MIKE SHE WM – User Manual - National Vandressource Model
Contents
1. e REGZONEFILE The PT module uses the concept of registration cells This is intended for registering particle data when particles enter certain model compartments Registration cells can be used to delineate capture zones or to observe particles passing through some region of interest The information on the registration zones is stored in the regzone dig file This is a type 32 type dig file containing polygons or points The program interpretes the lines in the digfile as a code x coordinate y coordinate layer number The first polygon point should have code 1 the last point should have code 3 and the points in between have to have code 2 This is as for a normal type 32 dig file Appendix A 5 of the Pre and Postprocessing Module User Guide with this difference that the fourth field is used for the layer number An example is shown in Figure 3a The user can also identify registration cells using single points The lines have the same appearance as in the type 32 above but the code in field 1 should be 3 for each of the points and each line corresponds to a single point An example is shown in Figure 3b Notice if there are no registration cells the name of the regzonefile is omitted from the input DHI Software 2000 6 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj Filetype Datatype Verno 32 0 540 Textline Registration zone code file2. MIKE SHE WQ User Manual Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj DHI Water amp Environment DHI Institut for Vand amp Milj CONTENTS DHI Software 2000 MIKE SHE WQ Particle Tracking Module i DHI Water amp Environment DHI Institut for Vand amp Milj DHI Software 2000 ii MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj 1 INTRODUCTION This document serves as the users manual and technical reference for the MIKE SHE Particle Tracking PT module PT allows the user to calculate the flow path of a number of hypothetical particles which are moved in the three dimensional saturated groundwater zone SZ The particles are displaced individually in a number of time steps The movement of each particle is composed of a deterministic part in which the particle is moved according to the local ground water velocity calculated by the MIKE SHE water movement module and a stochastic part where the particle is moved randomly based on the local dispersion coefficients Particle tracking is only calculated for the saturated zone SZ and particles that leave SZ are not traced any further Initially the user assigns a number of particles to the compartments of the model grid the computational cells Input of particles during the calculation can occur from sources in the precipitatio
3. If the particle is taken out of the model domain it is registered together with a code of the sink that caused the particle to leave the domain DHI Software 2000 MIKE SHE WQ Particle Tracking Module 13 DHI Water amp Environment DHI Institut for Vand amp Milj This allow s the output retrieval to create digfiles containing the following result types 1 Birth locations of particles datatypes 11217i i 1 6 For each calculation layer the birth locations of all particles that have gone to a certain sink The correspondence between the sink code and the data types is listed in table 4 Table 4 Possible Datatypes and corresponding Sink Codes datatype sinkcode meaning 112171 no active cell particles are only registered here if they arrive in an active cell that is at the same time a registration cell 112172 2 particles gone to rivers 112173 3 particles gone to drains 112174 4 particles gone to wells 112175 5 particles gone to the unsaturated zone 112176 7 13 particles gone to all other sinks When delineating capture zones for complex flow situations both registration zone codes and sink codes are needed as particles from the same cell can move to different cells different sinks within the same cell or move through more than one registration cell Therefore the output retrieval utility will store the registration cell code instead of the sink c
4. 11 12 13 From menu T 1 2 specify the dispersivities From menu T 2 specify species definition name e g Particle Notice The Particle Tracking module only supports one species If option 3 I was utilised From menu T 2 1 specify initial concentration for all layers From menu T 3 specify simulation period The simulation period should be long often more than 100 years so that all groundwater compartments have been age determined From menu T 3a toggle the saturated zone and the sources precipitation infiltration buttons From menu T 3b specify the storage time steps Storage time step should be large to correspond to the long simulation period In the first line in menu T 1 11 specify 1 Location number 1 li Type 1 iii Spatial distribution 1 uniformly distributed precipitation source or iv Spatial distribution 2 file distributed precipitation source Too many particles will slow down the calculation whereas too few particles will produce an inaccurate result A trial and error procedure is recommended for determining an appropriate number of particles In the first line of menu T 2 6 specify 1 Location number 1 i Time series value 2 Constant number of particles in the precipitation or iii Time series value TO file describing the temporal variation of number of particles in the precipitation iv Record number 1 Save the AD set up Run the MIKE SHE particle tracking menu T 4 7
