AquiMod User Manual (v1.0) - NERC Open Research Archive
Contents
1. 1995 Report No 126 Hydrology of soil types a hydrologically based classification of the soils of the United Kingdom Wallingford UK Institute of Hydrology 342. Range variable type n Maximum number of time steps taken for soil drainage to reach the gt 0 integer groundwater k Weibull shape parameter 1 7 float A Weibull scale parameter gt 0 float SATURATED ZONE COMPONENT PARAMETERS Q3K3S1 Parameter units Description Recommend Range variable type Ax m Catchment length gt 0 float K md Top layer hydraulic conductivity 10 10 float K md Middle layer hydraulic conductivity 10 10 float K md Bottom layer hydraulic conductivity 10 10 float S Aquifer storage coefficient 0 1 float Z3 m asl Top outlet elevation float Z2 m asl Middle outlet elevation float z m asl Bottom outlet elevation float a Forces the hydraulic conductivity to 0 1 bool increase with elevation when set to 1 31 OR 14 007 Appendix 2 List of output variables produced in time series files for each module component SOIL ZONE COMPONENT OUTPUT VARIABLES FAO Variable units Description Runoff mm d AET mm d SMD mm Soil Drainage mm d Surface runoff Actual evapotranspiration from soil Soil moisture deficit Soil drainage to unsaturated zone UNSATURATED ZONE COMPONENT OUTPUT VARIABLES Weibull Variable units Description Recharge mm d Recharge to the saturated zone SATURATED ZONE COMPONENT OUTPUT VARIABLES Q3K3S1 Variable units Descriptio
3. Table 5 7 Example of fit_calib out file produced by AquiMod using the NSE objective function 20 Table 5 8 Example of Q3K3S1_TimeSeries1 out from an evaluation TUN ennen 21 111 OR 14 007 Summary This user manual describes AquiMod a simple lumped groundwater level simulation model It details the mathematical structure of the model and provides some guidance for configuring and running the software on a Windows PC All examples shown were undertaken on a computer running Windows 7 and as such some of the steps may differ when using a different version of the Windows operating system iv OR 14 007 1 Overview AquiMod is a lumped parameter computer model that has been developed to simulate groundwater level time series at observation boreholes in aquifers by linking simple hydrological algorithms that model soil drainage the transfer of water through the unsaturated zone and groundwater flow It runs on a Windows PC through the command prompt and is configured using a series of text files The simple structure of AquiMod makes it easy to use in comparison to more complex physically based distributed models and therefore should be accessible to those users who are new to the field of groundwater hydrological modelling It uses conceptual modelling approaches that are in line with general hydrological process understanding and has been used in the past to teach hydrological modelling concepts to Earth Science undergraduates The main
4. a function of potential evapotranspiration PET L and the SMD Figure 3 1b OR 14 007 aer per 4V O if SMD gt RAW 7 Faw RAW AET PET SMD lt RAW a AET 0 SMD gt TAW 4 When the soil zone becomes saturated any rainfall in excess of the evaporative demand of the vegetation becomes excess water EXW This excess water is then split between soil drainage and surface runoff The proportion of the excess water EXW that drains to the unsaturated zone is SD BFI EXW 5 where SD is the soil drainage and BFI is the baseflow index which defines the average proportion of stream flow that a river receives from groundwater discharge Surface runoff is then calculated as the remainder of the excess water PPTN AET a t b EXW 0 AET PET l RAW RAW Q TAW 5 SMD TAW SD BFI EXW Figure 3 1 a FAO soil zone component conceptualised as a bucket with a finite capacity and b the change in ratio of AET to PET with SMD as described by equation 4 OR 14 007 3 2 UNSATURATED ZONE MODULE Currently there is only one unsaturated zone component available in the AquiMod software Table 3 2 Table 3 2 Summary of unsaturated zone module components ID Name Description 1 Weibull Drainage from the soil is attenuated through the unsaturated zone using a Weibull distribution transfer function 3 2 1 Weibull Recharge is distributed over a number of time steps n and the proportion of soil drai
