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground The Bottom Elevation refers to the lower elevation of a solute so
266. le is below the river level then da is the depth of water in the river e If the river cross section crosses multiple model layers then da and therefore C is limited by the available saturated thickness in each layer The exchange with each layer is calculated independently based on the da calculated for each layer This makes the total exchange inde pendent of the number of layers the river intersects This formulation for da assumes that the river aquifer exchange is prima rily via the river banks which is consistent with the limitation that there is no unsaturated flow calculated beneath the river 14 2 4 Steady state groundwater simulations For steady state groundwater models MIKE 11 is not actually run Rather the initial water level in MIKE 11 is used for calculating da in the con ductance formulas and h for the head gradient To improve numerical stability during steady state groundwater simula tions the actual conductance used in the current iteration is an average of the currently calculated conductance and the conductance used in the pre vious iteration Canyon option for steady state groundwater simulations In the case of a deep narrow channel crossing multiple model layers the head difference used in Equations 14 1 and 14 2 can optionally be lim ited by the bottom elevation of the layer Thus Ah h ia max h iy Z 14 7 where zis the bottom of the current layer The above formulation reduces t
267. level is at the bottom of the reservoir there is no percolation Combining Eqs 17 37 and 17 38 with the continuity equation dh _ 9 infit 11 Ipere dt S y 17 39 where S is the specific yield gives the following expression for h at time t when there is both qy and qperc linear reservoir with two outlets k k dt k k d kk S kik ura i e kik S i p y toe Te ey tn k 17 40 In the case where the water level is below the threshold the formulation for a linear reservoir with one outlet applies which yields dt dt kS kS h hye tam Ie 17 41 Specific infiltration qini will normally by positive i e water will be being added but if evapotranspiration from the saturated zone is included or the net precipitation is used as input there might be a net discharge of water from the interflow reservoir As the infiltration is a constant rate cal culated explicitly in other parts of MIKE SHE this will result in a water balance error if the interflow reservoir is empty This will be reported in the log file at the end of the simulation 314 MIKE SHE Linear Reservoir Method a oe From the level changes in the reservoir the total average outflow can be calculated for the time step dt Thus for the two outlet case lout h hy S dt dingit 17 42 k qi k y p Pou hinresn Kp 17 43 Apere fouir 17 44 and for the single outlet case n
268. links that neighbour the model cells in the lowest topographical zone in each subcatchment Interflow will be added as lateral flow to river links located in the lowest interflow storage in each catchment Similarly baseflow is added to river links located within the baseflow storage area The infiltrating water from the unsaturated zone may either contribute to the baseflow or move laterally as interflow towards the stream Hence the Technical Reference for Water Movement 309 Saturated Flow Reference RAIN AND SNOW INPUT CANOPY INTERCEPTION MODEL DISTRIBUTED SNOWMELT MODEL OVERLAND N FLOW AND OW ork ROOT ZONE OVERLAND AND CHANNEL PROCESSES GRID SQUAR AGGREGATION OF ROOT ZONE PERCOLATION WITHIN TOPO GRAPHICAL ZONES FOR LUMPED ROUTING OF INTERFLOW AND BASEFLOW INTERFLOW STORAGES BASEFLOW STORAGES BASE gt FLOW Figure 17 8 Model Structure for MIKE SHE with the linear reservoir module for the saturated zone interflow reservoirs have two outlets one outlet contributes to the next interflow reservoir or the river and the other contributes to the baseflow reservoirs The baseflow reservoirs which only have one outlet are not interconnected Normally one reservoir should be sufficient for modelling baseflow satis factorily However in some cases for example in a large catchment hydraulic contact with a river is unlikely to be present everywhere In
269. list changes in response to the processes included in the Simulation Specification dialogue Further additional items are availa ble that are related to simulation variables such as the number of itera tions during each Saturated Zone time step A list of available Data Types can be found in Output Items V 1 p 87 New plot If this is checked then the a new detailed time series HTML plot will be created on the Results Tab If this is unchecked then the 138 MIKE SHE Storing of Results Se output will be added to the previous plot You can use the Up and Down arrows to arrange the output points so that relevant points are plotted together X Y Often detailed time series are associated with measurement sta tions That is locations at which a time series of measurements are available for example water levels in a well or water depths on a flood plain This is the X Y map coordinates of the point in the same EUM units ft m etc as specified in the EUM Database for Item geometry 2 dimensional see EUM Data Units Depth This is the depth of the observation point below land surface for subsurface observation points The value is in same EUM units ft m etc as specified in the EUM Database for Depth Below Ground see EUM Data Units Target Icon You can use the target icon to locate the output point exactly Alternatively you can type the exact coordinates or import the items from an ASCII file Includ
270. lity 341 LEA Advection Dispersion Reference Figure 19 5 Control volume defining an internal grid For the control volume shown in Figure 19 5 this equation is written in finite difference form as cH et a les e0 i i A ys in 19 21 where n denotes the time index c is the concentration in the computa tional node c is the interpolated concentration at the edges of the grid at time n and o is the directional Courant number defined by v At ioe 19 22 As the c terms are not located at the nodal points they have to be inter polated from known concentration values The equation for this follows the one derived for the saturated zone ATAA ci 19 23 342 MIKE SHE User s Guide Solute Transport in the Unsaturated Zone LAA However in the unsaturated zone only three weights need to be deter mined aii oE ad Sree a f 2 3 De p AS p a a GG 19 24 where the weights are positioned relative to the actual flow direction Dispersive transport can be derived in a similar way If the finite differ ence formulation of the dispersive transport is based on upstream differ encing in concentration and central differencing in the dispersion coefficients the dispersive transport is TDa Dzn Dea crr cV z wul 19 25 The dispersive transport is incorporated into the weights The above solution is strictly speaking only valid for a regular discretisa tion but if the
271. llary fringe Thus if the water table is below the ET extinction depth then water removed from the root zone by ET cannot be replaced by water drawn up by capillary action since the roots do not reach the top of the capillary fringe The depth of the root zone is specified in MIKE SHE s crop database and can vary in time and space The simplified ET module assumes that the unsaturated zone can consist of one or two layers The upper layer extends from the ground surface to the higher of the water table or the ET extinction depth The second layer extends from the bottom of first layer to the water table if the water table is below the ET extinction depth Thus if the water table is above the ET extinction depth the thickness of the lower layer is zero If the water table is at the ground surface then the thickness of the upper layer is also zero ET is only allowed from the upper of the two ET layers if the lower layer exists Moisture Content Ow On Hs Trent TT at thickness of capillary rinse hiskuess ut rias Depth of Waler Tuhk O uex Por a particular depth to wares table the soil moisture can wars beret Cin 0d Gren a E ig Poem x thickness of capillary tinge ET extinction depth Hticktiess al rols Figure 15 9 Allowable range for soil moisture in the upper ET layer for a given depth to water table 256 MIKE SHE Simplified ET for the Two Layer Water Balance Method a oe Range tor average so
272. lumn cum time step If E 2 1 less than Emax Corrections are not made for the current UZ cum 4 If E 1 exceeds Emax the following corrections are made a If E is negative or positive the water table is raised or low cum ered respectively in prescribed increments that depend on the dis Technical Reference for Water Movement 285 Unsaturated Flow Reference tance between UZ nodes and the UZ calculation in time step n to n l is repeated as described above b In the Full Richards solution the UZ flow solution is repeated for the last three nodes above the water table to reduce numerical over head In the Gravity Flow option the UZ flow solution is repeated for the entire column The UZ flow solution is not repeated for the two layer UZ option c The change in water volume W t over the entire column is computed and a new E is calculated cum cum factor equal to 0 9 the error associated with the solution is consid ered acceptable and the procedure stops If E is greater than or equal to a E nq the solution is unacceptable and steps a through d are repeated until criteria d is satisfied The value a defines a threshold for stopping the procedure lower than that used to initiate the procedure which prevents correction overshoots d If is less than a Emax Where a is a hard coded correction e If changes sign the solution is considered acceptab
273. m by dropping the last three terms of the momentum equa tion Thereby we are ignoring momentum losses due to local and convective acceleration and lateral inflows perpendicular to the flow direction This is known as the diffusive wave approximation which is implemented in MIKE SHE Considering only flow in the x direction the diffusive wave approximation is oo h Oyoh a Ox Ox xx 13 3 If we further simplify Equation 13 3 using the relationship z z hit reduces to Oz S h 13 4 Ox a Ox 13 4 in the x direction In the y direction Equation 13 4 becomes Oz S z h 13 5 Use of the diffusive wave approximation allows the depth of flow to vary significantly between neighbouring cells and backwater conditions to be simulated However as with any numerical solution of non linear differ ential equations numerical problems can occur when the slope of the water surface profile is very shallow and the velocities are very low Now if a Strickler Manning type law for each friction slope is used with Strickler coefficients K and Ky in the two directions then 2 S fx 13 6a Ww 24 3 Kh 2 v 9 Kht 13 6b 212 MIKE SHE Finite Difference Method Se Substituting Equations 13 4 and 13 5 into Equations 13 6a and 13 6b results in uo _ amp K2n4 3 Ox ve _ _ amp K2n43 dy 13 7a 13 7b After simplifying Equations 13 7a and 13 7b and mult
274. mainder A chemical formulation of this approach is given by corer 20 9 where c is the amount of the solutes sorbed described by the equilibrium sorption model c is the amount of the sorbed matter that is converted to the kinetically controlled sorption domain Mathematically the work of Brusseau 1995 is implemented in MIKE SHE AD as g ne E ot tees 20 10 where K is the constant defining the rate of kinetic sorption The formula is generalised so that effects of hysteresis can be taken into account by specifying a K value for adsorption c gt c and another value for des orption c gt c The formula is generally applicable for all the equilibrium sorption mod els All constants appearing in the sorption models are assumed constant in time but may vary in space 20 1 3 Sorption in Dual Porosity Systems Sorption depends on the porosity and the bulk density of the soil In dual porosity systems this is rather complicated The distribution of sorption between the matrix and the fractures should be calculated based on the bulk density and different porosities However this is not always practi cally possible so MIKE SHE has included a sorption bias factor Fy This allows you to explicitly control the sorption distribution between the fractures and the matrix Technical Reference for Water Quality 355 Reactive Transport Reference 20 2 Decay Mathematically the bulk mass available for
275. mbined with the Richards Equation description for the UZ because the simple feedback mecha nism to the UZ based on field capacity replaces the exchange with the unsaturated zone due to capillarity Technical Reference for Water Movement 319 Saturated Flow Reference 320 MIKE SHE TECHNICAL REFERENCE FOR WATER QUALITY 321 322 MIKE SHE User s Guide Se 18 WATER QUALITY OVERVIEW This section includes detailed descriptions of the numeric engines used for moving water in MIKE SHE including e Advection Dispersion Reference p 325 e Reactive Transport Reference p 351 e Particle Tracking Reference p 369 Technical Reference for Water Quality 323 on Water Quality Overview 324 MIKE SHE User s Guide Simulation control LAA 19 ADVECTION DISPERSION REFERENCE 19 1 Simulation control In the MIKE SHE water movement module you can calculate solute transport in the different parts of the hydrological cycle In the present ver sion of MIKE SHE AD only three combinations are legal groundwater transport can run as a stand alone module e groundwater transport can be run in combination with the overland transport module and e all modules in combination can run Thus a simulation with only overland or only the unsaturated zone is not possible and that combinations of the unsaturated zone with only the over land or groundwater component are
276. more water released at low matrix potential and the greater the root density the higher should the value of C3 be Further dis cussion is given in Kristensen and Jensen 1975 252 MIKE SHE Kristensen and Jensen method a oe c1 c2 C1 C2 0 5 C2 C1 0 31 0 75 0 75 0 5 0 5 0 25 0 25 0 20 40 60 80 100 Evapotranspiration Figure 15 7 The influence of the C and C on the ratio between soil evaporation and transpiration The values were obtained from model runs assuming Cin 0 the moisture content above field capacity and LAI 5 Evapotranspiration 0 25 50 75 100 0 L L L 25 2 s 50 4 Q o a C2 0 5 75 4 C2 0 2 4 C2 0 1 gt C2 0 0 100 Figure 15 8 Distribution of actual evapotranspiration in per cent over depth for different values of Cz C2 0 corresponds to pure transpiration Technical Reference for Water Movement 253 LEA Evapotranspiration Reference 15 2 Simplified ET for the Two Layer Water Balance Method The Two Layer Water Balance Method is an alternative to the more com plex unsaturated flow process coupled to the Kristensen and Jensen mod ule for describing evapotranspiration The Simplified ET for the Two Layer Water Balance Method is based on a formulation presented in Yan and Smith 1994 The main purpose of the module is to calculate actual evapotranspiration and the amount of water that
277. mple of simu lated soil temperature distributions as a function soil depth is shown in Figure 20 4 MIKE SHE allows you to specify separate half lifes for the matrix and fractions in dual porosity models since degradation is likely to be faster in the fractures where higher oxygen contents are more likely 358 MIKE SHE User s Guide Plant Uptake a oa Simulated measured 2 measured 1 SEP OCT Nov DEC JAN FEB MAR APR MAY JUN 1994 1995 ge Air temperature and simulated soil temperature soil 2 0 m soll Losin soil 0 5 m ar nt Ag R 2 Figure 20 4 Application of the soil temperature function Top measured and sim ulated soil temperature in 30 cm depth measurements were based on two replicates Bottom soil temperatures simulated in different depths based on measured air temperatures 20 3 Plant Uptake Plant uptake of solutes is described as passive transport along with the transpiration stream as a function of the solute concentration in the liquid phase Different roots have different capabilities when it comes to filtering Technical Reference for Water Quality 359 Reactive Transport Reference out various solutes Thus an empirical concentration factor determines to what extent the available solute is taken up by the plants Rr S Je dre f 20 18 where R is the sink term in the advection dispersion equation f is the concentration factor S
278. mum head difference between 0 05 and 0 1 metres The default minimum head difference is 0 1 Higher values may lead to a diver gence from the Mannings solution Lower values may lead to more accurate solutions but at the expense of numerical instabilities smaller time steps and longer simulation times For a detailed discussion of the damping function see the Low gradient damping function V2 p 218 Related Items e Low gradient damping function V 2 p 2 8 e Overland Flow Reference V 2 p 211 38 MIKE SHE Simulation Specification LEA 2 2 5 UZ Computational Control Parameters UZ SZ Coupling Control Full Richards and Simple UZ Max profile water balance error 0 001 m Full Richards Solution Iteration Control Maximum no of iterations 50 Iteration stop criteria fraction of Psi 0 002 Timestep Reduction Control UZ Restart Max water balance error in one node fraction 10 03 UZ Computational Control Parameters Conditions if Unsaturated Flow specified in Model Components Variable Units Maximum profile water balance error EUM water level Maximum number of iterations Iteration Stop criteria Maximum water balance error in one node m The unsaturated flow is solved iteratively when the Richards Equation method is chosen but is solved directly for both the Gravity Flow module and the Two Layer Water Balance methods When the Richards Equation method is used
279. n 17 2 Linear Reservoir Method The linear reservoir module for the saturated zone in MIKE SHE was developed to provide an alternative to the physically based fully distrib uted model approach In many cases the complexity of a natural catch ment area poses a problem with respect to data availability parameter estimation and computational requirements In developing countries in particular very limited information on catchment characteristics is availa ble Satellite data may increasingly provide surface data estimates for veg etation cover soil moisture snow cover and evaporation in a catchment However subsurface information is generally very sparse In many cases subsurface flow can be described satisfactorily by a lumped conceptual approach such as the linear reservoir method The MIKE SHE modelling system used with the linear reservoir module for the saturated zone may be viewed as a compromise between limita tions on data availability the complexity of hydrological response at the catchment scale and the advantages of model simplicity The combined lumped physically distributed model was primarily developed to provide a reliable efficient instrument in the following fields of application e Assessment of water balance and simulation of runoff for ungauged catchments e Prediction of hydrological effects of land use changes Technical Reference for Water Movement 307 Se Saturated Flow Reference e Flood
280. n additional item the Geological Unit Distribution in the data tree Related Items e Saturated Flow Reference V 2 p 289 109 Se Setup Data Tab 2 16 5 Geological Lenses m Geological Layers mo Upper Clay Lense For each geologic layer you must specify the hydrogeologic parameters 0 f the layer including Lower Level Geological Layer or Lense or Water Quality Layer Upper Level Horizontal Extent Horizontal Hydraulic Conductivity Vertical Hydraulic Conductivity Specific Yield Specific Storage If you define your hydrogeology by then most of the physical properties will be defined as properties of the Geological Unit and there will be an additional item the Geological Unit Distribution in the data tree Related Items Working with Lenses V 1 p 52 110 MIKE SHE Saturated Zone es 2 16 6 Lower Level Geological Layer or Lense or Water Quality Layer Lower Level dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground The Lower Level value is used to define the bottom of geological layers geological lenses and water quality layers The bottom of geological or water quality layer is always equal to the top of the layer underneath In the case of geological lenses the lower level is used in the interpolation algorithm to interpolate geological properties to the model cells Related Items e Working with Lenses V