5. 2 Specify any positive number for the particle mass particle mass is not used for delineation of capture zones 3 Specify the initial number of particles in each grid cell Initially 2 particles INITSPEC 2 in each grid cell is appropriate for many applications A larger number of particles will result in more accurate results but will slow down calculations The initial number of particles should also be larger for coarse spatial discretisations in which a small number of compartments is used to represent the model domain Notice If particles are located in constant concentration cells initially these cells will behave as particle sources so in some applications it might be better to use the INITSPEC 1 option and specify the particle numbers in the AD menu system see b 5 below 4 Specify the registration zones single cells or areas in a digfile 5 Disable the extended print to the binary file by setting LPTBIN false DHI Software 2000 MIKE SHE WQ Particle Tracking Module 15 DHI Water amp Environment DHI Institut for Vand amp Miljo 6 1 2 Upstream Zones DHI Software 2000 6 Save the Transport Setup File b From the AD menu system do as follows 1 From menu T 1 select the Flow Result File lt setupname gt frf which will provide the transient or steady state flow field From menu T 1 1 specify porosity From menu T 1 2 specify no dispersion 4 From menu T 2 specify species definition name e
6. Dig files with the travel times of DHI Software 2000 particles and the registration cell number of registered particles or the negative value of the sink type code if the particle has been removed from SZ in a cell which is not a registration cell The types are analogues to 11217i but with the last two columns switched There is one file for each of the possible sink codes 112181 particle that have reached active cells which are registration zone cells 112182 particles that have gone to a river sink 112183 particles that have gone to a drain sink 112184 particles that have gone to a well sink 112185 particles that have gone to the unsaturated zone 112186 particle that have gone to all other sinks Each line contains the values e birth x coordinate e birth y coordinate e travel time day e registration cell number or negative value of sink type 10 DHI Water amp Environment DHI Institut for Vand amp Milj MIKE SHE WQ Particle Tracking Module In the AD output retrieval menu menu U 9 the user also has to specify the output date output file name and output location only layer is important ix iy and Qstat no can be any number For plotting of results it is recommended to utilise the Graphical Presentation tool and follow the specifications given for this tool Select menu G 1 Graphical Presentation e Select the flow result file lt setupname gt frf which provide
7. u u tuu u Bu lu u tul 7 5 B luf 2uu u 7 6 and DHI Software 2000 MIKE SHE WQ Particle Tracking Module 19 DHI Water amp Environment DHI Institut for Vand amp Milj 2 ar u D 0 0 0 2 a u D 0 7 7 0 0 2 ar u D are the longitudinal and transversal dispersion coefficients respectively and D is the neutral dispersion Using equation 6 2 repeatedly the location of a particle at time t NAt can be determined equation 6 8 4d Xpat V D X t Xpat Z pan NAT 7 8 n 0 After applying equation 7 8 for a large number of particles N the average solute concentration for an arbitrary volume can be calculated using equation 7 9 1 1 X eV 5 i 7 9 ea ny f X EV un where is the particle mass Using this procedure an accurate solution of the advection dispersion equation eq 7 1 can be obtained Thompson et al 1987 Thompson and Dougherty 1988 Kitanidis 1994 The term V D X t in equations 7 2 and 7 8 is assumed to be much smaller than the remaining term and is omitted for the benefit of the computational speed This may however in some situations result in an accumulation 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 o
8. TECHNICAL REFERENCE In the earlier applications of particle models solute transport problems were solved using particles as an alternative to finite difference or finite element solutions of the advection dispersion equation DHI Software 2000 18 DHI Water amp Environment DHI Institut for Vand amp Milj MIKE SHE WQ Particle Tracking Module ZE eV u V D Vc 0 TD where c is the solute concentration t is time u is the ground water pore velocity and Dis 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 particle mass is associated to each particle which means that location of a number of particles in a specific volume here defined by the numerical grid used for the water movement calculations corresponds to a solute concentration For isotropic conditions in the soil matrix the displacement of a particle p is described by the following equation Thompson 1987 Xira X t n u x 22 pn 1 V D D X p n t JJar B Konst t Lomi VAL 7 2 where X is the particle coordinates Ar f t is the time step length Z n4118 Vector containing three independent random numbers equally distributed in the interval 1 1 and B RB 7 3 where u u ctun u B u u u u po mtu y Blu