5. as Microsoft Excel However plotting the full range of simulations is often faster using a scripting language Figure 6 9 has been produced using MATLAB and shows the 90 bands of all the simulations in blue calibration sequence and red evaluation sequence against the observations black dots 90 MEA Calibration range ESS Evaluation range Mean simulation Observations 80 a fez o o Groundwater level m asl EN 30 20 l l T T l l T T l l l l 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Figure 6 9 Range of simulations shown in blue calibration sequence and red evaluation sequence with the mean simulation solid black and observations black dots 6 3 DEACTIVATING MODULES AND USING OTHER COMPONENTS You may select any combination of the available module components when using AquiMod You may also deactivate modules entirely using the ID 0 in Input txt if you only wish to consider part of the hydrological system This may be useful for example if a boundary condition flux is known and therefore does not need to be simulated or if part of the hydrological system is not deemed to be important for a particular application If the soil zone is deactivated evapotranspiration is assumed to be zero and rainfall passes directly to the unsaturated zone as soil drainage If the unsaturated zone
6. information on the output variables produced for each module component see Appendix 2 A corresponding fit_eval out file is also produced which returns the objective function score for each parameter set The structure of this file is identical to that for a calibration run Table 5 6 Table 5 8 Example of Q3K3S1_TimeSeries1 out from an evaluation run Line File text Description number 1 Day Month Year Q3 m3 d Q2 m3 d Q1 m3 d GWL m Header Line 2 31 1 191 0 0 0 70 665 Variable values 3 28 2 1961 4 82748 5 21203 0 248902 61 1048 4 31 3 1961 0 893412 4 06564 0 219899 55 6219 5 30 4 1961 0 0516189 3 40817 0 203265 53 9034 6 31 5 1961 4 61944e 006 3 20209 0 198052 50 2362 21 OR 14 007 6 Tutorials This section provides a series of step by step tutorials that can be used to familiarise yourself with the AquiMod software All of the examples shown use the model in the CHexample folder If you do not have this already follow the instructions in section 2 6 1 HOW TO PERFORM A CALIBRATION RUN This tutorial provides instructions to calibrate an AquiMod model for an observation borehole catchment in the United Kingdom You will configure the Observations txt and Input txt files and learn about the calibration input files You will then run a Monte Carlo calibration procedure and examine the model outputs 6 1 1 The Chilgrove House observation borehole The Chilgrove House observation borehole is located in the Cret
7. is deactivated soil drainage is allowed to pass instantaneously the saturated zone If both the soil and unsaturated zone are deactivated the rainfall input essentially becomes a recharge input to the saturated 29 OR 14 007 zone If the saturated zone is deactivated groundwater recharge discharges instantaneously out of the model domain As a final exercise experiment with deactivating different modules in the AquiMod structure You should find for the Chilgrove House observation borehole catchment that efficient simulations of groundwater levels can still be reproduced without the inclusion of the unsaturated zone component You may also wish to experiment with using other components This can be done simply by changing the options in Input txt and the associated input files For this it is recommended to use the template files available on the AquiMod website 30 OR 14 007 Appendix 1 List of component parameters and recommend range of values to be used SOIL ZONE COMPONENT PARAMETERS FAO Parameter units Description Recommend Range variable type BFI Catchment baseflow index 0 1 float FC Field capacity of the soil 0 1 float WP Wilting point of the soil 0 1 float Zr mm Maximum rooting depth of catchment vegetation 100 3000 float p Depletion factor of catchment vegetation 0 1 float UNSATURATED ZONE COMPONENT PARAMETERS Weibull Parameter units Description Recommend
8. months is sufficient for this observation borehole catchment Acceptable model threshold deciding upon a suitable value for this will depend on the type of application and personal preferences For this tutorial an arbitrary value of 0 8 will be used Maximum number of acceptable models again defining this value is likely to depend on the proposed application For this tutorial you will only consider the most efficient 1000 models assuming 1000 exceed the acceptable model threshold Write model output files in calibration mode the output files will contain the parameter sets of the most efficient Monte Carlo simulations You will need this information later on so set all of these to Y 23 OR 14 007 laf CACHexample Input txt Notepad File Edit Search View Encoding Language Settings Macro Run Plugins Window DAR slee dll 1 Sal O 1 Component IDs EAA Simulation mode c Number of runs 100000 Objective function 1 Spin up period 6 Acceptable model threshold calibration only 0 8 Maximum number of acceptable models calibration only 1000 Write model output files Y Y length 267 lines 23 Ln 23 Col 6 Sel 0 Dos Windows ANSI Figure 6 3 Configured Input txt file for the Chilgrove House calibration run 6 1 4 Calibration input files For this example the calibration input files have been pre configured so that a total of 8 of the 16 parameters will be calibrated whi