281. n 100 and 10 respectively Generally lower values of Mannings M are used for overland flow compared to channel flow Detention Storage Detention Storage is used to limit the amount of water that can flow over the ground surface For example if the deten tion storage is set equal to 2mm then the depth of water on the surface must exceed 2mm before it will be able to flow as overland flow Water trapped in detention storage continues to be available for infiltration to the unsaturated zone and to evapotranspiration Using detention stor age you can simulate water that is trapped in depressions that are smaller in area than a grid cell Initial Depth This is the initial condition for the overland flow calcula tions that is the initial depth of water on the ground surface Related Items e Simplified Overland Flow Routing V 2 p 220 e Overland Flow Reference V 2 p 211 MIKE SHE Overland Flow LEA 2 13 7 Dispersion coefficient along columns rows Dispersion coefficient along columns rows Condition when water quality for Overland Flow is selected in the Water Quality Simulation Specification dialogue dialogue Type Stationary Real Data EUM Data Units Dispersion coefficient For the overland flow transport two dispersion coefficients are required one along the rows and the other along the columns Note Unlike for the unsaturated and saturated flow the overland transport module requires the actual
282. n can be started from a hot start file A hot start file is useful for simulations requiring a long warm up period or for generating initial conditions for scenario analysis To start a model from a previous 28 MIKE SHE Simulation Specification LEA model run you must first save the hot start data in the Storing of Results V 2 p 135 dialogue Hot start date The hot start information is saved at specified intervals and the list of hot start dates is automatically filled in from the hot start file Use Hot start date for simulation start date if you select this option the simulation start date is greyed out and the simulation starts from the selected hot start date Otherwise you are free to chose an independent starting date and only the hot start data is simply used as initial condi tions Related Items e Storing of Results V 2 p 135 29 a oa Setup Data Tab 2 2 3 Time Step Control Time Steps Initial time step ay hrs Max allowed OL time step ps 3 hrs Max allowed UZ time step B hrs Max allowed SZ time step z o hrs M Increment of reduced time step length Increment rate 0 1 0 05 Parameters for Precipitation dependent time step control Max precipitation depth per time step fi 0 mm Mas infiltration amount per time step fi 0 mm Input precipitation rate requiring its fo 1 mmhr own time step Time Step Control Conditions Maximum OL UZ
283. n equation which for a porous medium with uniform poros ity is ge P 2 2 dc evi Dy Re A aad fr Ox Ox O x 19 3 where c is the concentration of the solute Rc is the sum of the sources and sinks Dj is the dispersion coefficient tensor and v is the velocity tensor The advective transport is determined by the water fluxes Darcy veloci ties calculated during a MIKE SHE WM simulation To determine the groundwater velocity the Darcy velocity is divided by the effective poros ity pee 19 4 where q is the Darcy velocity vector and 0 is the effective porosity of the medium The mathematical formulation of the dispersion of the solutes follows the traditional formulations generalised to three dimensions This formula was developed assuming that the dispersion coefficient is a linear function of the mean velocity of the solutes In the three dimensional case of arbitrary flow direction in an anisotropic aquifer the dispersion tensor D contains nine elements giving a total of 36 dispersivities The general formulation of the dispersion tensor is derived in Scheidegger 1961 and can be writ ten as D Yam 19 5 ij Giimn U where djjm is the dispersivity of the porous medium a fourth order ten sor v and v are the velocity components and U is the magnitude of the velocity vector The derivation of Dj and dj in MIKE SHE follows the work of Bear and Verruijt 1987 Two simplification
284. n technique and the PCG groundwater solver based on a precondi tioned conjugate gradient solution technique The formulation of potential flow and sink source terms differs between the two modules to some extent The Saturated Zone Component interacts with the other components of MIKE SHE WM mainly by using the boundary flows from other compo nents implicitly or explicitly as sources and sinks 17 1 3D Finite Difference Method The governing flow equation for three dimensional saturated flow in satu rated porous media is oh oh oh oh Cee i So S Keg oy 17 1 where K x Kyy K the hydraulic conductivity along the x y and z axes of the model which are assumed to be parallel to the principle axes of hydraulic conductivity tensor h is the hydraulic head Q represents the source sink terms and S is the specific storage coefficient Two special features of this apparently straightforward elliptic equation should be noted First the equations are non linear when flow is uncon fined and second the storage coefficient is not constant but switches between the specific storage coefficient for confined conditions and the specific yield for unconfined conditions Technical Reference for Water Movement 289 LEA Saturated Flow Reference 17 1 1 The Pre conditioned Conjugate Gradient PCG Solver As an alternative to the SOR solver MIKE SHE s groundwater compo nent also includes the pre conditioned conj
285. n the MIKE 11 model However this is not checked until run time at which point an error message will be generated if it is not valid and the simu lation will be stopped Chainage like the branch name the chainage must be a valid MIKE 11 chainage Include observation data If this is checked then a dfsO file can be specified that includes observation points The observation points are automatically plotted along with the results in the HTML plot on the Results tab The dfsO item is selected in the file browser dialogue The Edit button opens the specified dfsO file and the New button can be 141 LEA Setup Data Tab used to create a new dfs0 file with the correct item type etc and at the same time import data from an Excel spreadsheet Importing data Detailed MIKE 11 Time Series data can be imported directly into the Detailed MIKE 11 Time Series dialogue using the Import button The data file must be a tab delimited ASCII file without a header line The file must contain the following fields and be in the format specified below Name gt DataTypeCode gt BranchName gt Chainage gt UseObsdata gt dfs0file name gt dfsOItemNumber where the gt symbol denotes the Tab character and Name is the user specified name of the observation point This is the name that will be used for the time series item in the Dfs0 file created during the simulation DataTypeCode This is a numeric code used to identify the output data type
286. nates of the source well Max depth to water this is the threshold value for the water depth in the well If the water level in the well falls below this depth as measured from the topography the extraction will stop until the water level rises above the threshold Max rate This is the maximum extraction rate for the well If more water is required for irrigation then the next source will be activated Top Bottom of Screen The depth of the top and bottom of the screen is used to define from which numerical layers water can be extracted Pumping will stop if the water table falls below the bottom of the layer that contains the filter bottom There is no restriction on the number of wells at a location However if the wells are located in the same model grid and have overlapping screen intervals then a warning message will be printed to the projectname_preprocesssor_messages log file The sources will be merged retaining the maximum threshold depth the sum of the capacities and the joint screening interval The preprocessor also checks the license application volume to make sure these are the same If not the preproces sor will stop with an error In the linear reservoir groundwater method multiple single wells are allowed in each baseflow reservoir No warnings are given When the linear reservoir method is used the screen interval is ignored and the water is pumped from the two baseflow reservoirs The distribu tion betwe
287. nce the ratio approaches the basic ratio determined by C and the input value of LAI C2 For agricultural crops and grass grown on clayey loamy soils Cy has been estimated to be about 0 2 Similar to C4 C influences the distribution between soil evaporation and transpiration as shown in Figure 15 8 For higher values of C5 a larger percentage of the actual ET will be soil evap oration Since soil evaporation only occurs from the upper most node closest to the ground surface in the UZ soil profile water extraction from the top node is weighted higher This is illustrated in Figure 15 8 where 23 per cent and 61 per cent of the total extraction takes place in the top node for C values of 0 and 0 5 respectively Thus changing C will influence the ratio of soil evaporation to transpira tion which in turn will influence the total actual evapotranspiration possi ble under dry conditions Higher values of C will lead to smaller values of total actual evapotranspiration because more water will be extracted from the top node which subsequently dries out faster Therefore the total actual evapotranspiration will become sensitive to the ability of the soil to draw water upwards via capillary action C3 C has not been evaluated experimentally Typically a value for C3 of 20 mm day is used which is somewhat higher than the value of 10 mm day proposed by Kristensen and Jensen 1975 C may depend on soil type and root density The
288. nciple parameters that must be defined for each soil type Soil water content at saturation this is the maximum water con tent of the soil which is usually approximately equal to the poros ity Soil water content at field capacity this is the water content at which vertical flow becomes negligible It practice this is the water content that is reached when the soil can freely drain Although it is usually higher than the residual saturation which is usually defined as the minimum saturation that can be achieved in a laboratory test 99 Setup Data Tab Soil water content at the field wilting point this is the lowest water content that plants can extract water from the soil Infiltration rate this is the saturated hydraulic conductivity of the soil Bypass Constants The bypass parameters include byp the maximum bypass fraction between 0 and 1 0 of the net rainfall thr1 6 the threshold water content below which the bypass frac tion is reduced and thr2 02 the minimum water content at which bypass occurs Related Items e Unsaturated Flow Reference V 2 p 261 e Two Layer Water Balance V 2 p 275 e Simplified Macropore Flow bypass flow V 2 p 280 2 14 7 ET Surface Depth ET Surface Depth Conditions when Unsaturated Flow selected in the Simulation Specification dialogue and the Two Layer Water Bal ance method selected for the numeric engine dialogue Type Stationary Re
289. nclude detailed analysis of the t0 file for mat so finding the errors can be somewhat tricky If you encounter an error such as Error reading header information of TO file or an error related to the end of file or missing time series data then this is often related to missing information in the tO file Check that all fields in the tO file are complete and that there are no extraneous fields Also ensure that the well name is enclosed in quotation marks Importing TAB delimited text file The most common file format to import is a TAB delimited ASCII file typically generated from Excel or a database program The only restriction on the import is that only one screened interval can be specified for each well Addition screened intervals must be specified manually after the wells have been imported Below is the format that each line in the ASCII file must follow Well_ID gt X gt Y gt Level gt Depth gt Well_Field gt Top gt Bottom gt Fraction gt dfs0_File gt dfs0_item CW1 7780 00 20331 00 0 00 0 00 CW O 60 1 CW2 8000 00 19000 00 0 00 0 00 CW 10 50 0 5 Time ClassPumpage dfs0 3 CW3 7600 00 21300 00 0 00 0 00 CW 10 60 1 A simple example with three groundwater wells is given below Time ClassPumpage dfs0O 1 Time ClassPumpage dfs0 2 172 MIKE SHE Soil Moisture Retention Curve a oe 6 UZ SOIL PROPERTIES EDITOR To solve Richards equation two important hydraulic functions are required fo
290. nd component is a one way transport from the overland to the unsaturated zone whereas both transport to and from the groundwater can occur Point and line sources can be included with units of mass time Spatially distributed sources can be included with units of mass area time In each calculation time step the solute mass in all grids nodes is updated with mass from the source It is not possible to introduce external sinks in the unsaturated zone How ever water can be removed by the roots or via soil evaporation which can consequently increase solute concentrations 19 4 Solute Transport in Overland Flow MIKE SHE calculates the movement of solutes in overland flow when ever ponded water exists In surface water the mixing and spreading of solutes is mainly due to turbulence which appears when the flow velocity exceeds a certain level This process is known as turbulent diffusion and is generally far more important than molecular diffusion Although this proc ess is physically different from the spreading of solutes in groundwater solute transport in surface water is usually still described using the advec tion dispersion equation Similar to the saturated zone the 2D advection dispersion equation for overland transport is solved using the explicit third order accurate QUICKEST scheme As for solute transport in the saturated zone the dispersion coefficients depend on the spatial and temporal scale of averaging However dispe
291. nd has been applied in other codes such as the WATBAL model Knudsen J 1985a b Refsgaard and Knudsen 1996 In the following a description of the principles behind the model and the governing equations implemented and solved in MIKE SHE are pre sented It is implicitly assumed that the equations derived for a hill slope can be applied to describe overland flow in a lumped manner across a catchment 13 2 1 Theoretical basis Figure 13 4 Schematic of overland flow on a plane Figure 13 4 represents a schematic of overland flow on a planar surface of infinite width with uniform rainfall Precipitation falls on the plane builds on the surface in response to the surface roughness and flows down the slope in the positive x direction In the figure L is the length of the slope y is the local depth of water on the surface at any point along the surface and a is the slope Then from the continuity equation OF p Tsk 13 20 220 MIKE SHE Simplified Overland Flow Routing LEA where q is the specific discharge For turbulent flow on a plane of infinite width the Manning equation is q M y dJa m s 13 21 where M is the Mannings M Now at equilibrium the depth no longer changes and the specific dis charge approaches the rainfall rate Gy _ 9542 R a OS a TRP LER x 13 22 where qe is the equilibrium specific discharge Then at equilibrium the volume of water detained on the surface D can
292. ne occurs if the water table rises above the ground surface A spatially distributed source is specified using a dfs2 file where the source strength is given in units of mass area time It is not possible to introduce external sinks for overland transport How ever solute concentrations can increase due to evaporation 19 5 Solute Transport in MIKE 11 In MIKE SHE the solute transport in the river channels is handled by the MIKE 11 Advection Dispersion AD module In MIKE 11 the 1D advection dispersion equation is solved using an implicit finite difference scheme that is in principle unconditionally sta ble with negligible numerical dispersion A correction term has been added to reduce the third order truncation error making it possible to sim ulate very steep concentration gradients Longitudinal dispersion in channels is largely controlled by the non uni form velocity distribution both spatially and temporally In rivers the dis persion coefficient is normally on the order of 5 to 10 m2 s increasing to between 30 and 100 m2 s when 2D processes such as secondary currents and wind induced turbulence begin to dominate MIKE 11 exchanges solutes with MIKE SHE s overland and saturated zone flow components 348 MIKE SHE User s Guide Solute Transport in MIKE 11 a oe Detailed information on this module is available as part of the MIKE 11 technical documentation which can be found in pdf form in your install
293. nitial condition for the overland flow calculations that is the initial depth of water on the ground surface The initial water depth is usu ally zero The initial water depth for overland flow is also the boundary condition for overland flow In other words if you specify an initial depth of 2mm then the boundary will always have 2mm of water and there will be an inflow of water to the model whenever the internal cell has less than 2mm of ponded water Related Items e Adding Overland Flow V 1 p 46 e Overland Flow Reference V 2 p 211 2 13 4 Overland groundwater Leakage Coefficient Overland groundwater Leakage Coefficient Conditions when Overland Flow the Finite Difference method is selected in the Simulation Specification dialogue AND the Reduced contact in subareas option selected in the main Overland Flow dialogue dialogue Type Stationary Real Data EUM Data Units Leakage Coeff Drain Time Const When the soil profile becomes completely saturated MIKE SHE disables the unsaturated zone calculation If at the same time there is ponded water on the ground surface the exchange of water between the overland flow component and the groundwater component is calculated based on the vertical hydraulic conductivity in the upper layer of the saturated zone 85 Setup Data Tab and the hydraulic gradient between the surface water level and the ground water table in the upper layer of the saturated zone Ho
294. nominally lumped in so far as the soil profile that is defined for each soil zone represents some sort of average soil profile in the zone If the depth to the water table is also divided into zones of equal depth then the unsaturated flow needs only be calculated once for each area with the same soil profile and water table depth Such lumping can decrease the computational burden considerably However when the water table is very dynamic and spatially variable Technical Reference for Water Movement 261 Se Unsaturated Flow Reference there may be no choice but to solve the unsaturated flow equations for each cell in the model using the full Richards solution 16 1 Richards Equation The driving force for transport of water in the unsaturated zone is the gra dient of the hydraulic head h which includes a gravitational component z and a pressure component y Thus h z y 16 1 The gravitational head at a point is the elevation of the point above the datum z is positive upwards The reference level for the pressure head component is the atmospheric pressure Under unsaturated conditions the pressure head y is negative due to capillary forces and short range adsorptive forces between the water molecules and the soil matrix These forces are responsible for the retention of water in the soil As these two forces are difficult to separate they are incorporated into the same term Although the physical phenomena