9. arrive in certain cell s The concept is most often used in relation to wells and then is intended to delineate the area contributing water to a certain well The current version of the PT module provides several output data types which can aid at delineating capture zones A first group of data types is related to the registration cells e In the regzone file the user specifies coordinates for the cells which are registration cells e During the simulation the particles are moved according to the groundwater velocities and the user specified dispersion coefficients When a particle enters one of the user specified registration cells the initial location of the particle birth location the current location and the transport time time of particle birth current time are registered e This enables the Particle Tracking module to produce the following result types 1 Capture zones datatype 112141 For each calculation layer a grid map containing numbers which identify the registration cells to which the most recent particle from the grid cell entered 2 Number of registered particles datatype 112131 For each calculation layer a grid map defining the number of particles that has reached a registration cell 3 Transport time datatype 112151 For each calculation layer a grid map defining the transport time to the nearest registration zone cells A second group of data types is related to the concept of sink codes
10. g Particle Notice The Particle Tracking module only supports one species 5 From menu T 2 1 specify the initial concentration If a positive value for INITSPEC is used see a 3 above the concentration input in the menu is is not used for delineation of capture zones and any concentration can be used 6 From menu T 3 specify simulation period The simulation period should be long often more than 100 years One should not worry about taking too long a simulation period the simulation time is proportional to the number of particles and this number in the absence of any sources will decrease with time as the wells remove the particles 7 From menu T 3a toggle the saturated zone button Only the saturated zone is supported by the particle tracking module 8 From menu T 3b specify the storage time steps Storage time step should also be large in accordance with the long simulation period 9 Savethe AD setup 10 Run the MIKE SHE particle tracking menu T 4 pa c Retrieve datatype 211174 containing the birth locations Upstream zones can be used to identify the origin of water that passes through a certain area of intrest Areas of intrest could be the location of an ecologically important habitat that is exchanging water with the aquifer that is being studied or a planned drinking water pumping facility Upstream zones can also be used to delineate the possible locations of pollution sources when pollution has been discovered
11. in a monitoring well The registration cells are then allocated to the monitoring well locations The main difference with the determination of capture zones for wells is that the cells of interest do not necessarily contain wells or other sinks and that particles will in general not stop or be captured by the registration cells If more than one registration cell is used the output for datatypes 112141 and 112171 should therefore be evaluated carefully at different output times as particle could be moving from one registration cell to another and might appear several times in 16 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj output type 112171 i e once for each registration cell the particle has passed through 6 2 Groundwater Age The Particle Tracking module includes a facility to estimate the groundwater age When particles are introduced in the model e g in the precipitation the particle birth day is registered along with other information associated to this particle This enables the model to calculate the average age of the groundwater in each grid cell by calculating the average difference between current time and birth times for all particles located in the cell Different procedures can be used for estimation of groundwater age Below one procedure is described where particles are introduced with the infiltrating water originating from precipitat
12. E SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj immediately removed by a sink in the compartment the particle only registers the first time it enters a registration cell 8 REFERENCES Abbott M B J C Bathurst J A Cunge P E O Conell and J Rasmusson 1986a An introduction to the European Hydrological System Systeme Hydrologique Europeen SHE 1 History and philosophy of a physically based distributed modeling system Journal of Hydrology 87 45 59 Abbott M B J C Bathurst J A Cunge P E O Conell and J Rasmusson 1986b An introduction to the European Hydrological System Systeme Hydrologique Europeen SHE 2 Structure of a physically based distributed modeling system Journal of Hydrology 87 61 77 Foster S S D and A C Skinner 1995 Groundwater protection The science and practice of land surface zoning ATV Denmark Huyakorn P S and G F Pinder 1983 Computational Methods in Subsurface Flow Academic Press Inc New York Kitanidis P K 1994 Particle tracking equations for the solution of the advection dispersion equation with variable coefficients Water Resource Research vol 30 no 11 3223 3227 Kinzelbach W and G Uffink 1991 The random walk method and extensions in groundwater modelling in Transport Processes in Porous media edited by J Bear and M Y Corapcioglu pp 761 787 Kluwer Academic Norwell Ma