9. portion of the simulation when calculating the chosen objective function The length of this period is likely to depend on the choice of model structure and parameters Past experience has shown that the unsaturated zone component often has the longest memory of the three components in AquiMod For example when using the Weibull unsaturated zone component the n parameter which defines the number of time steps over which recharge is spread can also be used to define the spin up period see section 6 1 for further information on defining the spin up period e Acceptable model threshold This option is only applicable when running AquiMod in the Monte Carlo calibration mode It defines the objective function threshold that must be reached for the parameter set of the simulation to be stored and output 17 OR 14 007 Maximum number of acceptable models This option is only applicable when running AquiMod in the Monte Carlo calibration mode It defines the maximum number of parameter sets that exceed the acceptable threshold that will be output Note that AquiMod uses the quick sort algorithm to sort the Monte Carlo runs by objective function Simulation time may increase if large numbers of acceptable parameter sets are stored Write model output files Here the user can specify if they wish output files to be written for each model component When running in calibration mode a single file is output for each component In eval
10. run esseere 28 Figure 6 8 Command prompt view when running AquiMod in evaluation mode 29 Figure 6 9 Range of simulations shown in blue calibration sequence and red evaluation sequence with the mean simulation solid black and observations black dots 29 11 OR 14 007 TABLES Table 1 1 Considerations and potential limitations when applying AquiMod for groundwater level simulaties eere an eed 1 Table 3 1 Summary of soil zone module components annae ev enneevennervenneevenvervenveevenne 6 Table 3 2 Summary of unsaturated zone module components naan enne evenneeeenverennn 8 Table 3 3 Summary of saturated zone module components onno onneevenneerennereenveerenne 9 Table 4 1 Objective functions available in AquiMod for a simulation sequence with n time steps calculated using the observed ho and modelled hm groundwater levels 14 Table 5 1 Example Observations DEE ane eene eeen ene 16 Table 5 2 Imposing groundwater levels in the Observations txt file eneen 17 Table 5 3 Example dnp ts xt MIE taenaria dead E 18 Table 5 4 Example of the FAO_calib txt calibration input file format The field capacity line 2 is fixed while the root depth line 8 will change for each calibration run eee eects 19 Table 5 5 Example of FAO eval txt file svn rverrertsernsansdernetedanrsertaaadhndenensessanendestdetonnadelenaesdde 19 Table 5 6 Example of FAO_calib out file sans smets deter eee 20
11. the bottleneck in the overall simulation run time Finally it writes the output files to the Output folder and then states the total run time 25 OR 14 007 EN C Windows system32 cmd exe Lo 5 kel iC gt aquimod C CHexample Running 166666 times complete Extracting best models complete Writing output files complete Model run time 5 seconds Figure 6 5 Command prompt view when running AquiMod in calibration mode 6 1 6 Output files Navigate to the Output folder AquiMod should have produced a fit_calib out file as well as a _calib out file for each of the three module components Open the fit_calib out file to check if any acceptable models have been obtained The file should be filled with up to 1000 NSE scores You can use the fit_calib out file in conjunction with the _calib out module component files to assess the sensitivity of the parameters For example in Figure 6 6 two dotty plots have been drawn in MATLAB which indicate that the S parameter shows more sensitivity than the K3 parameter 0 95 0 95 0 94 4 0 94 0 93 0 93 0 92 4 0 92 0 91 0 91 4 NSE 0 97 NSE 0 9 0 89 0 89 0 88 0 88 0 87 0 87 0 86 0 86 0 85 7 0 85 0 2 0 3 0 4 0 5 0 6 0 7 0 8 0 9 1 5 10 15 20 25 30 S K3 Figure 6 6 Dotty plots to assess sensitivity of S left and K3 m d right parameters from the Q3K3S1 saturated zone component Plots contain 1000 acceptable models ob
12. the point of inflection zp the hydraulic conductivity is constant In the upper section above Zp the hydraulic conductivity increases linearly with elevation Subsequently the transmissivity is calculated as T K h zi 0 5 m h zp 12 where K is the hydraulic conductivity at the base of the aquifer and m is the gradient of the hydraulic conductivity profile above the point of inflection The total discharge is then calculated as before TAy 0 5Ax 13 Q h z1 12 OR 14 007 gl gt Q Hydraulic conductivity Figure 3 7 VKD saturated zone component 13 OR 14 007 4 Simulation modes AquiMod has two different simulation modes calibration and evaluation which are described below 41 CALIBRATION The calibration mode is used to determine the most efficient model structures and parameter sets for the chosen application i e those that produce groundwater level time series that best replicate available observational data In calibration mode AquiMod has an in built Monte Carlo parameter sampling algorithm that runs a specified model structure using multiple unique parameter sets up to 10 which are randomly sampled from a user defined parameter space For each parameter set the model is run and a measure of simulation efficiency is calculated by comparing the simulated groundwater level time series to available observed data Three different objective functions can be used in AquiMod