295. not possible 19 1 1 Flow Storing Requirements The transport calculations are based on the water flow water contents hydraulic heads and water levels calculated in a MIKE SHE water move ment simulation Depending on the complexity of the advection disper sion simulation the water movement output must be stored with different storing time steps The selected storing frequency should be sufficient to reflect the dynamics of the flow processes However the following two restrictions must be observed e The SZ head and SZ flow storing time steps must be equal and e The SZ storing time step must be an integer multiple of the UZ storing time step which must be an integer multiple of the overland storing time step The last restriction above is controlled in the user interface 19 1 2 Internal Boundary Conditions If a simulation with MIKE SHE AD includes more than one part of the hydrological cycle the solute fluxes between the different hydrologic components must be kept track of In principle the solute fluxes between the components follow the water flow between the components Multiply ing the flow rate with the solute concentration produces a source sink term for the relevant components Table 19 1 lists the solute exchange possibil Technical Reference for Water Quality 325 Advection Dispersion Reference ities between the components in particular when one or more component is not included in the flow simulation
296. not satisfied water is extracted from the saturated zone The amount that can be extracted is expressed as a function of the depth to the ground water table Esz E At Esan Epon Euz mm zas H he F Zext Za Esz max E t E oon Epon Eug Ep At H gge Het zun ext Esz 0 ay ee where Zex Extinction depth m He ET surface elevation m Zqis considered equal to the root depth Thus Z4 may be time variant Actual ET Finally the actual evapotranspiration can be computed as the sum of the above contributions Ea Ecan Epon Ey Esz mm 15 2 6 Recharge to the Saturated Zone If the average water content Oaet exceeds the maximum water content Omax groundwater recharge QR is produced Qr max Ogct Omax Za Za 0 mm 260 MIKE SHE Simplified ET for the Two Layer Water Balance Method a oe 16 UNSATURATED FLOW REFERENCE Unsaturated flow is one of the central processes in MIKE SHE and in most model applications The unsaturated zone is usually heterogeneous and characterized by cyclic fluctuations in the soil moisture as water is replenished by rainfall and removed by evapotranspiration and recharge to the groundwater table Unsaturated flow is primarily vertical since gravity plays the major role during infiltration Therefore unsaturated flow in MIKE SHE is calculated only vertically in one dimension which is suffi cient for most applications However this may limit the vali
297. nt simulation as the source of the cell by cell flows for the water quality simulation This allows you to use one water quality setup and calculate water quality based on several water move ment scenarios You must be careful though to not overwrite your results files from the previous water quality simulations For more information on the Advection Dispersion Water Quality see 27 LEA Setup Data Tab e Simulating Water Quality VJ p 193 e Advection Dispersion Reference V 2 p 325 2 2 1 Simulation Title Simulation Title Simulation Description Title and Description The Title and Description will be written to out put files and appear on plots of the simulation results 2 2 2 Simulation Period m Hotstart IV Use hot start data Hot start result File C 5 Testing NASaby NrSaby2003 7layer 250b NrS aby2003 Ai Hot start date 1995 1 0 03 00 00 7 r Simulation Period Start Date 139571 0 03 00 00 End Date 1995 11 01 00 00 a x In the MIKE SHE GUL all of the simulation output is in terms of real dates which makes it easy to coordinate the input data e g pumping rates the simulation results e g calculated heads and field observations e g measured water levels The Simulation Period dialogue is primarily used to define the beginning and end of a transient simulation or the beginning and end of the averag ing period for a steady state simulation However the simulatio
298. o interflow Oeri h h y S dt Qingii 17 45 If during a time step the reservoir level crosses one or more thresholds an iterative procedure is used to subdivide the time step and the appropriate formulation is used for each sub time step The discharge to the river Q7 iven in the lowest Interflow Reservoir is sim ply the Qy from that reservoir 17 2 5 Calculation of Interflow Percolation and Dead Zone Storage The inflow to the Baseflow Reservoirs from the Interflow Reservoirs Qin is weighted based on the overlapping areas Thus if the Baseflow and Interflow reservoirs overlap then interflow y Gove OS Pine 17 46 isi 1A asetiow where A interflow 18 the area of the Interflow Reservoir that overlaps with the Baseflow Reservoir Apasefow 1S the area of the Baseflow Reservoir and DZ rac 18 the fraction of the total Q that goes to the dead zone storage Likewise the amount of water going to deadzone storage is given by 1 Vdead S dyere qe DZ rac 17 47 isi baseflow Technical Reference for Water Movement 315 LEA Saturated Flow Reference 17 2 6 Calculation of Baseflow From Eq 17 30 if the water level in the linear reservoir is above the threshold water level 2 h Nehresh dg k 17 48 where h is the depth of water in the baseflow reservoir Ainresn is the depth of water required before baseflow occurs and k is the time constant for baseflow If the water level is belo
299. od V 2 p 211 or a Simplified Overland Flow Routing V 2 p 220 method e Rivers and Lakes see also Channel Flow Reference V 2 p 227 e Unsaturated Flow see also Evapotranspiration Reference V 2 p 243 a 1D Richards Equation V2 p 262 solution asimplified 1D Gravity Flow V 2 p 273 solution or aTwo Layer Water Balance V2 p 275 solution for shallow water tables e Evapotranspiration see also Unsaturated Flow Reference V 2 p 261 and e Saturated Flow see also Saturated Flow Reference V 2 p 289 3D Finite Difference Method V 2 p 289 or aLinear Reservoir Method V 2 p 307 These choices are immediately reflected in the data tree where the appro priate parameters are added or removed There is only one calculation option in this dialogue for Rivers and Lakes because the calculation methods are defined in the MIKE 11 User Inter face Likewise the use of the simple or advanced Evapotranspiration methods are defined by the unsaturated flow method selected Water Quality options Include Advection Dispersion AD Water Quality At the bottom of this dialogue is a checkbox where you can specify whether or not to include water quality in the simulation If checked the data tree will expand to include water quality data items Use Current WM simulation for Water Quality If you uncheck this check box then you will be able to specify a different different water moveme
300. odel performs reasonably well under most condi tions The module includes the processes of interception ponding infiltration evapotranspiration and ground water recharge While MIKE SHE s unsaturated zone module requires a detailed vertical discretisation of the soil profile unsaturated zone the simplified ET module considers the entire unsaturated zone to consist of two layers representing average conditions in the unsaturated zone The input for the model includes the characterisation of the vegetation cover and the physical soil properties The vegetation is described in terms of leaf area index LAD and root depth The soil properties include a con stant infiltration capacity and the soil moisture contents at the wilting point field capacity and saturation The output is an estimate of the actual evapotranspiration and the ground water recharge 16 3 1 Soil Moisture The ET surface ET up is defined as the ground surface less the thickness of the capillary fringe If the water table is above the ET surface then ET will not reduce the moisture content of the soil since any water deficit will be replaced by water drawn up from the saturated zone via capillary action The ET extinction depth is the maximum depth to which water can be removed by transpiration It is defined as the depth of the root zone plus the thickness of the capillary fringe Thus if the water table is below the 276 MIKE SHE Two Layer Wat
301. oint values i e the same as XYZ or shp data Integer Grid Code must use coincident grids as it is impossible to interpolated integer values Using a dfs2 file If you define your model domain using a dfs2 grid file then you must define the cell values as follows e Grid cells outside of the model domain must be assigned a delete value usually 1e 35 e Grid cells inside the model domain must be assigned a value of 1 e Grid cells on the model boundary must be assigned a value of 2 This distinction between interior grid cells and boundary cells is to facili tate the definition of boundary conditions For example drainage flow can be routed to external boundaries but not to internal boundaries The catchment definition is displayed in the greyed out text boxes but is not editable since the catchment definition is part of the dfs2 file format If you want to change the cell size origin number of cells etc you must change the dfs2 file itself For more information on editing and setting up the Model Domain and Grid see Your Conceptual Geologic Model V 1 p 49 Using a shp file It is much easier to define your Model Domain and Grid via an ArcView shp file i e a grid independent polygon In this case the definition of integer code values is taken care of automatically Further the definition of the grid number of rows and columns cell size and origin can be eas ily adjusted 53 LEA Setup Data Tab 2
302. on between two instantaneous values Related Items e Snowmelt Constants V 2 p 62 e Creating Time Series in MIKE SHE V 1 p 243 e Working with Spatial Time Series VJ p 245 e Time Series Types V p 246 61 a Setup Data Tab 2 9 5 Snowmelt Constants m Snowmelt Constants Degree day factor 2 mm day C Threshold melting temperature 0 pi Degree day factor The degree day factor mm snow day degree C is the amount of snow that melts per day for every degree the Air Temperature V 2 p 60 is above the threshold melting temperature Threshold melting temperature The threshold melting temperature is the temperature at which the snow starts to melt usually OC Distributed snowmelt constants can be specified using the Extra Parame ters section See Distributed Snow Melt Constants VJ p 157 Related Items e Distributed Snow Melt Constants V1 p 157 e Air Temperature V2 p 60 2 10 Land Use NV Paved areas Check water level before routing to river IV Irrigation Requires ET and UZ Priority scheme The Land Use item in the data tree is used to define the items that are on the land surface that affect the hydrology in your model area including e Vegetation distribution e Paved areas Paved Runoff Coefficient V 2 p 68 and e Irrigation 62 MIKE SHE Land Use Se Paved areas The Paved areas option allows you to direct a portion of the overland flow directly to the
303. on modelling in three dimensions Appl Math Modelling Vol 16 pp 506 519 Villholth K 1994 Field and Numerical Investigation of Macropore Flow and Transport Processes Series Paper no 57 Institute of Hydrodynamics and Hydraulic Engineering Technical University of Denmark 230 pp Yan J J and K R Smith 1994 Simulation of Integrated Surface Water and Ground Water Systems Model Formulation Water Resources Bulletin Vol 30 No 5 pp 1 12 References 379 380 MIKE 21 INDEX 381 Se Index Numerics Campbell 174 2 norm reduction criteria 294 Campbell Burdine 176 3D Finite Difference Method 103 289 Canopy BW See ca eg ag end es ee es Ge gs 259 A Canopy Evaporation 245 Actual time step Canopy Interception 244 Elea ae Sots os ats eae 33 Channel Flow 227 OL sn gogn ue hw BP Bea GOK d 33 Classification UZ Save Se eg Ss ose ye des toes ase ee 33 Partial automatic 97 Air Temperature 60 Specified ah oe Fee tw ed 98 Area Inundation Exchange 239 Coefficients Calculation Exchange Flows 239 Evapotranspiration 251 AROOT ice wae ae ae ae 249 Column Classification 91 Average steady state river conductance Computational Layers 116 295 Conductivity a ate ee RS 174 Averjanov 175 Conjugate Gradient 43 Control Parameters B Ol pak ew
304. on will take you to a summary dialogue where you can execute the function by clicking on the Execute button To exit the wizard click on the Finish button which will temporarily save your setup If you click Cancel your setup will not be saved After clicking Finish you must click the Save icon in the top menu bar to permanently save your setup 11 1 Data Analysis 11 1 1 Grid series file compare The Grid series file compare tool is very useful during calibration and for scenario analysis With this tool you can do create a composite grid series file between two dfs2 or dfs3 output files MIKE SHE Editors e 203 LAA MIKE SHE Toolbox After the initial Tool Name dialogue is the calculation setup dialogue Enter parameters for comparing x Reference grid series file fats2 X I ap Scenario grid series file fats2 X aa I Define zones integer codes in dfs2 file E Grid series comparison method Min scenario reference bl Zone output type Multiplier value check to use a dfs file Sum bd 1 Output timeseries file i Ess Sas 11 2 File Converter 11 2 1 dfs2 dfs0 to dfs2 This tool is used to build a time varying dfs2 file from a dfs2 grid code file and one or more dfsO time series files The time varying dfs2 file can be used for time varying gridded data items including Precipitation Rate and Evapotranspiration As with all the Toolbox tools the tool runs silently I
305. onductivities of the two zones were upper zone le 9 m s lower zone le 5 m s For rainfall a synthetic time series with alternating daily values of 50 and 0 mm day was used The simulation period was 2 weeks Thus the cumu lative rainfall input was 350 mm For the case where the overland flow was routed directly to the river the cumulative runoff to the river was 167 mm Whereas when the overland flow was routed first to the lower zone the cumulative runoff reaching the river was only 1 mm Technical Reference for Water Movement 225 a Overland Flow Reference Activating the option This option is activated by means of the boolean Extra Parameter No Simple OL routing set to On For more information on the use of extra parameters see Extra Parameters VJ p 145 226 MIKE SHE Simplified Overland Flow Routing Se 14 CHANNEL FLOW REFERENCE The hydrologic components of MIKE SHE are directly coupled to DHI s river hydraulic program MIKE 11 The MIKE SHE MIKE 11 coupling enables e the one dimensional simulation of river flows and water levels using the fully dynamic Saint Venant equations e the simulation of a wide range of hydraulic control structures such as weirs gates and culverts e area inundation modelling using a simple flood mapping procedure that is based on simulated river water levels and a digital terrain model e dynamic overland flooding flow to and from the MIKE 11
306. onents As outlined above the overland time step is always less than or equal to the UZ time step and the UZ time step is always less than or equal to the SZ time step However the exchanges are only made at a common time step boundary This means that if one of the time steps is changed then all of the time steps must change accordingly To ensure that the time steps always meet the initial ratios in the maximum time steps specified in this dialogue are maintained After a reduction in time step the subsequent time step will be increased by timestep timestep x 1 IncrementRate 2 1 until the maximum allowed time step is reached Relationship to Storing Time Steps The Storing Time Step specified in the Detailed time series output V 2 p 138 dialogue must also match up with maximum time steps Thus The OL storing time step must be an integer multiple of the Max UZ time step The UZ storing time step must be an integer multiple of the Max UZ time step The SZ storing time step must be an integer multiple of the Max SZ time step The SZ Flow storing time step must be an integer multiple of the Max SZ time step and The Hot start storing time step must be an integer multiple of the maximum of all the storing time steps usually the SZ Flow storing time step For example if the Maximum allowed SZ time step is 24 hrs then the SZ Storing Time Step can only be a multiple of 24 hours i e 24 48 72
307. op stress factor The crop stress factor is the minimum allowed frac tion of the crop specific reference ET that the actual ET is allowed to drop to before irrigation starts That is the minimum allowed Actual ET Reference ET x K relationship This should be a value between 1 and 0 If the actual Crop Stress factor falls below the given value irrigation will be added Ponding depth When using this option the demand will be equal to the difference between the actual ponding depth and specified ponding depth The option is typically used for modelling irrigation of paddy rice If the ponding depth falls below the specified value then more irri gation water is added Max allowed deficit The available water for crop transpiration AW is the difference between the actual water content and the water content at the wilting point for the root zone The maximum available water for crop transpiration MAW is then the value of AW for the reference moisture content where either the saturated water content or the field capacity can be specified for the reference moisture content The defi cit can then be defined as the fraction of the MAW that is missing and is a value between 0 and 1 where 0 is the deficit when the actual mois ture content is equal to the reference moisture content and 1 is the def icit when the available water for crop transpiration is zero which is when the water content drops below the water content at the wilting poin
308. or the processed data dia logue plus an uneditable text box displaying the current fif file created by the pre processor Load After you have pre processed your model setup and a fif file is created you can click on the Load button to load the contents of the fif file and view the actual model input data If the model Setup data has been changed since the last pre processing you will get a warning message telling you that the pre processed data may not match the current setup data Note If you have changed anything in your model setup and then run the pre processor again you must re load the new fif file to be able to see the changes in the preprocessed view 146 MIKE SHE Processed Data Pre processed Data View MIKE SHE Flow Model Descrip S Processed data Surface Topography s Model Domain and Gric s Precipitation Stations Evapotranspiration Overland s Manning Number Detention Storage Initial Water Depth sx Overland SZ exch Overland SZ Leak Inundation Area Separated Overlan River Links Unsaturated Zone Saturated Zone meter Manning Number 610000 Sr 600000 ee i a 590000 S feos 580000 570000 4 560000 1960000 1980000 meter Once the pre preprocessed data in the fif file has been loaded then the data tree reflects all the spatial data defined in the model set
309. ormation is interpolated dynamically during the run This is nec essary because the time steps in MIKE SHE can dynamically change dur ing the simulation in response to stresses on the system Related Items e Precipitation V 2 p 57 e Evapotranspiration V 2 p 79 3 1 3 River Links The coupling between MIKE 11 and MIKE SHE is made via river links which are located on the edges that separate adjacent grid cells The river link network is created by the pre processor based on the MIKE 11 cou pling reaches The entire river system is always included in the hydraulic model but MIKE SHE will only exchange water with the coupling reaches The location of each of MIKE SHE river link is determined from the co ordinates of the MIKE 11 river points where the river points include both digitised points and H points on the specified coupling reaches Since the MIKE SHE river links are located on the edges between grid cells the details of the MIKE 11 river geometry can be only partly included in MIKE SHE depending on the MIKE SHE grid size The more refined the MIKE SHE grid the more accurately the river network can be reproduced This also leads to the restriction that each MIKE SHE grid cell can only couple to one coupling reach per river link Thus if for example the dis tance between coupling reaches is smaller than half a grid cell you will probably receive an error as MIKE SHE tries to couple both coupling reaches to the same riv