13. UTM XYunit so 2 1 0 0 Registration zone 2 1000 Registration zone 2 1000 Registration zone 2 0 Registration zone 3 Q Registration zone 0 0 0 0 Figure 3a Example of Registration Zone Code file using Polygons to delineate Registration Zones See Appendix A 5 of the Pre and Post processing Module User Guide for Explanation of the dig file Filetype Datatype Verno 32 0 540 Textline Registration zone code file UTM XYunit i 2 3 500 0 500 0 1 Registration zone cell 1 3 550 0 350 0 1 Registration zone cell 2 Figure 3b Example of Registration Zone Code File using Points to identify Registration Zones If the user turns on the PT module execution by using the input from the transport set up file all input for PT will be read from the transport set up file 42 Alternative Procedure Alternatively the PT input can be specified in a separate file named lt setupname gt ptinp and located in the AD subdirectory Please notice that this procedure was kept as an alternative for reasons of backward compatibility and hence not the recommended procedure An example of the PT input in this separate file is presented in The input is similar to the input at the bottom of the AD input file except for the input for the registration cells which is not read from a dig file in this case In the separate file the user has to specify the number of registration compartments as well as the location of each of the regis
14. arily removed by the well There could be other sinks in the compartment or the well could be a too weak sink allowing the particle s to slip away to neighbouring cells So certain cells might appear as belonging to the capture zone while no particles from the cell actually were take out by the well The opposite is also possible in which compartments which have contributed one or more particles to the compartment containing the well do not appear in the capture zone output This occurs when not all particles from a certain cell end up in the same cell as the one containing the well of interest If they instead move to a different registration cell the compartment from which the particle originated might appear in output data type 211141 as belonging to a different capture zone It is in general therefore not recommended to use datatype 211141 for delineating the capture zones for wells but to use datatype 211174 instead If the model only contains a single well there is also no need for registration cells when delineating capture zones for wells In general however registration cell information is needed to distinguish the different wells and a registration cell dig file is needed with one registration code per well field The procedure for delineating the capture zones for wells is then a Edit the Particle Tracking part of the Transport Setup File lt setupname gt tsf see 1 Enable Particle Tracking by setting PARTICLE TRACKING true
15. be stored with the same time interval as the other results in the water movement calculations 2 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj 2 Prepare the AD input file lt setupname gt tsf using the solute transport menu system menu T 1 T 3 This part covers entering information on initial concentrations boundary conditions dispersion coefficients and simulation parameters time step length and print out times 3 Prepare the particle tracking input It is recommended to include the PT input in the bottom of the AD input file lt setupname gt tsf by using a text editor So far no menu system has been developed for the specific PT input Alternatively a separate file that has to be named lt setupname gt ptinp could contain the specific PT input This file must be located in a subdirectory called AD First the program will search for PT input at the bottom of the AD input file If the input is not found a second search for a separate input file will be performed in the AD subdirectory Run the model from the solute transport menu system menu T 4 Retrieve model results using the output retrieval program menu U 9 ve 4 CREATING INPUT FOR THE PARTICLE TRACKING MODULE 4 1 Recommended Procedure Input for PT should be included at the bottom of the transport setup file setupname tsf In an example of PT input at the bottom of the transp
16. btained using the ground water model MIKE SHE WM These velocities are used by the particle model to calculate u X t using linear interpolation for the spatial interpolation in three directions in the grid cells For time integration simple Eulerian integration is used The numerical input used by the water movement calculations MIKE SHE WM Abbott et al 1986a 1986b is reused in the particle model as control volumes see e g equation 7 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 DHI Software 2000 20 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj there is only vertical movement in the dry layers The different handling of the INITSPEC 2 option was introduced to allow for a similar behaviour of PT compared to the original finite difference AD solution In the current version of PT the vertical position of particles is corrected for changes in compartment thickness when a particle moves horizontally from one compartment to the next The correction uses the relative vertical location at the old location to determine the new vertical location Zoa X TOP ep 7 B