13. to determine model efficiency Table 4 1 Table 4 1 Objective functions available in AquiMod for a simulation sequence with n time steps calculated using the observed h and modelled h groundwater levels ID Name Description 1 Nash Sutcliffe Efficiency NSE n ht ht u l ICI yl NSE 1 t 1 o im 008 ho 2 Root Mean Squared Error RMSE n RMSE Y jet t 1 3 Mean Absolute Percentage Error MAPE i 4 2 EVALUATION When using the evaluation mode the user is required to specify one or more fixed parameter sets AquiMod then determines the model efficiency for each of these and also generates time series output files for each model component e g groundwater level time series for the saturated zone 14 OR 14 007 5 Model Files This section provides more details about the model files that are used to configure AquiMod as well as the output files produced by the software Most text editors are suitable for reading and editing AquiMod files although it is advantageous to use an editor that displays line numbers as these are used in the file tables in this section Examples include Notepad and PSPad both of which are freely available to download from the internet 5 1 GENERAL FILE AND FOLDER STRUCTURE All of the information required to configure and run AquiMod is stored in a series of text files within a defined folder structure Figure 5 1 The Observations txt file contains all of th
14. 003 2005 A A a DD a Groundwater level m asl a EN o w a 30 T T T T T T T T T T T T T T T T T T T 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2003 2005 Figure 6 2 Observed rainfall PET top and groundwater level data bottom for the Chilgrove House observation borehole catchment 6 1 2 Observations txt First you will calibrate the model against the first half of observed groundwater data between January 1961 and June 1983 This half of the data can be found in ObsCalib txt Copy and paste this in Observations txt Note that there is no significant groundwater abstraction in the catchment and as such these rates have been set to zero Also note that the model will run on a monthly time step 6 1 3 Input txt Next you will configure the Input txt file as shown in Figure 6 3 Open this file in a text editor Going through each option in order Component IDs you will use the FAO Weibull and Q3K3S1 module components so these should all be set to 1 Simulation mode this should be set to c to run in calibration mode Number of runs for this tutorial you will run the model 100 000 times in order to find the most efficient parameter sets Objective function you will use the NSE as the measure of model fit and so this should be set to 1 Spin up period a spin up period of 6 time steps
15. 3 Evaluation input files The file structure of the _eval txt input files is exactly the same as the output files from the calibration mode Since you will evaluate the calibrated parameter sets these files can simply be moved to the Evaluation folder and renamed accordingly For example Output Q3K3S1_calib out should be moved and renamed to Evaluation Q3K3S1_eval txt 6 2 4 Running AquiMod in evaluation mode Having configured all of the required input files AquiMod is now ready to run as shown in section 2 2 Run AquiMod in the command prompt This should return similar messages as the calibration run Figure 6 8 Note that the runtime is longer for these evaluation runs even though far fewer runs have been performed than the 100 000 in the previous tutorial This is because AquiMod has to write a time series file for each run As such when performing large numbers of evaluation runs and outputting the results runtime can increase considerably 28 OR 14 007 ES C Windows system32 cmd exe C gt aquimod C CHexample Running 1666 times complete Model run time 34 seconds Figure 6 8 Command prompt view when running AquiMod in evaluation mode 6 2 5 Output files After running AquiMod in evaluation mode it should have produced a fit_eval out file in the Output folder as well as time series files for each parameter set for the Q3K3S1 module component Individual time series can easily be plotted in applications such