310. orporated in the weight functions so that the mass transports can be calculated in one step Irregular Grid In general the flow simulation may use varying layer thickness for the ver tical discretisation of the saturated zone domain In this case the code checks each layer to see whether its thickness is identical with the thick Technical Reference for Water Quality 337 LEA Advection Dispersion Reference ness of the layer above and the layer below in each of the grid cells If this is the case this layer is handled as described for regular grid above 3D If this is not the case a different approach is followed where a 2D regular grid solution based on the QUICKEST scheme is used for the horizontal transport and the vertical transport is taken into account as an explicit sink source term 19 2 3 Initial Conditions The initial concentration is a fully distributed concentration field which can be entirely uniform or constant by layer A boundary water flux into the model results in a constant concentration boundary at the initial concentration value unless explicitly specified as a time varying concentration boundary 19 2 4 Source Sinks Boundary Conditions and other Exchanges Boundary conditions for the groundwater transport component can be either e a prescribed concentration Dirichlet s condition or e prescribed flux concentration Neumann s condition Catchment boundary cells with a specified head ar
311. osity must be greater than 0 and less than 1 For unconsolidated porous media the porosity is usually from 0 15 to 0 3 depending of the grain size distribution the more uniform the higher the effective porosity For fractured media the porosity is usually much lower in the from 0 01 to 0 05 Related Items e Solute Transport in the Saturated Zone V 2 p 329 2 16 15 Dispersion Coefficients LHH THH TVH LVV THV Dispersion Coefficients LHH THH TVH LVV THV dialogue Type Stationary Real Data EUM Data Units Dispersion Coefficient If dispersion is included then the two different dispersion options differ in the number of dispersion parameters required If you assume isotropic conditions you need to specify the longitudinal dispersivity and the 115 Setup Data Tab transversal dispersivity a If you assume anisotropic conditions you need to specify five dispersivities The magnitude of the dispersivity coefficient depends on the degree of heterogeneity in your geology and the degree to which these heterogene ities have been described in the model The more heterogeneous your geology is the larger the dispersivities should be On the other hand the more detailed you have described the heterogeneities with your model geometry the smaller dispersivities should be Further the magnitude of the dispersivities depends on the size of the model and on the model grid size The larger the model the larger the
312. ossible to lump the unsaturated zone calculations where the unsaturated flow conditions are identical The unsaturated flow conditions in two cells are identical when they have e identical soil and vegetation characteristics AND e identical boundary conditions If these two conditions are met then the calculations need only be made in one of the cells and the results transferred to the other cell In practical terms the first condition is usually not a serious restriction since most models are divided into several homogeneous soil zones The second condition however is much more restrictive Fluctuations in the groundwater table usually vary from cell to cell and spatial variations in rainfall and the topography cause overland flow and infiltration to vary continuously across the domain Technical Reference for Water Movement 281 Unsaturated Flow Reference However if homogeneous zones can be defined based on e Topography e Meteorology e Vegetation e Soil and e Bypass characteristics then a representative cell for the zone can be defined and used for the UZ calculations If this is done then the boundary conditions from the repre sentative cell i e infiltration rate evapotranspiration loss and groundwa ter recharge can be transferred to the other cells within the zone Such an approximation does not introduce any water balance errors but it can influence the dynamics of the simulation However
313. port Li Ki J i i i Pi 2 i i i i i x Biia z 23 265 A r LF EREA 2 ey Zsjie cy Zypiel rz Zfjie E I SP i feed 3 METE cy 703 oz i 203 faced x gst ey e a ootbeehi ata x erected la rd cr FFY gr yrs ry Br xey goreg fg prs grxey i i i A i i 6 EX iest 1 ry E y ez om 1 3 i i i i 1 i 7 x ae xes ae yes yao yor KEE Eg Be yor KFY i i i 8 Ex oeypes Ey z xE EZ sexry The locations of the weights are determined by the points that enter into the discretisation and because the scheme is upstream centred the weights are positioned relative to the actual direction of the flow 336 MIKE SHE User s Guide Solute Transport in the Saturated Zone ao x TRANSPORT x j Figure 19 4 Location of interpolation weights for determination of concentrations at the location j 14k a grid boundary The dispersive transport can be derived in a similar way With the finite difference formulation of the dispersive transport components based on upstream differencing in concentrations and central differencing in disper sion coefficients the transport in the x direction can be expressed in the following manner TDaju Ye Da n Daina crim cim Ax Y2 Do pis Dozsi cieri Cyr Cikli Cpe i 4dyAx 12 Daji E Drzi cirer cpines Cima Cpi AZAK 19 14 The dispersive transports in the other directions are expressed in a similar way The dispersive transports are inc
314. pressure head is below the pressure head corresponding to the field capacity of the soil then the initial mois ture content is set to the field capacity 16 3 Two Layer Water Balance The Two Layer Water Balance Method is an alternative to the more com plex unsaturated flow process coupled to the Kristensen and Jensen mod Technical Reference for Water Movement 275 Unsaturated Flow Reference ule for describing evapotranspiration The Simplified ET for the Two Layer Water Balance Method is based on a formulation presented in Yan and Smith 1994 The main purpose of the module is to calculate actual evapotranspiration and the amount of water that recharges the saturated zone The module is particularly useful for areas with a shallow ground water table such as swamps or wetlands areas where the actual evapotranspira tion rate is close to the potential rate In areas with deeper and drier unsaturated zones the model does not realistically represent the flow dynamics in the unsaturated zone The model only considers average con ditions and does not account for the relation between unsaturated hydrau lic conductivity and soil moisture content and thereby the ability of the soil to transport water to the roots The model simply assumes that if suffi cient water is available in the root zone the water will be available for evapotranspiration However it may be possible to calibrate the input parameters so that the m
315. quation is usually referred to as Richards equation which is named after L A Richards who first used it in 1931 It still applies when y becomes positive in which case the equation degenerates to the LaPlace equation The sink terms in Eq 16 7 are calculated from the root extraction for the transpiration in the upper part of the unsaturated zone The integral of the root extraction over the entire root zone depth equals the total actual evapotranspiration Direct evaporation from the soil is calculated only for the first node below the ground surface 16 1 1 Numerical Solution MIKE SHE uses a fully implicit formulation in which the space deriva tives of Eq 16 7 are described by their finite difference analogues at time level n 1 The values of C and K are referred to at time level n 4 These are evaluated in an iterative procedure averaging C K with cC K respectively C and K are calculated as a running average of the coefficients found in each iteration Technical Reference for Water Movement 263 Unsaturated Flow Reference This solution technique has been found to eliminate stability and conver gence problems arising from the non linearity of the soil properties For an interior node the implicit scheme yields the following discrete for mulation of the vertical flow ial eu 4741 2 7 J 1 2 B50 16 8 where the subscript J refers to the spatial increment and the superscript n refers
316. r sion in surface water depends on the homogeneity of the velocity distribu tion in the flow cross section To some extent the dispersion depends on the mean flow velocity However there is no general dependence between the dispersion coefficient and the mean flow velocity Therefore in sur face water models the dispersion coefficient is usually specified directly In MIKE SHE the dispersion coefficients are assumed constant in time but may vary in space 344 MIKE SHE User s Guide Solute Transport in Overland Flow LAA 19 4 1 Governing Equations The transport of solutes on the ground surface is governed by the two dimensional advection dispersion equation de a 2 de T EA T a ae cvs t E Dy ERY hats gesah Xi Xi Xj 19 26 where c is the concentration of the solute R is sum of sources and sinks Dj is the dispersion tensor and v is the velocity tensor The velocity of water is determined from the water flux and water depth calculated during the WM simulation For overland transport the longitudinal and transverse dispersion coeffi cients Dz and D are specified directly and the dispersion coefficients applied in Eq 19 26 are determined as for isotropic conditions in groundwater as ye ye Da Du S Di oa t Dr qa ye V5 Dy Dz Dra Din VV Dy De Dr Dz 5 Dr 19 27 The water depth on the ground surface varies in space and time due to variations in topography as well as variation
317. r all soil types which characterise the individual soil profiles within the model area e the Soil Moisture Retention Curve and e the Hydraulic Conductivity Function This information along with the following parameters is stored in the soil property database e soil moisture at saturation 0 e soil moisture at effective saturation 0 e capillary pressure at field capacity pF e capillary pressure at wilting point pF e residual soil moisture content 0 e saturated hydraulic conductivity K pF is defined as log10 100y where y is the matric potential Notice that y is always negative under unsaturated conditions The soil moisture at effective saturation 0 is the maximum achievable soil moisture content 6 1 Soil Moisture Retention Curve The relationship between the water content 0 and the matric potential y is known as the soil moisture retention curve which is basically defined by the texture and structure of the soil The amount and type of organic material may also have an influence on the relationship Characteristically the pressure head decreases rapidly as the moisture content decreases Hysteresis is also common that is the relationship between 0 and y is not unique but depends on whether the moisture content is increasing or decreasing MIKE SHE allows for any shape of the soil moisture retention curve but does not take hysteresis into account i e a unique relation between 0 and y
318. r example if your MIKE 11 river network does not extend into the subcatchment you can specify that the interflow discharges to a particular node or set of nodes in a nearby river net work If you uncheck this checkbox a sub item will appear where you can specify the river branch and chainage to link the subcatchment to 54 MIKE SHE Subcatchments a The river links for the baseflow zones are specified separately in the baseflow zone dialogues Related Items e Simplified Overland Flow Routing V 2 p 220 e Overland Flow Zones V 2 p 87 e Linear Reservoir Method V 2 p 307 e Interflow Reservoirs V 2 p 105 2 7 1 River Links Branch name Upstream Speed River If you have unselected the Use default river links option in the Subcatch ments dialogue or in the Baseflow Reservoirs dialogue then this dialogue will be added to the data tree In this dialogue you can specify the branch name to connect a subcatchment to as well as the upstream and down stream chainage of the branch This dialogue is not intelligent in the sense that it does not read the MIKE 11 river network file You must type the branch name exactly as it appears in the river network file and specify valid chainages If either the name or the chainages are invalid then you will get an error during the model pre processing stage Related Items e Coupling MIKE 11 and MIKE SHE VJ p 165 55 LEA Setup Data Tab 2 8 Topography
319. r quality for 10 years To do this you would specify the start and stop dates of the part of the water move ment simulation that you want repeated If you want to repeat the whole water movement simulation then you would specify the begin ning and end of the water movement simulation Constant water movement flow field In this case the nearest saved time step to this date will be used as a steady state flow field for the transient water quality simulation 48 MIKE SHE Water Quality Simulation Specification 2 3 3 Water Quality Time Step Control Max Simulation timestep Saturated Zone SZ Unsaturated Zone UZ Overland OL ficoo00000 hrs Max Advective Courant Number jas fo 8 jas H Max Dispersive Courant Number jas 0 5 jas H Max Transport Limit Water Quality Time Step Control Conditions if the Include Advection Dispersion AD Water Quality option selected in the Simulation Specification dialogue The water quality simulation is completely decoupled from the water movement simulation and like the water movement itself the water qual ity time steps can be different in each of the overland flow unsaturated flow and saturated flow Maximum Simulation Time Step This is the maximum user specified time step allowed The default value is very high so that the simulation runs by default with the highest possible time step You might want to set this value to a short time interval if you w
320. ranch Gaps of this type are not important to the calculation of the exchange flows between the hydrologic components e g overland to river or SZ to river The exchange flows depend on the water level in the MIKE 11 river which is unaffected by gaps in the coupling reaches However MIKE SHE can calculate how much of the water in the river is from the various hydrologic sources e g fraction from overland flow and SZ exfiltration However this sort of calculation is only possible if the MIKE SHE branch is continuous If there is a gap in a MIKE SHE branch then the calculated contributions from the different hydrologic sources downstream of the gap will be incorrect If there are gaps in the MIKE SHE branch network then the correct contributions from the different sources must be determined from the MIKE 11 output directly Furthermore the MIKE 11 MIKE SHE coupling for the water quality AD module will not work correctly in there are gaps in the MIKE SHE branch network There is one further limitation in MIKE SHE That is no coupling branch can be located entirely within one grid cell This limitation is to prevent multiple coupling branches being located within a single grid cell Connections Between Tributaries and the Main Branch Likewise the connections between the tributaries and the main branch are only important for correctly calculating the downstream hydrologic con tributions to the river flow and in the advection dispers
321. ration from SZ 11 __ overland flow in x direction overland flow in y direction indiltendiar DA j 17 franetivea Filename C5 TestingINRSaby NrSeby2003 7layer 250biNrSaby 200 C 5 Testing NRSaby NrSaby2003 7layer 250b NrSaby200 CA5 Testing NRSaby NrSaby2003 7layer 250biNrSaby200 C15 Testing NRSabyNrSaby2003 Tlayer 250b NrSaby200 C 5 Testing NRSabyNrSaby2003 7layer 250biNrSaby200 C 5 Testing NRSabyNrSaby2003 7layer 250biNrSaby200 C 15 Testing NRSaby NrSaby2003 7layer 250b INrSaby200 C A5 Testing NRSaby NrSaby2003 7layer 250b NrSaby200 C 15 Testing NRSaby NrSaby2003 7layer 250b NrSaby200 C 15 Testing NRSaby NrSaby2003 7layer 250b NrSaby200 fonts Testing NRSabyNrSaby2003 7layer 250biNrSaby200 fons Testing NRSabyNrSaby2003 7layer 250biNrSaby200 o rr TaestinathIDCahuihlyCahoINN Tavar IAN Cahu annn View result View result View result View result View result View result View result View result View result View result Aimas vama ib IWMI This table is a list of all gridded data saved during a MIKE SHE simula tion The items in the list originate from the list of items selected in the Grid series output V 2 p 143 dialogue from the Setup tab View Result Clicking on the View result button will open the Results Viewer to the current item All overlays from MIKE SHE e g shape files images and grid files will be transferred as overlays to the result
322. re 0 is the saturated water content 0 is the water content at the end of the previous time step and z is the depth of the water table The actual infiltration to the unsaturated zone Infactuap 18 then calculated as the minimum of the amount of ponded water before infiltration the rate limited amount of infiltration or the maximum volume of infiltration Thus Infrcimal min d nf lnf Subsequently d and O are updated doc doc lact mm Oact Pact Taca 1000 where refers to the parameter value before updating 15 2 5 Evapotranspiration Actual evapotranspiration is calculated from the reference evapotranspira tion rate E The reference rate is typically described as a time series 258 MIKE SHE Simplified ET for the Two Layer Water Balance Method a oe which may be derived from pan measurements or calculated using for example the Penman Monteith equations The reference ET is satisfied in the following order 1 Evaporation is first deducted from the interception storage assuming the potential ET rate 2 If the interception storage cannot satisfy the potential ET water is evaporated from the ponded water doc until the ponded water is exhausted or the potential ET is satisfied 3 If the potential ET has not yet been satisfied water is ET is removed from the unsaturated zone until the potential ET is satisfied or the water content of the upper ET layer is reduced to Onin If t
323. re cells potentially have a higher infiltration capacity To avoid this redistribution an option has been added where the solver only calcu lates overland flow for the cells that can potentially produce runoff that is only in the cells for which the water depth exceeds the detention storage depth Example application To illustrate the effect of this option it was applied to a model with a 10 x 10 square domain one subcatchment and 3 different soil types in the unsaturated zone with the following saturated hydraulic conductivities coarsele 5 m s medium le 7 m s fine le 9 m s For rainfall a synthetic time series with alternating daily values of 50 and 0 mm day was used The simulation period was 2 weeks Thus the cumu lative rainfall input was 350 mm For the case where the ponding water was not redistributed the cumula tive runoff was 96 mm Whereas when the ponded water was redistrib uted the cumulative runoff was essentially zero 224 MIKE SHE Simplified Overland Flow Routing LEA Activating the option This option is activated by means of the boolean Extra Parameter Only Simple OL from ponded set to On For more information on the use of extra parameters see Extra Parameters V 1 p 145 13 2 5 Routing simple overland flow directly to the river In the standard version of the Simplified Overland Flow solver the water is routed from higher zones to lower zones within a subcatchment Thu
324. removed from the Baseflow Res ervoirs via groundwater pumping Qpump If UZ feedback is included then some of the baseflow to the stream will be added to the UZ storage Quz and subsequently removed from the unsaturated zone via ET In some situations the interflow reservoirs will not correspond to the areas of active baseflow in the current catchment That is some percolation from the interflow reservoirs may contribute to baseflow in a neighbour ing watershed This has been resolved by introducing a dead zone storage Queaa between the Interflow and Baseflow Reservoirs 17 2 4 Calculation of Interflow Each Interflow Reservoir is treated as A Single Linear Reservoir with Two Outlets p 309 Thus from Eq 17 30 if the water level in the linear res ervoir is above the threshold water level qr h Nthresni k 17 37 Technical Reference for Water Movement 313 Saturated Flow Reference where q is the specific interflow i e Q A from Eq 17 30 h is the depth of water in the interflow reservoir hjy es is the depth of water required before interflow occurs and k is the time constant for flow If the water level is below the threshold there is no interflow Similarly if there is water in the linear reservoir specific percolation out flow can be calculated from apere Wk 17 38 where A is again the depth of water in the interflow reservoir and k is the time constant for percolation flow If the water