17. d the transient or steady state flow field for the particle tracking calculations Select grid values Click on the display data types button A list of available data types will be displayed including particle tracking results e Enter the plot number the data type the filename the layer number and the plot type The filename is the name of the transport result file lt setupname gt trf Which will be located in the folder sheres VAD e Click on the plot layout button and specify the output date It is not possible to step through available storage times use the AD Output Retrieval utility menu U 9 to determine output times e Specify all other input parameters as usual and Click on the Apply button and click on the read and plot button in the menu G 1 PT can also store results to a separate binary output file named pt bin when the LPTBIN option is set true T This binary file contains the particle locations at every SZ time step and can be used to calculate detailed flow lines for individual particles The structure of the pt bin file is shown in Possible sink type codes used in pt bin are listed in Notice The pt bin file can be very large and its creation slows down the PT calculation For each SZ time step 1 line with 4 byte signed integer number of particles 4 byte signed real time of output followed by number of particle lines with each line containing 4 byte signed in
18. e input from the separate file lt setupname gt ptinp is not read in this case Notice There is no input for vertical coordinate correction in the old ouput format The correction will therefore always be active when using the old input format 5 RETRIEVING VIEWING AND PLOTTING THE RESULTS The output of the PT calculations consists of a transport print file lt setupname gt tpf and a binary transport result file lt setupname gt trf Optionally the program can also write output to a binary file called pt bin The output in the transport print file tpf is intended for logging program execution For PT it presents the particle balance during the calculation and some additional information on memory usage Results from a particle tracking simulation in the transport result file trf can be retrieved by the AD Output Retrieval utility menu U 9 as maps of different parameters and viewed in the Graphical editor menu DHI Software 2000 8 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj G 2 as normal T2 data or plotted directly by the Graphical Presentation tool menu G 1 For retrieval of results follow the specifications for the AD Output Retrieval utility menu U 9 i e select transport result file lt setupname gt trf select output type SZ data and select data type other data type The latter specification is not a usual data type but it is p
19. hould change this line to PARTICLE TRACKING F Notice The line should be inserted below the End of File line to stress PT computation is an external option see the example in Figure 1 Alternatively a possibility in which an environment variable is used is retained in this version for backward compatibility with previous versions of PT The environment variable is set by editing the file shedir sheenv bat to activate the PT module The line containing set ptcalc off must be changed to set ptcalc on The PT module will then be executed instead of the finite difference solution of the advection dispersion equation If the finite difference solver i e the advection dispersion module is preferred the sheenv bat file should be changed back to its original appearance Notice By setting the environment variable TRUE the PT module will always be executed regardless of the input in the transport set up file the PT module is used when either the environment variable or the input in the transport set up file or both are set TRUE To avoid any confusion it is not advised to use the environment variable with this version of the PT module 3 RUNNING THE PARTICLE TRACKING MODULE DHI Software 2000 The general procedure for particle tracking simulations is 1 Simulate a transient or steady state ground water velocity field using the MIKE SHE water movement module WM menu F 1 F 4 Notice that PT requires the flow results to
20. ink type code if the particle has been removed from SZ in a cell which is not a registration cell There is one file for each of the possible sink codes and each layer 112171 particle that have reached active cells which are registration zone cells 112172 particles that have gone to a river sink 112173 particles that have gone to a drain sink 112174 particles that have gone to a well sink DHI Software 2000 MIKE SHE WQ Particle Tracking Module 9 DHI Water amp Environment DHI Institut for Vand amp Milj Table 2 112175 particles that have gone to the unsaturated zone 112176 particle that have gone to all other sinks Possible codes used for sinks are listed in The registration period is from the specified start date in the AD output retrieval menu menu U 9 until the end of the calculation Each line contains the values e birth x coordinate e birth y coordinate registration cell number or negative value of sink type travel time day Notice that data type 112171 can only contain registration cell numbers as the particles in an active cell will only be registered if that cell is a registration cell Sink Codes for the AD Output Retrieval Data Type 11217i Zone Value of registration Sink type 3 13 River Drain Well Exchange with UZ Constant concentration cell boundary Constant concentration cell internal source e 112187 with i 1 6
21. ion In this case the groundwater age will represent the transport time from the soil surface to the groundwater storage and thus serve as information of the groundwater storage vulnerability 6 2 1 Determination of ground water age step by step a Edit the Particle Tracking part of the Transport Setup File lt setupname gt tsf see 1 Enable Particle Tracking by setting PARTICLE TRACKING true 2 Specify any positive number for the particle mass particle mass is not used for determination of groundwater age 3 Initial number of particles in the groundwater choose one of the options 1 No initial particles will be present in the groundwater by setting INITSPEC 0 Recommended ii The initial number of particles in the groundwater will be specified in the AD menu T 2 1 by setting INITSPEC 1 4 Disable the extended print to the binary file by setting LPTBIN false 5 Finally no specification of a regzone file is necessary no registration zones are required for the groundwater age determination 6 Save the Transport Setup File b From the AD menu do as follows 1 From menu T 1 select the Flow Result File lt setupname gt frf which will provide the transient or steady state flow field 2 From menu T 1 1 specify porosity DHI Software 2000 MIKE SHE WQ Particle Tracking Module 17 DHI Water amp Environment DHI Institut for Vand amp Milj 3 4 5 7 8 9 10
22. n or SZ or from boundary or internal constant concentration cells Particles leave SZ when they arrive at a boundary or an internal constant concentration cell or when they go to a sink Possible sinks in the Particle Tracking are wells rivers drains and exchange with the unsaturated zone UZ All particles are assigned a mass which means that a number of particles within a specific volume corresponds to a solute concentration The Particle Tracking module can therefore be used for solute transport simulations and is in some cases superior to the conventional numerical solution of the advection dispersion equation since numerical dispersion is negligible However it is expected that the module will be used mostly for delineation of abstraction well capture zones and upstream zones and for determination of groundwater age and solute transport times which are some of the features the particle tracking module is offering 2 ACTIVATING THE MIKE SHE PARTICLE TRACKING MODULE The PT module can be activated in two ways by input in the transport setup file lt setupname gt tsf or by setting an environment variable The recommended way to turn on PT is by adding the following line to the end of the transport setup file lt setupname gt tsf PARTICLE TRACKING T DHI Software 2000 MIKE SHE WQ Particle Tracking Module 1 DHI Water amp Environment DHI Institut for Vand amp Milj To turn off the Particle Tracking the user s
23. ode when the cell is a registration cell 2 Travel times of particles datatypes 11218 i 1 6 For each calculation layer the travel times of all particles that have gone to a certain sink The correspondence between the sink code and the data types is listed in table 5 Table 5 Possible Datatypes and corresponding Sink Codes datatype sinkcode meaning 112181 no active cell particles are only registered here if they arrive in an active cell that is at the same time a registration cell 112182 particles gone to rivers 112183 3 particles gone to drains 112184 4 particles gone to wells 112185 5 particles gone to the unsaturated zone 112186 7 13 particles gone to all other sinks DHI Software 2000 The next chapter highlights the possibilities and caveats of using the module for delineating capture zones for wells which is probably the most common application After this we will shortly describe a possible alternative use of the capture zone concept in finding upstream zones 14 DHI Water amp Environment DHI Institut for Vand amp Milj MIKE SHE WQ Particle Tracking Module 6 1 1 Delineation of capture zones for wells step by step As pointed out in the previous chapter there are certain limitations to using datatype 211141 to delineate capture zones A first observation is that particles entering a registration cell containing a well are not necess
24. ort setup file is given Important notice Input is included by editing the transport setup file manually in a text editor The input should be inserted at the very end of the file i e below the End of File line A description of the input is given in END OFFILE PARTICLE TRACKING T PARTICLE MASS 10 0 INITSPEC 1 1 LPTBIN F REGZONEFILE DIGFILES regzone dig VERTICAL CORRECTION 1 Figure 1 Example of Input at the Bottom of the Transport Set up File e PARTICLE TRACKING set TRUE enables the particle tracking set FALSE disables the particle tracking and enables the AD solution DHI Software 2000 MIKE SHE WQ Particle Tracking Module 3 DHI Water amp Environment DHI Institut for Vand amp Milj DHI Software 2000 PARTICLE MASS The particle mass is intended for conversion of particle counts number of particles to concentration INITSPEC This number is used to specify how the initialisation of the number of particles for the compartments has to be done The different possible values that can be used for INITSPEC are listed in In case of a positive or zero INITSPEC there will be a constant number of particles all over the domain In case of a negative INITSPEC the user can distribute the number of particles INITSPEC 1 or the concentration INITSPEC 2 and 3 by specifying the distribution in T2 files for each layer in the solute transport menu system menu T 2 see The particles a