325. rence between a grid cell and the river is calculated as Ah hrig h i 14 2 where Agria is the head in the grid cell and is the head in the river link as interpolated from the MIKE 11 H points If the ground water level drops below the river bed elevation the head dif ference is calculated as Ah Zo h 14 3 riv where Zpor is the bottom of the simplified river link cross section which is equal to the lowest point in the MIKE 11 cross section In Eq 14 1 the conductance C between the cell and the river link can depend on e the conductivity of the aquifer material only See Aquifer Only Con ductance V 2 p 234 or e the conductivity of the river bed material only See River bed only con ductance V 2 p 235 or e the conductivity of both the river bed and the aquifer material See Both aquifer and river bed conductance V 2 p 237 14 2 1 Aquifer Only Conductance When the river is in full contact with the aquifer material it is assumed that there is no low permeable lining of the river bed The only head loss 234 MIKE SHE River Aquifer Exchange line source link a oe between the river and the grid node is that created by the flow from the grid node to the river itself This is typical of gaining streams or streams that are fast moving Thus referring to Figure 14 2 the conductance C between the grid node and the river link is given by _ K da dx C ds 14 4 where
326. resolution varies slowly the error introduced is small 19 3 3 Initial Conditions The initial concentration in the unsaturated zone is given as average con centrations The unit for the concentration is mass volume This way of giving the initial conditions has the advantage that you does not have to worry about the vertical discretisation and the water content On the other hand you do not know the exact amount of mass introduced into the unsaturated zone since this depends on the initial water content deter mined in the water movement simulation 19 3 4 Source Sinks Boundary Conditions and other Exchanges Sources for solute input into the unsaturated zone can be given in a number of ways both as point or line sources at specific depth intervals or as area sources at specific locations Dissolved matter can enter the unsaturated zone in three different ways It can either be added to the precipitation as a so called precipitation source if the overland part is not included in the simulation or it can be a UZ Technical Reference for Water Quality 343 Advection Dispersion Reference source introduced at a certain depth or it can enter from the saturated zone The precipitation source option is described in the section about Overland Solute Transport The unsaturated zone transport component exchanges mass with the over land and the groundwater transport components as indicated in Figure 2 The transport from the overla
327. rotection Agency Copenhagen Plauborg F and J E Olesen 1991 Development and validation of the model MARKVAND for irrigation scheduling in agriculture Tidsskrift for Planteavls Specialserie Beretning S 2113 Danish Institute of Plant and Soil Science Foulum Denmark In Danish Refsgaard A Refsgaard J C Clausen T 1993 A three dimen sional module for groundwater flow and solute transport in SHE Danish Hydraulic Institut Internal Note Refsgaard J C and J Knudsen 1996 Operational validation and intercomparison of different types of hy7drological models Water Resources Research 32 7 pp2189 2202 Refsgaard J C T H Christensen and H C Ammentorp 1991 A Model for oxygen transport and consumption in the unsaturated zone Journal of Hydrology 129 349 369 Scheidegger A E 1961 General theory of dispersion in porous media Jour of Geophys Research Vol 66 no 10 Thomas R G 1973 Groundwater models Irrigation and drainage 378 MIKE 21 Se 35 36 37 38 Spec Pap Food Agricultural Organis No 21 U N Rome Toride N FJ Leij and M Th van Genuchten 1995 The CXT FIT code for estimating transport parameters from laboratory or field tracer experiments Version 2 0 Research report No 137 U S Salinity Lab oratory Agricultural Research Service USDA River side California Vested H J Justesen P and Ekebjzerg L 1992 Advection dis persi
328. routed but removed from model 123 LEA Setup Data Tab Saturated zone drainage is a special boundary condition in MIKE SHE used to defined natural and artificial drainage systems that cannot be defined in the MIKE 11 River setup It can also be used to simulate over land flow in a simple lumped conceptual approach Surface drainage can only be applied to the top layer of the Saturated Zone model Water that is removed from the saturated zone by surface drainage is routed to local surface water bodies Drainage flow is simulated using an empirical formula which requires for each cell a drainage level and a time constant leakage factor that are used for routing the water our of the element Both drain levels and time constants can be spatially defined A typical drainage level is 1m below the ground surface and a typical time constant is between 1e 6 and 1e 7 1 s MIKE SHE also requires a reference system for linking the drainage to a recipient cell which can be a MIKE 11 river node another SZ grid cell or a model boundary Whenever drain flow is produced during a simulation the computed drain flow is routed to the recipient point using a linear res ervoir routing technique There are three different options for setting up the reference system for drainage Drainage routed downhill based on adjacent drain levels This option was originally the only option in MIKE SHE The reference system is created automatically us
329. rs 0 00000 00000 ene 165 8 MIKE Zero WELLE EDITOR ace tod te ke tad ao ee oe Bem ER eek en ee 167 5 0 1 Interactive Map o4 4i00 24 word dare i oe ea Reh od 167 5 0 2 WellLoc ti s sseeg ae oath y arg ty epee Ped e Bie k 168 5 0 3 Well Filters 2 2 0 5 dae oe Gice Baek Se Be eee A ee aS 169 504 Layers Display lt enrag ee dda eueiedeoseees 170 5 1 Importing Data 2 n2 a ede Pew Bee Bom amp Bw eae 170 5 1 1 Importing datafroma t0file 171 5 1 2 Importing TAB delimited textfile 172 UZ SOIL PROPERTIES EDITOR lt 2 co 5c 2s ee dad dance nek ue Rae 173 6 1 Soil Moisture Retention Curve 2 2 2000 173 6 1 1 Tabulated 2 0 000000000004 174 6 1 2 Van Genuchten and Campbell Functions 174 6 2 Hydraulic Conductivity Function 2 174 6 2 1 Tauber 222 had tee ee ete eRe at eee eee 175 6 2 2 Averjanov 20 5 Sot aoa bP eek Paes a 175 6 2 3 Van Genuchten and Campbell Burdine methods 176 ET VEGETATION PROPERTIES EDITOR 177 7 1 Vegetation Database Items 00 04 4 177 7 1 1 Specifying Vegetation Properties ina Database 177 7 1 2 Vegetation stages sc cio bi eee SbDE DDE ee eee 178 7 1 3 Evapotranspiration Parameters 179 7 1 4 Vegetation Development Table 180 7 1 5 Irrigation Parameters aana aaa aaa ee ee amp 181 7
330. rvoir with the next lower grid code number until the reservoir with the lowest grid code number within the subcatchment is reached The reservoir with the lowest grid code number will then drain to the river links located in the reservoir If no river links are found in the reservoir then the water will not drain to the river and a warning will be written to the run log file For example in Figure 17 9 Interflow Reservoir 2 always flows into Reservoir 1 and Res ervoir 1 discharges to the stream network Likewise Reservoir 5 flows into 3 which discharges to the stream network For baseflow the model area is subdivided into one or more Baseflow Reservoirs which are not interconnected However each Baseflow Reser voir is further subdivided into two parallel reservoirs The parallel reser voirs can be used to differentiate between fast and slow components of baseflow discharge and storage Figure 17 10 is a schematization of the flow to from and within the sys tem of linear reservoirs Vertical infiltration from the unsaturated zone is distributed to the Interflow Reservoirs Qin Water flows between the Interflow Reservoirs sequentially Qz and eventually discharges directly to the river network QJ river or percolates vertically to the deeper Base flow Reservoirs Qperc The parallel Baseflow Reservoirs each receive a fraction of the percolation water Q and each discharges directly to the river network Qp Groundwater can be
331. ry Real Data EUM Data Units HydrConductivity The hydraulic conductivity is a function of the soil texture and is related to the ease with which water can flow through the soil Loose coarse uni form soils have a higher conductivity than compacted soils with a range of particle sizes Thus a loose uniform coarse sand can have a horizontal hydraulic conductivity as high as 0 001 m s Whereas a tight compacted clay can have a have a horizontal hydraulic conductivity as low as 1x10 8 m s which is 5 orders of magnitude 112 MIKE SHE Saturated Zone Ss The horizontal hydraulic conductivity is typically 5 to 10 times higher than the vertical hydraulic conductivity MIKE SHE assumes that the horizontal conductivity is isotropic in the x and y directions Related Items e Geological Units V2 p 108 e Vertical Hydraulic Conductivity V 2 p 113 e Working with Lenses VJ p 52 2 16 11 Vertical Hydraulic Conductivity Vertical Hydraulic Conductivity dialogue Type Stationary Real Data EUM Data Units HydrConductivity The hydraulic conductivity is a function of the soil texture and is related to the ease with which water can flow through the soil Loose coarse uni form soils have a higher conductivity than compacted soils with a range of particle sizes Thus a loose uniform coarse sand can have a horizontal hydraulic conductivity as high as 0 001 m s Whereas a tight compacted clay can have a have a hor
332. s overland flow generated in the upper zone is routed to the next lowest flow zone based on the integer code values of the two zones In other words at the beginning of the time step the overland flow leaving the upper zone calculated in the previous time step is distributed evenly across all of the cells in the receiving zone In practice this results in a dis tribution of water from cells in the upstream zone with ponded water e g due to high rainfall or low infiltration to all of the cells in the downstream zone with potentially a large number of those cells having a higher infil tration capacity In this case then overland flow generated in the upper flow zone may never reach the stream network because it is distributed thinly across the entire downstream zone To avoid excess infiltration or evaporation in the downstream zone an option was added that allows you to route overland flow directly to the stream network In this case overland flow generated in any of the over land flow zones is not distributed across the downstream zone but rather it is added directly to the MIKE 11 stream network as lateral inflow Example application To illustrate the effect of this option it was applied to a model with a 10 x 10 square domain one subcatchment and two overland flow zones The upper zone included an unsaturated zone with a low infiltration capacity whereas the lower zone had a high infiltration capacity The saturated hydraulic c
333. s The GUI automatically located the result file based on the input files The check box Import overlays from she file should be checked on if all the overlays from the she files is to be imported into the MODPATH for MIKE SHE setup 9 4 Simulation Tab The Simulation tab is used to define the various particle tracking simula tions that you want to run on the specified WM flow results 9 4 1 Transport Simulations Run Selected B LOKI ALS You can run any number of particle tracking simulations on the flow model results This allows you to set up standard particle tracking simula tions and then run several water movement scenarios Simulation Name An identifying name for the particle tracking simula tion Engine In the current version MODPATH is the only available engine MIKE SHE s particle tracking PT module will be added here in a later version Comment Supplementary information on the particle tracking simula tion Run and Run Selected the Run Selected button will run all of the parti cle tracking simulations that have a check in the Run checkbox MIKE SHE Editors 197 oa Particle Tracking Editor 9 4 2 MODPATH simulation specification Start fio o2 1981 End orozise3 10 57 16 Storing Frequency fos sis Sink strength for t S m Pathline direction Forward C Backward For each MODPATH simulation defined in the Transport Simulations dia logue the contro
334. s above 1 may therefore be relevant for some crops in the mid season during the period where crop leaf area index is at its maximum A Ke value of 1 means that the maximum evapotranspiration rate will equal the reference evapotranspiration rate If pan evaporation data are used in place of reference evapotranspiration data in the model input it often necessary to apply site specific pan coeffi cients to convert the pan evaporation to reference evapotranspiration Pan coefficients are normally in the range 0 5 0 85 7 1 5 Irrigation Parameters In the irrigation module the amount of irrigation applied can be driven by the amount of water demanded by the crop That is in drier periods more irrigation water is required so more irrigation is applied In the Irrigation demand dialogue if you specify that the Vegetation Prop erty file should be used for the demand calculations then the demand val ues will be read from the vegetation file specified in the Vegetation V 2 p 64 dialogue Further in the irrigation module you specify the type of demand calcula tion e User specified e Maximum allowed deficit e Crop stress factor e Ponding depth MIKE SHE Editors e 181 ao ET Vegetation Properties Editor In the Irrigation dialogue of the Vegetation properties file 4 Field Capacity 0 0 0 0 Field Capacity 0 a 0 3 3 0 Field Capacity 0 0 D 4 20 01 0 Field Capacity 0 0 0 is 25 01 0 Field Capacity 0 0 0 e 2
335. s and engines selected for the MIKE SHE simulation The sheres file is a catalogue of all the various output files generated by the current MIKE SHE run When you select the sheres file you are not specifying the particular output but actually just a set of pointers to all the output files The extraction process reads all of the output files and makes itself ready to produce specific water balances In the extraction dialogue you specify the sheres file for the simulation that you wish to calculate the water bal ance for The sheres file is located in the same directory as your results Note Although this is an ASCII file you should be careful not to make any changes in the file or you may have to re run your simulation Type of Extraction You can choose to calculate the water balance on the entire model domain or in just a part of the domain By default the calculation is for the entire domain or catchment If you choose the subcatchment area type they you will be able to use a dfs2 integer grid code file to define the areas that you want individual water balances for 186 MIKE SHE Postprocessings LA If you use an area resolution then the water balance will be a summary water balance for either the entire catchment or the sub areas that you define If you use a single cell resolution you will be able to generate dfs2 maps of the water balance Sub catchment grid codes The subcatchment integer grid code fil
336. s are displayed in front of or behind the current grid which in turn controls the way the colours etc are displayed The best way to understand the way the overlays are displayed is to sim ply play around with a model and some maps to see how the display changes when the map is placed in the foreground vs background or the order is changed The available map types includes ESRI shape shp files Grid dfs2 files Image bmp gif and jpg files MIKE 11 river nwk11 files and MIKE SHE well database wel files 21 a Setup Data Tab 2 1 2 Image Overlays IV Display Image File C 45 Testing NASaby lmages MidtFynl BMP co m Area Coordinates x y Min coords 575845 9912 m 6117918 976 m i 7 i fom fa mport geo reference from file Max coords 6008679912 m 61 38782 001 m m Image Styles Display style Blend colors v Transparent color C If you want to display a background image in your map view then you should add an Image overlay The available image formats include bmp gif and jpg Area Coordinates Since image files do not contain geographic informa tion you must specify the spatial location of the image This is done by specifying the map coordinates of the lower left corner of the image Minimum X and Y and the upper right corner of the image Maxi mum X and Y Import geo reference from file Some DHI programs allow you to geo refer
337. s have been introduced with respect to dispersivity 330 MIKE SHE User s Guide Solute Transport in the Saturated Zone LAA e isotropy and e anisotropy with axial symmetry around the z axis These simplifications are reflected in the number of non zero dispersivi ties to be specified Under isotropic conditions the dispersivity tensor Gijmn Solely depends on the longitudinal dispersivity az and the transver sal dispersivity an in the following manner ce A Aiino ctr Fy Oun a F Sm Sn Gin Sin 19 6 where 6 is the Kronecker delta with 0 for i j and dij 1 for i j In the Cartesian co ordinate system applied in MIKE SHE the velocity compo nents in the coordinate directions are denoted V V and V Thus we obtain the following expressions for the dispersion coefficients Da lerlvi r3t a2 U Dy lalvitr a yu De lar y2 72 anv U Dy az ar Vy fl Dyw Da r amp rWV U Dax D lar ar V U Dy 19 7 This is the general equation for the dispersion coefficients in an isotropic medium for an arbitrary mean flow direction If the mean flow direction coincides with one of the axis of the Cartesian coordinate system the expression for the dispersion coefficients simplifies even further e g if V and V are equal to zero then D Dz and Dy will also be zero Under fully anisotropic conditions the dispersion coefficients depends on 36 dispersivities which is impractical to handle and estim
338. s in precipitation evapora tion infiltration etc Since evaporation can concentrate a solute beyond its solubility a mass balance of precipitated solute is maintained where the solute will re dissolve if additional water becomes available The precipi tation and dissolution of the solute is controlled by its solubility 19 4 2 Solution scheme The solution scheme applied for overland transport uses the same QUICKEST scheme as in the saturated zone It is a fully explicit scheme that using upstream differencing Technical Reference for Water Quality 345 Advection Dispersion Reference Neglecting the dispersion terms and the source sink term and assuming that the flow field satisfies the equation of continuity and varies uniformly within a grid cell the advection dispersion equation can be written as ec a ae vee fbe 0 19 28 and when written in finite difference form becomes che 7 Chk oO ehnat 3 cha was Oy one z cien 0 19 29 where n denotes the time index In Eq 19 29 and o are the directional Courant numbers defined by Vr At _ vy Ag cae Ax Ay Oy Ta 19 30 and the c terms are the concentrations at the surface of the control vol ume at time n As these terms are not located at nodal points they are interpolated from known concentration values by paes Cite r AiCi Cik T ME Bei 19 31 The concentration c is the concentration around the actual point for e
339. ses you must supply a table of intervals upon which the classifi cation will be based The number of computational columns depends on how narrow the intervals are specified If for example two depths are specified say 1 m and 2 m then the classification with respect to the depth to groundwater will be based on three intervals Groundwater between 0 m and 1 m between 1 m and 2 m and deeper than 2 m Related Items e Unsaturated Flow Reference V 2 p 261 e Lumped UZ Calculations V 2 p 281 96 MIKE SHE Unsaturated Zone LEA 2 14 3 Ground Water Table Groundwater Table Conditions if Specified water table for classification selected in the Groundwater Depths used for UZ Classification dia logue dialogue Type Stationary Real Data EUM Data Units Elevation or Height above ground If the Specified water table for classification is selected in the Groundwa ter Depths used for UZ Classification dialogue then this is the ground water table used for the classification Related Items e Unsaturated Flow Reference V 2 p 261 e Lumped UZ Calculations V 2 p 281 2 14 4 Partial automatic classification Partial Automatic Classification Conditions if the Partially automatic column classifications selected in the main Unsaturated Zone dialogue dialogue Type Integer Grid Codes EUM Data Units Grid Code Valid Values lor2 A combination of the Automatic classification and the Specified classifi
340. so transfer particles internally in SZ If this occurs the particles are moved from one compartment to another by the drain Note that there is no time lag in this process To trace the particles calculate transport times capture zones groundwa ter age etc each particle is associated with a particle identification model time and location at which the particle was introduced in the model time and co ordinates of birth When particles enter sinks or are introduced into the model domain by a source this information is registered together with the source sink type and the registration time and location before removing or adding the particle This registration process is also used for keeping track of particles that enter registration cells To avoid repeated registration of particles that have entered a registration cell and which are not immediately removed by a sink in the compartment the particle only registers the first time it enters a registration cell 373 on Particle Tracking Reference 374 MIKE SHE User s Guide REFERENCES 375 1 2 3 4 5 6 T 8 9 10 11 Abbott M B Bathurst J C Cunge J A O Connell P E and Ras mussen J 1986 An introduction to the European Hydrological System Syst me Hydrologique Europ en SHE 2 Structure of a physically based distributed modelling system J Hydrol 87 61 77 Abbott M B and Cun
341. ssigned to a dfsO time series file or assigned to a time varying dfs2 file The last option is typically from a results file It could be from a regional results file which can be extracted using the MIKE Zero Toolbox Extraction tool 2D Grid from 3D files Or it could be from a previous run of the same model Note This boundary condition was previously called the Head control led abstraction boundary condition in early versions of MIKE SHE Head Controlled Flux GHB The head controlled flux or General Internal Head Boundary is similar to the fixed head However a flow resistance is incorporated via a user specified leakage coefficient The head can be a prescribed value assigned to a dfsO time series file or assigned to a time varying dfs2 file The last option is typically from a results file It could be from a regional results file which can be extracted using the MIKE Zero Toolbox Extraction tool 2D Grid from 3D files Or it could be from a previous run of the same model If the GHB is selected an extra item is added to the data tree below the boundary condition for the leakage coefficient The leakage coefficient can be specified as either a simple leakage coefficient 1 time or as a total conductance length time Note This boundary condition was previously called the General Internal Head Boundary condition in early versions of MIKE SHE Inactive Cells This boundary condition is used to make interior cells of th
342. t When using the Max Allowed Deficit method irrigation is started when the deficit exceeds the moisture deficit start value and stops at the moisture deficit end value If for example the reference moisture content is the field capacity and irrigation should start when 60 of the maximum available water in the root zone is used and cease when field capacity is reached again the value for the Start should be 0 6 and the value for the Stop value should be 0 Reference Moisture Content If the Maximum allowed deficit is used then the reference moisture con tent can be either for calculating the deficit is either the saturated water content or the field capacity water content 77 Setup Data Tab Temporal Distribution In each of the demand types the demand factor can be specified as a con stant value or as a time series However an additional option in this com bobox is to use the Vegetation Properties file To use this option you must include a vegetation properties file when you specify the vegetation Fur ther you must specify the irrigation properties in the vegetation properties file itself In this case the Vegetation properties file will contain all of the values needed by each of the different methods and the demand values cannot be input in this dialogue 2 10 6 Irrigation Priorities Irrigation Priorities Conditions Irrigation selected in Land Use and UZ and ET simu lated and Priorities option selecte
343. t the graphic will be displayed by the program WblChart Related items e Using the Water Balance Tool V 1 p 123 MIKE SHE Editors 191 Water Balance Editor 192 MIKE SHE Results Se 9 PARTICLE TRACKING EDITOR MODPATH is a particle tracking program developed to work with the U S Geological Survey s MODFLOW code for groundwater modelling MODPATH has been added to MIKE SHE as an alternative to the particle tracking PT module in MIKE SHE MIKE SHE s PT module is based on the random walk method and is useful for determining dynamic well and well field capture zones by tracking a large number of particles over time However the PT module can be time consuming because it is often track ing hundreds or even many thousands of particles MODPATH on the other hand is very quick as it calculates discrete path lines for individual particles MODPATH is useful for path line and flow analysis in steady state flow fields In addition to computing particle paths MODPATH keeps track of the time of travel for particles moving through the system By carefully defining the starting locations of parti cles it is possible to perform a wide range of analyses such as delineating capture and recharge areas or drawing flow nets The version of MODPATH used in MIKE SHE is based on MODPATH Version 3 downloaded directly from the USGS web site At the moment only steady state MIKE SHE SZ flow fields are sup ported In
344. t the end of the previous time step and z is the depth of the water table The actual infiltration to the unsaturated zone Infocinqi is then calculated as the minimum of the amount of ponded water before infiltration the rate limited amount of infiltration or the maximum volume of infiltration Thus Inf ema min d Anf lnf Subsequently doc and qact are updated doc doc Lace mm Qact Gact Tac Za 1000 where refers to the parameter value before updating Technical Reference for Water Movement 279 LAA Unsaturated Flow Reference 16 4 Simplified Macropore Flow bypass flow Flow through macropores in unsaturated soil is important for many soil types In the Unsaturated Zone module a simple empirical function is used to describe this process The infiltration water is divided into one part that flows through the soil matrix and another part which is routed directly to the groundwater table bypass flow The bypass flow is calculated as a fraction of the net rainfall for each UZ time step The actual bypass fraction is a function of a user specified max imum fraction and the actual water content of the unsaturated zone assuming that macropore flow occurs primarily in wet conditions Thus the bypass flow Q pass 18 calculated as Qbypass Pret Prac OL 1oB50 At 16 28 where P is the net rainfall rate and P is the maximum fraction of the net rainfall which can bypass the m
345. tail on the types of available water balances data are discussed in the Standard Water Balance Types V 1 p 138 section In brief the availa ble types include e The total water balance of the entire model catchment or sub catch ments in an ASCII table a dfs0 file a dfs2 map file or a graphical chart also by layer e Model errors for each hydrologic component overland unsaturated zone etc in an ASCII table a dfs0 file or a dfs2 map file also by layer e The snow melt and canopy interception water balance in an ASCII table or a dfs0 file e An abbreviated or detailed water balance for overland or unsaturated flow in an ASCII table or a dfs0O file and e An abbreviated or detailed water balance by layer for saturated flow in an ASCII table or a dfsO file MIKE SHE Editors 189 Water Balance Editor 8 3 Results Output Period An output period different from the total simulation period can be speci fied by unchecking Use default period and setting the Start date and End date to the period of interest Output time series Specification Incremental or Accumulated water balances can be calculated An incre mental water balance is calculated summed for each output time step in the Output period An accumulated water balance each output time step is accumulated over the Output period Layer Output Specifications If you are using water balance types that calculate data on a layer basis you can spe
346. te Solver The PCG Steady State Solver is virtually identical to the transient PCG solver but has been implemented separately to enhance efficiency In par ticular experience has shown that different solver settings may be required when solving the system in steady state versus a transient solu tion Furthermore since the solvers have been implemented separately there are a couple of options in the steady state solver that are not availa ble in the transient solver Canyon exchange option The Canyon exchange option is only available in the steady state PCG solver It can be used to describe the exchange between a groundwater 294 MIKE SHE 3D Finite Difference Method LAA aquifer and a river when the river cuts deeply into the aquifer e g through a narrow valley If the river water level is below the bottom of the adja cent computational groundwater layer the potential head gradient is reduced In this case the head difference in layers above the river level is limited by the bottom elevation of the layer Thus Ah h max h Z 17 14 where h is the head in the adjacent groundwater node h is the head in the river and z is the bottom of the current layer Without the Canyon option MIKE SHE effectively assumes that the river is hydraulically connected to the upper most model layer since MIKE SHE calculates the exchange flow with all layers that intersect the river based on the difference between the
347. th The water flow on the ground surface is calculated by MIKE SHE s Over land Flow Module using the diffusive wave approximation of the Saint Venant equations or using a semi distributed approach based on the Man nings equation This chapter is the technical reference for the Overland Flow Module in MIKE SHE 13 1 Finite Difference Method 13 1 1 Diffusive Wave Approximation Using rectangular Cartesian x y coordinates in the horizontal plane let the ground surface level be z x y the flow depth above the ground sur face be h x y and the flow velocities in the x and y directions be u x y and v x y respectively Let i x y be the net input into overland flow net rainfall less infiltration Then the conservation of mass gives oh a oe ay 1 13 1 and the momentum equation gives Oh udu lou qu Bie a Ot HO BOE ay 13 2 fx Ox Ox gdx g t gh vn Oh vov 10v qv E oe 13 2b P O Ody g y g t gh l l where Spis the friction slopes in the x and y directions and Sis the slope of the ground surface Equations 13 1 13 2a and 13 2b are known as the St Venant equations and when solved yield a fully dynamic descrip tion of shallow two dimensional free surface flow Technical Reference for Water Movement 211 Overland Flow Reference The dynamic solution of the two dimensional St Venant equations is numerically challenging Therefore it is common to reduce the complex ity of the proble
348. the groundwater elevations In both cases you must supply a table of inter vals upon which the classification will be based The number of com putational columns depends on how narrow the intervals are specified If for example two depths are specified say 1 m and 2 m then the classification with respect to the depth to groundwater will be based on three intervals Groundwater between 0 m and 1 m between 1 m and 2 m and deeper than 2 m If the Linear Reservoir method is used for the groundwater then the Interflow reservoirs are also used in the classification However since feedback to the UZ only occurs in the lowest Interflow reservoir of each subcatchment the Interflow reservoirs are added to the Automatic Classification in two zones those that receive feedback and those that don t e Specified classification Alternatively a data file specifying Integer Grid Codes where UZ computations are carried out can be specified with grid codes range from 2 up to the number of UZ columns see Specified classification The location of the computational column is specified by a negative code and the simulation results are then trans ferred to all grids with the an equivalent positive code 91 Se Setup Data Tab Calculated in all Grid points For smaller scale studies or studies where the classification system becomes intractable you can specify that computations are to be carried out in all soil columns Partial Automati
349. the canopy e Drainage from the canopy to the soil surface e Evaporation from the canopy surface e Evaporation from the soil surface and e Uptake of water by plant roots and its transpiration based on soil mois ture in the unsaturated root zone In MIKE SHE the ET processes are split up and modelled in the follow ing order 1 A proportion of the rainfall is intercepted by the vegetation canopy from which part of the water evaporates 2 The remaining water reaches the soil surface producing either surface water runoff or percolating to the unsaturated zone 3 Part of the infiltrating water is evaporated from the upper part of the root zone or transpired by the plant roots 4 The remainder of the infiltrating water recharges the groundwater in the saturated zone The primary ET model is based on empirically derived equations that fol low the work of Kristensen and Jensen 1975 which was carried out at the Royal Veterinary and Agricultural University KVL in Denmark In addition to the Kristensen and Jensen model MIKE SHE also includes a simplified ET model that is used in the Two Layer UZ ET model The Two Layer UZ ET model divides the unsaturated zone into a root zone from which ET can occur and a zone below the root zone where ET does not occur The Two Layer UZ ET module is based on a formulation pre sented in Yan and Smith 1994 Its main purpose is to provide an estimate of the actual evapotranspiration and the amo
350. the dispersion coefficients can be written explicitly by combining Eq 19 5 and Eq 19 8 as follows ve vy vi M PE ap Y Ka D QIHH 77 Crary y ATEN 77 ye V5 yi oe janet Dy QTHH 77 Cine 77 QTEV 77 y V5 ya E 4 Z Gd Da ary 77 Gry 77 ivy i VV Dy arm curs Bi De aa 7 an e Vr Vy i 2 2 U mp aran amant Fyz i 2 2 U 19 9 and for symmetrical reasons Dyy D Dyz Dz and Dy Dzy yx Note that Eq 19 9 can simplify to Eq 19 7 if azy 7 apyy a and OrHH OTVH OTHYV OT Burnett and Frind 1987 suggest that the dispersion should at least allow for the use of two transverse dispersivities a horizontal transverse disper sivity and a vertical transverse dispersivity to describe the difference in transverse spreading which is greater in the horizontal plane than in the vertical plane In comparison MIKE SHE uses all five dispersivities The determination of the five dispersivities is always difficult so often one has to rely on experience or on empirically derived values The dispersion term in the advection dispersion equation accounts for the spreading of solutes that is not accounted for by the simulated mean flow velocities the advection Therefore it is obvious that the more accurate you describe the spatial variability in the hydrogeologic regime and if the grid is sufficiently fine i e the variations in the advective velocity the smaller the dispersivities you need to apply in the
351. the irrigation water in the model Sprinkler If the water is applied as sprinkler irrigation it is added to the precipitation component Drip If the water is applied as Drip irrigation it is added directly to the ground surface as ponded water Sheet If the water is applied as Sheet irrigation then an additional data tree item is required to define where the water is to be added within the command area The idea behind this option is that water is flooded onto one or more cells of the command area and then distributed to the adjoining cells as overland flow The sheet irrigation is applied directly to the cells as ponded water All three methods are allowed in the Simple sub catchment based over land flow method However the sheet method does not really make sense if the subcatchment overland flow method is used 74 MIKE SHE Land Use Se License Limited Irrigation License Limited Irrigation IV Include License Limited Irrigation Time Series File E DHI License limitated irrigation dfs0 Ea Edit Sometimes the total amount of irrigation water that a user can apply is limited by a license over a certain period e g 10000 m year The license limited option allows you to specify a dfsO time series file with a time series of maximum amounts If the maximum amount is reached within the license period then the irrigation will be stopped until the next license period when it will be started again The l
352. the same length as the water movement simulation The only restriction is that the start date for the water quality simulation must be within the water movement simula tion Flow Results for Water Quality Simulation A water quality simulation requires the cell by cell water fluxes calcu lated by the water movement simulation However the water quality sim ulation does not have to be the same period as the water movement simulation Therefore the user interface is flexible in how it will use water movement cell by cell flow data 47 Se Setup Data Tab No recycling on results In this case the water quality simulation end date must also be within the water movement simulation period which means that the water quality simulation cannot extend beyond the water movement simulation Recycling on flow results In this case the water quality simulation can be much longer than the water movement simulation based on a repeated set of water movement results The water quality simulation starts on the Start Date with the flow results from the Cycle Restart Date When the water quality simulation period reaches the Cycle End Date the WQ simulation will continue but the flow results will be restarted at the Cycle Restart Date If the recycle dates do not match one of the saved time steps then the nearest saved time step is used For example you may have a two year water movement simulation but you may want to simulate wate
353. the total actual evapotranspiration Direct evaporation from the soil is calculated only for the first node in the soil column 16 1 5 Spatial resolution The finite difference method assumes that the soil profile is divided into discrete computational nodes in which the dependent variable is calcu lated The non linearity of the unsaturated flow process creates large gra dients in soil pressure and soil moisture content during infiltration Therefore it is important to select appropriate nodal increments so as to describe the flow process with sufficient accuracy but at the same time keeping the computational time reasonable This trade off can become especially constraining in catchment scale simulations 272 MIKE SHE Gravity Flow LEA The simulation of Hortonian ponding at the ground surface high rainfall intensity on dry low permeable soil requires a fine spatial resolution in the upper part of the profile see Figure 16 3 Deeper in the profile the gradients are smaller and larger node increments can usually be selected Thus as a general guideline one should choose a finer spatial resolution in the top nodes RAINFALL RAINFALL e S 3 7 zZ o PONDING OCCUR b NO PONDING OCCUR Figure 16 3 Examples of different increments in the soil profile and the resulting water content distribution of 1 3 cm for detailed studies and 3 5 cm for catchment studies Further down in the profile larger increments can be c