25. ossible to get a list of applicable numbers to be specified for other data types by clicking the right mouse button in the edit field e 112111 e 112121 e 112131 e 112141 e 112151 e 112161 T2 file with the number of particles in each grid cell for the layer T2 file with the average age of the particles in each grid cell for the layer T2 file with the number of registered particles this is the number of particles that have moved to a compartment which is a registration cell from the compartments in the layer T2 file with the capture zones This is the registration cell number of the registration cell to which a particle which started from the compartment in the layer has most recently moved to Notice that the value can change if particles from the cell move through several registration zones and or not all particles from the cell arrive in the same registration cell T2 file with the average transport times to the nearest registration cell from each compartment in the layer If no particles from that cell have entered a registration cell yet thevalue is set to the delete value Dig file with the coordinates of current particle locations Each line contains the values 03 x coordinate y coordinate e z coordinate e layer number e 112177 with i 2 1 6 Dig files with the birth locations of particles and the registration cell number of registered particles or the negative value of the s
26. ottom Bottom ey Znew new Top a 7 Bottom where old indicates the previous compartment and new the current compartment The correction is for now only applied when moving horizontally from one compartment to the other i e there is no interpolation of layer thickness during the movement within a single compartment This results in sudden changes in the vertical location at compartment boundaries In this version of PT the user can use different sinks and sources to respectively remove or add particles in certain model compartments Possible sinks are 1 aconstant concentration boundary receiving particles 2 a well 3 ariver 4 a drain connected to a river or the boundary 5 water movement to the unsaturated zone 6 compartment containing a constant concentration source that is setting the compartment concentration to a lower concentration value than the actual concentration Possible sources are 1 a constant concentration boundary from which particles are removed 2 solute concentration of the precipitation 3 a source in the saturated zone with a specified mass rate 4 compartment containing a constant concentration source that is setting the compartment concentration to a higher concentration value than the actual concentration PT only calculates particle movement in the saturated zone however the volume of water removed by the wells rivers drains and the unsaturated zone is known This volume of wate
27. r is used to calculate the number of particles that are removed by each of the sinks using the formula DHI Software 2000 MIKE SHE WQ Particle Tracking Module 21 DHI Water amp Environment DHI Institut for Vand amp Milj DHI Software 2000 V n nX x sink 7 10 V ink V ink Ve with n number of particles removed to sink i n number of particles in the compartment Vi volume of water exchanged with sink i Vsink Volume of water exchanged with all sinks Vio volume of water in the compartment Equation 7 10 will calculate the number of particles which should be removed by the sink at that time step This is however not necessarily a whole number of particles PT takes care of this by 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 assignment the next particle will then go to one of the other sinks The constant concentration sources and sinks at boundaries or inside the model domain are handled by calculating the particle number that corresponds to the concentration and truncating this value to a whole number Fo
28. r the mass flux source and the precipitation source the concentration is again converted to a particle number 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 can not only appear as sinks that remove particles to rivers or to the boundary out of the model domain Drains can also transfer particles internally in SZ If this occurs the particles are moved from one compartment to another by the drain Notice that there is no time lag in this process To enable the model to trace the particles calculate transport times capture zones groundwater 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 coordinates of birth When particles enter sinks or are introduced into the model domain by a source their 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 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 22 MIK
29. re initially randomly located within the compartment For option 2 they are only distributed over the saturated part of the compartment For the other values of INITSPEC they are located anywhere between the bottom and the top of the compartment LPTBIN set TRUE detailed output to an optional binary file pt bin will be performed The pt bin file contains output for all particles at each SZ time step see Chapter Bjfor details Important warning The binary file can be huge i e maybe more than 1 Gb Check harddisk space before enabling this option VERTICAL CORRECTION a new item in this version of PT is correction of the vertical particle coordinate when moving between compartments with changing thickness This option is by default on and this line can also be omitted To turn the option of this line should be included and the value should be set to 0 4 DHI Water amp Environment DHI Institut for Vand amp Milj MIKE SHE WQ Particle Tracking Module MShe ojx Close Help menu T 2 1 SZ INITIAL CONDITIONS AND SOURCES Current species INITIAL CONCENTRATION Lower Layer Concentration MAPS Particles T2 v Insert vw Delete ed o Up EE Y Down Select T2 file SOURCE STRENGTH Loc no Time series value DEE no ce ues Select TO file Figure 2 Example of Specification of the Distribution of Particles for INITSPEC 1 in T2 files for each Layer in the Solute Transport Menu Sy