354. thin a single cell This results in sudden changes in the vertical location at cell boundaries The following particle sinks can remove particles from model cells e constant concentration boundary receiving particles e well e river e drain connected to a river or the boundary e exchange to the unsaturated zone e constant concentration source with a lower concentration than the cal culated concentration The following particle sources can add particles to model cells e constant concentration boundaries e asolute concentration in precipitation e a source in the saturated zone with a specified mass inflow rate e aconstant concentration source with a higher concentration than the calculated concentration The PT module only calculates particle movements in the saturated zone However the volume of water removed by the wells rivers drains and the unsaturated zone is known This volume of water is used to calculate the number of particles that are removed by each of the sinks using the for mula V Vink L yx 21 11 i Vink Viot n nx Vek where n is the number of particles removed by sink i n is the number of particles in the saturated zone V is the volume of water exchanged with sink i Ving 18 the volume of water exchanged with all sinks V is the total volume of water in the saturated zone Equation 21 11 is used to calculate the number of particles which should be removed by each sink at each
355. ties Editor V 2 p 177 How the water extraction is distributed with depth depends on the AROOT parameter Figure 15 4 shows the distribution of transpiration for different values of AROOT assuming that the transpiration is at the reference rate with no interception loss C 0 and no soil evaporation loss C 0 The figure shows that the root distribution and the subsequent transpira tion becomes more uniformly distributed as AROOT approaches 0 Dur ing simulations the total actual transpiration tends to become smaller for higher values of AROOT because most of the water is drawn from the upper layer which subsequently dries out faster The actual transpiration therefore becomes more dependent on the ability of the soil to conduct water upwards capillary rise to the layers with high root density Figure 15 5 shows the effect of the root depth given the same value of AROOT A shallower root depth will lead to more transpiration from the upper unsaturated zone layers because a larger proportion of the roots will be located in the upper part of the profile However again this may lead to smaller actual transpiration if the ability of the soil to conduct water upwards is limited Thus AROOT is an important parameter for estimating how much water can be drawn from the soil profile under dry conditions Related Items e Kristensen and Jensen method V 2 p 244 e ET Vegetation Properties Editor V 2 p 177 67 LEA Setup
356. time step This is however not necessar ily a whole number of particles The PT module takes care of this by 372 MIKE SHE User s Guide Governing equations Se retaining all the fractions of particles from previous time steps until it can remove a whole particle Particles are always assigned one by one to the sinks with preference given to the sink in need of most particles In case there is more than one sink in a cell with each of these sinks requiring the same number of particles there is a random assignment of one particle to one of these sinks If there are any more particles left after this assign ment the next particle will then go to one of the other sinks Constant concentration sources and sinks at boundaries or inside the model domain are handled by calculating the number of particles that cor responds to the concentration and truncating this value to a whole number For the mass flux source and the precipitation source the concentration is again converted to a number of particles The whole number obtained by truncating this value is added to the compartment containing the source The fractions that are left over after truncation are accumulated until a whole number of particles has been attained in one of the next time steps at which time an additional particle is added to the compartment in which the source is located Drains remove particles to rivers or to the boundary out of the model domain Drains can al
357. tion The solution is obtained when the residual error during an iteration in any computational node is less than the specified tol erance The value of the maximum residual error should be selected according to aquifer properties and dimensions of the model In practice the maximum residual error value will always be a compromise between accuracy and computing time It is recommended to check the water balance carefully at the end of the simulation but it should be emphasized that large internal water balance errors between adjacent computational nodes may not be Technical Reference for Water Movement 305 LEA Saturated Flow Reference detected If large errors in the water balance are produced the maximum residual error should be reduced Drainage with the SOR Solver When the SOR solver is used drainage is only allowed from the top layer of the saturated zone model In this case the new water table position at the end of the time step is calculated from the flow balance equation AS Q q At 17 25 where AS is the storage change as a result of a drop in the water table Qg is the outflow through the drain and Yq represents all other flow terms in a computational node in the top layer i e net outflow to neighbouring nodes recharge evapotranspiration pumping and exchange to the river etc The change in storage per unit area can also be calculated from AS dy d S 17 26 where d is the depth of water a
358. tions at each end of the column However the UZ column only exchanges water with the upper node of the SZ model even if the UZ model extends below the top layer of the SZ model see Limitations V 2 p 287 Upper boundary The upper boundary condition is either e a constant flux condition within each time step Neumann boundary condition which is determined by the infiltration rate or e a constant head condition within each time step Dirichlet boundary condition which is determined by the level of ponded water on the surface If the infiltration is equal to the net rainfall rate at the soil surface R Eq 16 9 can be written for the top node N as WNT WR ne YS Ch At Cee eee a 16 19 2 AZy 0 5 AZy 1 AZ Set where R is defined negative downwards Writing Eq 16 19 in a similar form to Eq 16 11 yields Ay Wht By Wht Dy 16 20 where Ay KR AZ By CRt At KR AZ AE AZ 4 AZy 16 21 Dy Ch Sy 268 MIKE SHE Richards Equation Se If water is ponded on the ground surface the first node is assumed satu rated and the boundary condition simply becomes wit wh AZy 16 22 At the beginning of each UZ time step the amount of available water for infiltration is calculated as the amount of ponded water plus the net rain fall at the ground surface minus evaporation from ponded water The upper boundary condition is applied depending on the deficit in th
359. to In the sub dialogue for each of the parallel baseflow reservoirs you must define the following Specific Yield to account for the fact that the reservoir contains a porous media and is not an actual bathtub Time constant for base flow a calibration parameter that represents the time it takes for water to flow through the reservoir Dead storage fraction the fraction of the received percolation that is not added to the reservoir volume but is removed from the available stor age in the reservoir UZ feedback fraction the fraction of base flow to the river that is avail able to replenish the water deficit in the unsaturated zone adjacent to the river i e the lowest interflow reservoir in the subcatchment Initial depth the initial depth to the water in the reservoir measured from the ground surface 107 Setup Data Tab Threshold depth for base flow the depth below the ground surface when base flow stops The threshold depth must be less than or equal to the depth to the bottom of the reservoir Threshold depth for pumping the depth below the ground surface when pumping is shut off The threshold depth must be less than or equal to the depth to the bottom of the reservoir Depth of the bottom of the reservoir the depth below the ground sur face of the bottom of the reservoir Related Items e Saturated Flow Reference V 2 p 289 e Linear Reservoir Method V 2 p 307 e Calculation of Baseflow
360. transpiration Vegetatio Include Vegetation name Parameters Comments 4 Bare soil User defined Vv Vv 2 HYVv Aman 160d User defined Vv ed 3 JHYV Aman 120d User defined Vv Vv 4 Boro 1454 User defined Vv Vv 5 _ Aus 120d User defined Vv Vv e anet User defined IV Vv Tobacco User defined IV Vv ja Grain User defined Vv Vv ja Potatoes User defined Iv iV Sugarcane User defined Iv VV Homestead User defined Iv IV 12 Crass User defined Iv Vv Spring cereal 28 4 User defined Ci iV Winter Wheat User defined Ci Vv Winter Barley User defined Ci Vv Winter rye 25 9 User defined E V q 17 Winter rane 15 0 ll ser defined ri ji oa zi The vegetation database is populated with data in a number of steps Firstly all the vegetation types to be included in the database are entered in a table in the Vegetation Setup Menu The data needed are MIKE SHE Editors k 177 ET Vegetation Properties Editor 7 1 2 e Vegetation name e Vegetation Development Include Irrigation e Evaporation parameters If the Irrigation module is used in the model you may chose to use the irrigation demand values from the vegetation file In this case you should select the Include Irrigation option and then specify the irrigation demand parameters by vegetation type You can also specify specific Evaporation Parameters for each vegetation type If the
361. tration capacity and the soil moisture contents at the wilting point field capacity and saturation The output is an estimate of the actual evapotranspiration and the ground water recharge 254 MIKE SHE Simplified ET for the Two Layer Water Balance Method a oe 15 2 1 Sublimation from Snow If the air temperature is below the Threshold melting temperature then the water will be removed from the snow storage as sublimation before any other ET is removed using E snow Reference_ET At 15 11 where Reference_ET refers to the Reference Evapotranspiration V 2 p 79 before being reduce by the Crop Coefficient ke that is speci fied in the Vegetation Development Table V 2 p 180 If there is not enough snow storage then E will reduce the snow storage to zero 15 2 2 Canopy Interception Interception is defined as the process whereby precipitation is retained on the leaves branches and stems of vegetation This intercepted water evap orates directly without adding to the moisture storage in the soil The interception process is modelled as an interception storage which must be filled before stem flow to the ground surface takes place The size of the interception storage capacity Iinq depends on the vegetation type and its stage of development which is characterised by the leaf area index LAI Thus I C max LAI 15 12 int where C 1S an interception coefficient mm and LAJ is leaf area ind
362. ttom of the reservoir perco lation stops Interflow time constant a calibration parameter that represents the time it takes for water to flow through the reservoir to the next reservoir Percolation time constant a calibration parameter that represents the time it takes for water to seep down into the baseflow reservoir 105 LEA Setup Data Tab Interflow threshold depth the depth below the ground surface when interflow stops If interflow stops percolation will continue until the reservoir is empty i e the water level reaches the bottom depth The threshold depth must be less than or equal to the depth to the bottom of the reservoir Related Items e Saturated Flow Reference V 2 p 289 e Linear Reservoir Method V 2 p 307 e Calculation of Interflow V 2 p 313 2 16 2 Baseflow Reservoirs Name Global Fraction of percolation to reservoir 1 fo Fraction of pumping from reservoir 1 fo Use default river links Vv Specific yield i Time constant For base flow fo A Dead storage fraction io 6hCCU U2 feedback fraction pooo Initial depth jbo mwm Threshold depth for base flow o mw Threshold depth for pumping oc m Depth to the bottom of the reservoir wE m In the Linear Reservoir Method in MIKE SHE each baseflow reservoir is divided into two parallel baseflow reservoirs The two parallel baseflow reservoirs each receive a fraction of the percolation water from the inter flow reservoirs
363. tup Data Processed In the Setup Tab you specify the input data required by the model including the Model Domain and Grid However most of the Setup Data is independent of the Model Domain and Grid When you pre process you model set up MIKE SHE s pre processor program scans through your model set up and interpolates all spatial data to the specified model domain and grid This interpolated set up data is stored in a fif file which is read during the simulation by the MIKE SHE engine However the fif file does not include any time information All time series information is interpolated dynamically during the run This is necessary because the time steps in MIKE SHE can dynamically change during the simulation in response to stresses on the system The Preprocessed Data Tab is used to display the spatial content of the fif file Before you run your simulation you should carefully check the preproc essed data for errors Errors found in the preprocessed data are typically related to incorrectly specified parameters file names etc in the Setup Tab The Preprocessed Tab includes a data tree with two items e Processed Data V 2 p 146 e GeoScene3D V 2 p 152 145 LEA Preprocessed Data Tab 3 1 Processed Data Preprocessed Data Load JEN7 8D and Sales BD Visits 2006 Canada Sept06 Napa2007 Napa Valley FD Results Napa Valley FD Model Napa Valley FD Mc There is only one button in the main dialogue f
364. ty at saturation the field capacity and the wilting point However this we strongly advise against this because the cubic spline function is unlikely to be able to fit an appropriate function to only 3 points Van Genuchten and Campbell Functions In addition to the tabulated values parametric functions are available using the Van Genuchten and the Campbell formulations It is important to note that the data is tabulated internally and stored in the same form as if tabulated data were input Hydraulic Conductivity Function The Governing Equation for the unsaturated flow requires information about two hydraulic functions The hydraulic conductivity function K and the soil moisture retention curve y 8 are important The hydraulic conductivity decreases strongly as the moisture content 0 decreases from saturation This is not surprising since the total cross sec tional area for the flow decreases as the pores are getting filled with air In 174 MIKE SHE Hydraulic Conductivity Function LAA 6 2 1 Tabulated 6 2 2 Averjanov addition when a smaller part of the pore system is available to carry the flow the flow paths will become more tortuous Also there is an increase of the viscosity of the water when the short range adsorptive forces become dominant in relation to the capillary forces The experimental procedure for measuring the K 0 function is rather dif ficult and not very reliable Alternatively procedures h
365. uctivity K the SOR solver distinguishes between conditions where the hydraulic conductivity of layer k is greater than or less than the hydraulic conductivity of layer k These cases are shown in Table 17 1 and Table 17 2 MIKE SHE 3D Finite Difference Method Table 17 1 For the case when Kx lt Kx41 Layer k confined unconfined _ Ag AZ 1 K Az AZk 1 confined Az Y AZk4 p amp r K K K Layer k 1 k 1 k k 1 K AZ Zk 1 K AZ AZ 1 unconfined hki Zka V Akai hh Zkari hk Kya Kyi K Ah hg h hg41 Table 17 2 For the case when Kp gt Kk41 Layer k confined unconfined _ A AZ 4 1 K AZ AZk 1 fined AZk 1 AZk 1 confine Kya Kia Layer Ah hy Nga Ah 2 amp 41 Mga k 1 a AZ Zk 1 K AZ Zk 1 unconfined hea Zk 1 J hes Zk 1 Kya Kya Ah hy hy 4 Ah Zea Nga The transient flow equation yields the finite difference expression 5 At he l_pp 20 17 24 where S is the storage coefficient and Af is the time step Eq 17 24 is written for all internal nodes N yielding a linear system of N equations with N unknowns The matrix is solved iteratively using a modified Gauss Seidel method Thomas 1973 Technical Reference for Water Movement 303 Saturated Flow Reference Horizontal view Figure 17 5 Spatial discretisation Vertical view ax 4 amp 2 A2 Figure 17 6 Types of
366. ugate gradient solver Hill 1990 The PCG solver includes both an inner iteration loop where the head dependent boundaries are kept constant and an outer iteration loop where the non linear head dependent terms are updated The PCG solver includes a number of additional solver options that are used to improve convergence of the solver The default values will generally ensure good performance For the majority of applications there is no need to adjust the default solver settings If on the other hand non convergence or extremely slow convergence is encountered in the SZ component then some adjustment of the solver settings may help The PCG solver in MIKE SHE which is identical to the one used in MODFLOW McDonald and Harbaugh 1988 requires a slightly differ ent formulation of the hydraulic terms when compared to the SOR solver Potential flow terms The potential flow is calculated using Darcy s law Q AhC 17 2 where Ah is the piezometric head difference and C is the conductance The horizontal conductance in Eq 17 2 is derived from the harmonic mean of the horizontal conductivity and the geometric mean of the layer thickness Thus the horizontal conductance between node i and node 1 1 will be KH 14 4 KH je Azii jet AG jk Goy a KH e KH jy 17 3 i 1 j where KH is the horizontal hydraulic conductivity of the cell and Az is the saturated layer thickness of the cell The vertical conductance bet
367. uhe ce 9 ee o eo ed whe ee eee Be 134 2 18 Storing of Results sf eek cd kee eae od Ge Ke ale ee a we a 135 2 18 1 Detailed time series output naaa a 138 2 18 2 Detailed MIKE 11 Output 141 2 18 3 Gridseriesoutput 2 00000000 143 2 19 ExtraParameters oe ssas ca dea ata eaa eee ee 144 3 PREPROCESSED DATA TAB 0 a 145 3 1 Processed Data c csaa ge par emden da D A a AOS E O a Ar 146 3 1 1 Model Domain and Grid aaa aaa a aa 147 3 1 2 Precipitation and Evapotranspiration 148 3 1 3 River LinksS 24 4 2 206409 a oe Db we Paw a eae S Band 148 3 1 4 UZ Soil Profile Grid Codes 2 22 222222002 149 3 1 5 UZ Classification Grid Codes 150 3 1 6 Saturated Zone ltems 151 3 1 7 Saturated Zone Drainage 151 3 2 GeoScenesD esde 626866 6 an eb eee ee Oo dew ewe dg 152 4 RESULTSTAB 2 000002 ee 155 4 1 MIKE SHE Detailed Time Series 156 4 2 Gridded Data Results Viewer 00000 4 157 4 2 1 The Result Viewer setup file already exists warning 158 4 3 MIKE 11 Detailed Time Series 159 4 4 RunStatistics 0 000000 02 ee 160 4 4 1 Shape file output for run statistics 161 4 4 2 Statistic Calculations 0 161 4 5 GeoScene3D 0 0 0 0 00000 ee 163 MIKE SHE Edito
368. unt of water that recharges the saturated zone It is primarily suited for areas where the water table is shallow such as in wetland areas Leaf Area Index LAI The area of leaves above a unit area of the ground surface is defined by the leaf area index LAI Usually generalised time varying functions of the LAI for different crops have been established Thus in MIKE SHE the Technical Reference for Water Movement 243 Evapotranspiration Reference user must specify the temporal variation of the LAI for each crop type dur ing the growing seasons to be simulated Different climatic conditions from year to year may require a shift of the LAI curves in time but will generally not change the shape of the curve Typically the LAI varies between 0 and 7 Root Depth The root depth is defined as the maximum depth of active roots in the root zone 15 1 Kristensen and Jensen method The primary ET model is based on empirically derived equations that fol low the work of Kristensen and Jensen 1975 which was carried out at the Royal Veterinary and Agricultural University KVL in Denmark In this model the actual evapotranspiration and the actual soil moisture sta tus in the root zone is calculated from the potential evaporation rate along with maximum root depth and leaf area index for the plants The empirical equations in the model are based on actual measurements The model gen erally assumes the temperature to be above