30. ss Thompson A F B E G Vomvoris and L W Gelhar 1987 Numerical Simulation of Solute Transport In Randomly Heterogeneous Porous Media Motivation Model Development and Application Lawrence Livermore National Laboratory Thompson A F B and D E Dougherty 1998 On the use of particle tracking methods for solute transport in porous media in Computational Methods in Water Resources vol 2 Numerical for Transport and Hydrologic Processes edited by M Celia L Ferrand C Brebbia W Gray and G Pinder Elsevier New York Uffink G J M 1988 Modelling of solute transport with the random walk method in Groundwater Flow and Quality Modelling edited by DHI Software 2000 MIKE SHE WQ Particle Tracking Module 23 DHI Water amp Environment DHI Institut for Vand amp Milj E Custodio A Gurgui and J P Lobo Ferreira pp 247 265 D Reidel Hingham Mass USA DHI Software 2000 24 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj
31. stem Menu T 2 DHI Software 2000 MIKE SHE WQ Particle Tracking Module 5 DHI Water amp Environment DHI Institut for Vand amp Miljo Table 1 Possible Values for INITSPEC INITSPEC Meaning lt 3 An error will be generated 3 An initial particle concentration in the groundwater has to be specified in the AD menu T 2 1 This concentration will be converted to a number of particles by using the particle mass and the saturated volume of each of the compartments If the resulting number of particles is not an integer a truncation to nearest integer is performed The particle are distributed randomly over the whole compartment height 2 An initial particle concentration in the groundwater has to be specified in the AD menu T 2 1 This concentration will be converted to a number of particles by using the particle mass and the saturated volume of each of the compartments If the resulting number of particles is not an integer a truncation to nearest integer is performed The particle are distributed randomly over the saturated part of the compartment 1 An initial number of particles in the groundwater has to be specified in the AD menu T 2 1 The particle are distributed randomly over the whole compartment height 20 INITSPEC constitutes the number of particles that will be initially present in each of the compartments of the model domain The particle are distributed randomly over the whole compartment height
32. teger particle ID 4 byte signed real X coordinate 4 byte signed real y coordinate 4 byte signed real z coordinate 1 byte signed integer particle sink type Figure 5 Structure of the pt bin File DHI Software 2000 MIKE SHE WQ Particle Tracking Module 11 DHI Water amp Environment DHI Institut for Vand amp Milj Table 3 Possible Sink Codes in the pt bin File Sink code Sink type 0 Unknown 1 Active cell 2 River sink 3 Drain sink 4 Well sink 5 Exchange with UZ sink 6 Constant concentration boundary source 7 Constant concentration boundary sink 9 Zero flux boundary 10 Precipitation source 12 Constant concentration cell internal SZ source 13 Constant concentration cell internal SZ sink DHI Software 2000 12 MIKE SHE WQ Particle Tracking Module DHI Water amp Environment DHI Institut for Vand amp Milj 6 PARTICLE TRACKING APPLICATIONS Using the PT module for delineation of capture zones for determination of upstream zones and for groundwater age determination are expected to be among the most popular applications Thus it has been found useful to explain the procedures for these features in more detail 6 1 Capture Zones A capture zone is defined as the area from which the water originates that eventually arrives in a certain point In terms of the model a capture zone then corresponds to the ensemble of cells containing particles that
33. tration cell compartments The location can be specified using row number column number from the model grid set up option 1 or x y co ordinates option 2 Please recall that this file was kept as an alternative for reasons of backward compatibility The text in the file reflects the fact that in previous versions a more restricted form of registration cells called capture zones was used The number of registration cells is therefore called NCAP in this file DHI Software 2000 MIKE SHE WQ Particle Tracking Module 7 DHI Water amp Environment DHI Institut for Vand amp Milj INPUT FILE FOR PARTICLE TRACKING MODULE particle inp PARTICLE MASS gram Number of capture zones influence zones to estimate Number of init part in each grid 0 for conc is used Output to pt bin T F The following lines specifies the location of grid cells for which data on particles entering the cells is always stored The two options for specifying these cells Option 1 option grid layer grid column grid row Option 2 option grid layer x coordinate y coordinate option 1 or 2 layer column x coord row y coord 1 6 20 20 regzonel Figure 4 Example of Input as a separate Input File AD lt setupname gt ptinp Notice If the user turns on the PT module execution by using the input from the transport set up file all input for PT will be read from the transport set up file This implies that th
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