369. up tab In m 1 3 s L_ m L_ C c L E m L_ al Lo E L_ other words if the overland flow is not included in the Simulation Speci fication V 2 p 26 dialogue then the Overland item will not be included in the pre processed data tree 3 1 1 Model Domain and Grid The model domain and grid item displays the grid code values required for the MIKE SHE model This differs slightly from the Model Domain and Grid V 2 p 52 item in the Setup Tab In the fif file all cells outside the model domain are assigned a value of zero compared to the Setup tab were the cells outside of the model boundary are delete values Unlike other data items in the pre processed tab you cannot save the pre processed model domain and grid to a dfs2 file and re use it in the Setup Tab because the Model Domain and Grid V 2 p 52 item requires delete values outside of the model domain 147 LAA Preprocessed Data Tab Related Items e Model Domain and Grid V 2 p 52 3 1 2 Precipitation and Evapotranspiration The precipitation and evapotranspiration items display the integer station codes for the time series defined in Precipitation Rate V 2 p 58 and Ref erence Evapotranspiration V 2 p 79 items in the Setup Tab The station names are not displayed so you will have to refer back to the Setup Tab for the station names However the fif file does not include any time information All time series inf
370. urant criteria see the Courant criteria V 2 p 217 Common stability parameters The common stability parameters are used by both the implicit SOR solver and the explicit solver Threshold water depth for overland flow This is the minimum depth of water on the ground surface before overland flow is calculated Very shallow depths of water will normally lead to numerical instabilities The default value is 0 0001 m The threshold depth for overland flow should not be confused with the Detention Storage V 2 p 84 The detention storage is related to the amount of water stored in local depression on the ground surface which must be filled before water can flow laterally to an adjacent cell 36 MIKE SHE Simulation Specification LEA Threshold gradient for applying low gradient flow reduction In flat areas with ponded water the head gradient between grid cells will be zero or nearly zero and numerical instabilities will be likely To dampen these numerical instabilities in areas with low lateral gradients a damping function has been implemented The damping function essentially increases the resistance to flow between cells This makes the solution more stable and allows for larger time steps However the resulting gradients will be artificially high in the affected cells and the solution will begin to diverge from the Mannings solution At very low gradients this is normally insignificant but as the gradient increases the differen
371. urce It is used by the interpolation algorithm to assign a source location to the satu rated or unsaturated zone cells Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Source Sinks Boundary Conditions and other Exchanges V 2 p 338 in the saturated zone e Solute Transport in the Unsaturated Zone V 2 p 340 133 Ss Setup Data Tab 2 17 4 Strength e Source Sinks Boundary Conditions and other Exchanges V 2 p 343 in the unsaturated zone Strength dialogue Type Time varying Real Data EUM Data Units Grid Code Time Series EUM Data Concentration Units Since the source is a common data item for overland unsaturated and sat urated flow the units of the source strength depend on the type of source being simulated The source strength comprises both a distribution and a value The distri bution can be either uniform station based or fully distributed If the data is station based then for each station a sub item will appear where you can enter the time series of values for the station If the data is fully distrib uted then you can enter a time varying dfs2 file Related Items e Solute Transport in the Saturated Zone V 2 p 329 e Source Sinks Boundary Conditions and other Exchanges V 2 p 338 in the saturated zone e Solute Transport in the Unsaturated Zone V 2 p 340 e Source Sinks Boundary Conditions and other Exchanges V 2 p 343 in the unsaturated zone e
372. urface conditions If the UZ feedback is not included uncertainty of the time constants will only affect routing of the baseflow and interflow components while the total volumes of runoff will remain unchanged If UZ feedback from the baseflow reservoir is included some of the baseflow to the stream will be transferred to the UZ storage because of ET in the unsaturated zone Technical Reference for Water Movement 311 LEA Saturated Flow Reference Qr river Interflow Reservoirs Baseflow Reservoirs Figure 17 10 Schematic flow diagram for the Subcatchment based linear reser voir flow module 17 2 3 Subcatchments and Linear Reservoirs Three Integer Grid Code maps are required for setting up the framework for the reservoirs e a map with the division of the model area into Subcatchments e a map of Interflow Reservoirs and e amap of Baseflow Reservoirs The Interflow Reservoirs are equivalent to what was called the Topo graphic Zones in earlier versions of the Linear Reservoir module in MIKE SHE There is no limit on the number of subcatchments or linear reser voirs that can be specified in the model 312 MIKE SHE Linear Reservoir Method LAA The division of the model area into subcatchments can be made arbitrarily However the Interflow Reservoirs must be numbered in a more restricted manner Within each subcatchment all water flows from the reservoir with the highest grid code number to the rese
373. used by the particle model to calculate u X t using linear interpo lation for the spatial interpolation in the three directions in the grid cells For time integration simple Eulerian integration is used The numerical input used by the water movement calculations is reused in the particle model as control volumes see 21 9 and for the specification of initial and boundary conditions Horizontal movement is only allowed in saturated parts of the SZ model domain If INITSPEC 2 is used the particles are also moved horizontally in the fictitious thin saturated part at the bottom of dry layers For all other values of INITSPEC there is only vertical movement in the dry lay ers The different handling of the INITSPEC 2 option was introduced to allow for a similar behaviour of PT compared to the original finite differ ence AD solution The vertical position of the particles is corrected for changes in cell thick ness when a particle moves horizontally from one cell to the next The cor rection uses the relative vertical location at the old location to determine the new vertical location _ Zo1a Bottom ig Znew Te To x ToP pew Bottom ey Bottom 21 10 new 371 Particle Tracking Reference where old indicates the previous cell and new the current cell The correc tion is only applied when moving horizontally from one cell to the next i e there is no interpolation of layer thickness during the movement wi
374. utput V 2 p 138 Grid series output V 2 p 143 e MIKE 11 Detailed Time Series V 2 p 159 2 18 3 Grid series output Enable tem Reauivedtfor 5 _ crop coefficient Nag mi actual evapotranspiration Nag V actual transpiration Weter Balance Nar VV actual evaporation from interception Water Balance Nar IV actual evaporation from ponded water Water Balance Nar canopy interception storage Water Balance Nap mV levapotranspiration from SZ Water Balance Nar IV depth of overland water Water Balance Nar IV overland flow in x direction Water Balance Nag IV overland flow in y direction Water Balance Nag iV External sources to Overland for OpenMl Water Balance Nag Nae ae Maximum water content 2layer UZ 19 Minimum water content 2 layer UZ The Grid series output dialogue allows you to specify the frequency at which you want detailed output of gridded data and the items that you want output A list of available Data Types can be found in Output Items V 1 p 87 The list is dynamic in the sense that the list changes in response to the processes included in the Simulation Specification dia logue In some cases such as when the Water Balance output has been specified see Storing of Results some of the items will be automatically selected and cannot be unselected This will be noted in the Required for column of the dialogue 1
375. ve the water table which is a function of the available unsaturated storage 282 MIKE SHE Coupling the Unsaturated Zone to the Saturated Zone LAA and soil properties and the amount of net groundwater flow horizontal and vertical flow and source sink terms The main difficulty in describing the linkage between the two the satu rated SZ and unsaturated UZ zones arises from the fact that the two components UZ and SZ are explicitly coupled i e run in parallel and not solved in a single matrix with an implicit flux coupling of the UZ and SZ differential equations Explicit coupling of the UZ and SZ modules is used in MIKE SHE to optimize the time steps used and allows use of time steps that are representative of the UZ minutes to hours and the SZ hours to days regimes MIKE SHE overcomes problems associated with the explicit coupling of the UZ and SZ modules by employing an iterative procedure that conserves mass for the entire column by considering out flows and source sink terms in the saturated zone Error in the mass balance originates from two sources 1 keeping the water table constant during a UZ time step and 2 using an incorrect esti mate of the specific yield S the difference between the moisture content at saturation 0 and moisture content at field capacity 0 in the SZ cal culations This is illustrated in Figure 16 7a If outflow from the SZ is neglected it appears from the figure that during th
376. view However the MIKE 11 river network is not transferred as an overlay Layer number for Groundwater Items For 3D SZ data files the layer number can be specified at the top of the table However the layer number can be changed from within the Results Viewer see Changing to a different SZ layer V p 117 By default the top layer is dis played Add XY flow Vectors Vectors can be added to the SZ plots of results by checking the Add X Y flow vectors checkbox These vectors are calcu lated based on the Groundwater flow in X direction and Groundwater flow in Y direction data types if they were saved during the simulation In the current version velocity vectors cannot be added for overland flow output file name The file name column shows the name of the result file from which the gridded data will be extracted 157 a oe Results Tab Related Items e Grid series output V 2 p 143 e The Results viewer V p 95 4 2 1 The Result Viewer setup file already exists warning When the Result Viewer opens one of the items in the table it creates a setup file for the particular view with the extension rev The name of the current setup file is displayed in the title bar of the dialogue Initially the rev file includes only the default view settings and the overlay informa tion from MIKE SHE However if you make changes to the view such as changes the way contours are displayed then when you close the vi
377. w the threshold there is no baseflow Similar to Eq 17 39 for each Baseflow Reservoir dh E d n 4B pum B a ae 17 49 y where qzy is the amount of inflow to each base flow reservoir qg is the amount of baseflow out of the reservoir and pump is the amount of water removed via extraction wells from each reservoir Both qzy and qpump are controlled by split fractions that distribute qzy and qpump between the two parallel baseflow reservoirs Each Baseflow Reservoir can be treated as A Single Linear Reservoir with One Outlet p 308 Thus as long as the water level is above the threshold water level for the reservoir i e there is still baseflow out of the reser voir dt dt kpSy kps h h e ain Ipump 17 17 50 where k is the time constant for the Baseflow Reservoir The formula for a single outlet is applicable because there is no time con stant associated with the pumping However Qpump is also controlled by a threshold level in this case a minimum level below which the pump is turned off Since this minimum level is independent of the threshold level for the reservoir itself a case could arise whereby there was pumping but no baseflow from the reservoir In this case h h d din Ipung t 17 51 y to 316 MIKE SHE Linear Reservoir Method a oe If there is no pumping and no baseflow out then the expression for the water level in the reservoir simply b
378. ween two cells is computed as a weighted serial connection of the hydraulic conductivity calculated from the middle of layer k to the middle of the layer k 1 Thus 2 AA ERR ee 17 4 Az 2 AZk 1 2K 2K k 1 290 MIKE SHE 3D Finite Difference Method a oe where 4z is the layer thickness Dewatering conditions Consider the situation in Figure 17 1 where the cell below becomes dew atered Figure 17 1 Dewatering conditions in a lower cell The actual flow between cell k and k is arin CVkinl rop k 17 hi 17 5 In the present solution scheme the flow will be computed as akay Very gs 1 hy 17 6 Subtracting Eqs 17 5 from 17 6 gives the correction term qe Cvka lhk 1 Ztop k 41 17 7 which is added to the right hand side of the finite difference equation using the last computed head A correction must also be applied to the finite difference equation if the cell above becomes dewatered Technical Reference for Water Movement 291 Saturated Flow Reference Figure 17 2 Dewatering conditions in the cell above Thus from Figure 17 2 the flow from cell k to k is adr CVp_y Ag _1 Zrop k 17 8 where again the computed flow is ak CVg_y Ag_ 1 hy 17 9 Subtracting Eqs 17 8 from 17 9 gives the correction term qe CVg_v Ztop k Me 17 10 which is added to the right hand side of the finite difference equation using the last computed head Stor
379. wever often the vertical hydraulic conductivity of the upper layer in the saturated zone does not represent the permeability of the top layer of the soil The soil layers are usually described in more detailed in the UZ model than in the SZ model but the UZ parameters are not used when UZ disappears To handle such situations a leakage coefficient can be specified The exchange of water between the surface water and ground water is then cal culated based on the specified leakage coefficient and the hydraulic head between surface water and ground water In other words the UZ model is automatically replaced by a simple Darcy flow description when the pro file becomes completely saturated This option is often useful under lakes or on flood plains which may be permanently or temporarily flooded and where fine sediment may have accumulated creating a low permeable layer lining with considerable flow resistance The value of the leakage coefficient may be found by model calibration but a rough estimate can be made based on the satu rated hydraulic conductivities of the unsaturated zone or in the low perme able sediment layer if such data is available The specified leakage coefficient is used wherever it is specified In areas where a delete value is specified the vertical hydraulic conductivity of the top SZ layer is used In the processed data the item Overland SZ Exchange Grid Code is added where areas with full contact are
380. wizard click on the Finish button which will temporarily save your setup If you click Cancel your setup will not be saved After clicking Finish you must click the Save icon in the top menu bar to permanently save your setup 206 MIKE SHE TECHNICAL REFERENCE FOR WATER MOVEMENT 207 208 MIKE SHE Se 12 WATER MOVEMENT OVERVIEW This section includes detailed descriptions of the numeric engines used for moving water in MIKE SHE including Overland Flow Reference Finite Difference Method Simplified Overland Flow Routing Channel Flow Reference Evapotranspiration Reference Kristensen and Jensen method Simplified ET for the Two Layer Water Balance Method Unsaturated Flow Reference Richards Equation Gravity Flow Two Layer Water Balance Saturated Flow Reference 3D Finite Difference Method Linear Reservoir Method Technical Reference for Water Movement 209 Water Movement Overview 210 MIKE SHE Finite Difference Method a oe 13 OVERLAND FLOW REFERENCE When the net rainfall rate exceeds the infiltration capacity of the soil water is ponded on the ground surface This water is available as surface runoff to be routed downhill towards the river system The exact route and quantity is determined by the topography and flow resistance as well as the losses due to evaporation and infiltration along the flow pa
381. xample j k and the weights 6 and 6 are determined in such a way that the scheme becomes third order accurate The determination of the MIKE SHE User s Guide Solute Transport in Overland Flow Se weights is demonstrated in Vested et al 1992 and listed in Table 19 3 The other boundary concentrations are found in a similar way Table 19 3 Weight functions for advective transport I a B 1 0 0 7 6 Ox 2 1 3 o o 7 6 o 2 1 3 2 Ox Q1 63 Q4 05 oy B B3 B4 Bs 3 0 1 6 0 7 6 oy 1 6 02 6 4 6 o 2 oy7 2 Oy 6 2 6 7 2 5 Ox Oxoy 2 Oy 6x0 2 The locations of the weights are determined by the points that enter into the discretisation Since the scheme is upstream centred the weights are positioned relative to the actual direction of the flow This is outlined in more detail for in the saturated zone Solution Scheme p 334 section The dispersive transport can be derived in a similar way With the finite difference formulation of the dispersive transport components based on upstream differencing in concentrations and central differencing in disper sion coefficients the transport in the x direction can be written as Dag Draper Das CET in Ax Y Dopu Don ciwi Carel Ciki Cji 4dyAx 19 32 The dispersive transport in the y direction is done in a similar way The dispersive transports are incorporated in the w
382. xtract the UZ classifica tion grid codes The extracted dfs2 file can be edited in the 2D editor as desired and used to specify UZ computational grids Related Items e Unsaturated Flow Reference V 2 p 261 e Lumped UZ Calculations V 2 p 281 98 MIKE SHE Unsaturated Zone 2 14 6 2 Layer UZ soil properties Profile ID 11 DLoam Grid code value Bypass const Soil water content at saturated conditions 0 4 byp 0 5 Soil water content at field capacity 0 35 thi 0 4 Soil water content at field wilting point 0 2 thr2 10 3 Infiltration rate 1e 006 m s 2 Layer UZ Soil Properties Conditions when Unsaturated Flow selected in the Simulation Specification dialogue and the Two Layer Water Bal ance method selected for the numeric engine dialogue Type Integer Grid Codes with sub dialogue data EUM Data Units Grid Code The first part of the soil profile definition is to define the areas with the same soil types Below this initial item a separate item will appear for every unique Grid Code in the file in which the soil characteristics are defined In this soil properties dialogue there are three sections Header The header includes the Profile ID which is the editable name displayed in the data tree for this profile and the Grid Code value which is read from the Grid Code file Soil Properties In the Two Layer Water Balance method the soil database is not used Instead there are four pri
383. ys and the MIKE SHE result files that should be used 9 3 1 Display The display items are automatically carried over from the MIKE SHE Setup The Display dialogues are exactly the same controls as those used in the MIKE SHE Setup Tab Related items e Display V 2 p 20 in MIKE SHE Setup 9 3 2 Flow model setup Flow Model Setup Water movement simulation C Work main Products Source MSHE RegTest 4D Karup KarupForAD SHE Z Use specific yield From Flow madel for porosity Import overlays From she file You must specify a MIKE SHE water movement SHE simulation that has been run The MIKE SHE output must include the e head elevation in the saturated zone e groundwater flow in the x direction e groundwater flow in the y direction and e groundwater flow in the z direction Use specific yield from flow model for porosity The flow velocity is controlled by the effective porosity However a standard MIKE SHE flow does not include the effective porosity as a parameter The Specific yield is a reasonable approximation for the effective porosity in most cases In the current version MODPATH will always use the specific yield for effective porosity Import overlays from she file By default the MIKE SHE overlays will be displayed in the Particle Tracking Editor but this can be disabled by unchecking this checkbox 196 MIKE SHE Simulation Tab Se Specify the MIKE SHE setup file to use for the simulation

MIKE SHE USER MANUAL VOLUME 2: REFERENCE

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