16. a space The CHexample folder contains an example model build that is ready to run In the command prompt type aquimod followed by the location of the CHexample folder as shown in Figure 2 4 EN C Windows system32 cmd exe gt aquimod c chexample Running 1 times complete Model run time seconds Figure 2 4 Running AquiMod through the command prompt Notice that AquiMod provides output messages to indicate that the model run has completed If you navigate to the Output folder you ll notice a series of files with the out extension These are output files produced by AquiMod They are text files that can be viewed in your text editor OR 14 007 3 Modules AquiMod has three modules that represent the soil unsaturated and saturated zone hydrology Each module has been designed so that it can incorporate a number of possible structures components each based on a different conceptual representation of the process being considered but all of which adhere to the same generalised structure outlined in section 1 2 Each component uses one or more parameters which can be modified to change the behaviour of the model These parameters and the mathematical algorithms that AquiMod employs are described below Please note also that all component parameters and recommended calibration ranges are listed in Appendix 1 3 1 SOIL ZONE MODULE Currently there is only one soil zone component available in the AquiMod software Tabl
17. aceous Chalk aquifer in the south of the United Kingdom Figure 6 1 It has groundwater level records from 1836 and is one of the longest groundwater level time series in the world Situated in the unconfined Seaford Chalk formation the hydrograph displays a typical sinusoidal response generated by the seasonal recharge signal typical of unconfined aquifers in the UK More information on the Chilgrove House observation borehole can be found on the British Geological Survey web site at http www bgs ac uk research groundwater datainfo levels sites ChilgroveHouse html In this tutorial you will focus on a 45 year time series of groundwater level data between January 1961 and December 2005 over which reliable rainfall and PET estimates are also available Figure 6 2 Key Eik Lower Greensand Chalk Formations Group Upper Greensand Groundwater Formation Catchment Lambeth Group River N London Clay O Borehole TTS Formation Sie Y Ae 1 e Sina 115 CHILGROVE HOUSE NS Figure 6 1 Location of Chilgrove House observation borehole along with geological setting and nearby river network 22 OR 14 007 Rate mm 1 Rainfall maanen PET JEN Y T nn ES y y EN I I I I I I T T I I I T I l 1961 1963 1965 1967 1969 1971 1973 1975 1977 1979 1981 1983 1985 1987 1989 1991 1993 1995 1997 1999 2001 2
18. action Saturated zone Groundwate discharge Figure 1 1 Generalised structure of AquiMod OR 14 007 2 Getting started 2 1 INSTALLATION Before starting you ll need to download the AquiMod software which is available directly from the British Geological Survey website at http www bgs ac uk research environmentalmodelling aquimod The download package includes the AquiMod executable located within the AquiMod folder an example model build which is located within the CHexample folder and a series of template files located in the Template folder which can be used when constructing a new model If this is the first time you ve used this software we recommend that you copy all of the folders to your hard disk as some of the files are required for the Tutorials section Next you must add the AquiMod folder to the Windows Path environment variable this makes it easier to run AquiMod from the command line For this do the following e From the Start menu right click Computer and select Properties from the dropdown menu e Select Advanced System Settings in the left column This will open the System Properties windows Figure 2 1 e Under the Advanced tab click the Environment Variables button System Properties Computer Name Hardware Advanced System Protection Remote You must be logged on as an Administrator to make most of these changes Performance Visual effects processor scheduling memo
19. as its own discharge outlet Figure 3 4 The deepest layer represents groundwater which flows out of the catchment via subsurface flow paths The upper outlet is a lumped representation of surface discharge points in the catchment including rivers and springs It may flow intermittently if the groundwater head falls below the outlet elevation As with the Q3K3S1 component the hydraulic conductivity can be forced to increase with elevation when using randomly sampled parameter sets by specifying the a parameter Zi Figure 3 4 Q2K2S1 saturated zone component 3 3 3 Q1K1S1 This component employs the same structure according to equations 8 11 however here only one layer is defined with a single discharge outlet Figure 3 5 Zi Figure 3 5 Q1K1S1 saturated zone component 11 OR 14 007 3 3 4 QITIS1 Like the QIK1S1 saturated zone component this component also employs a single outlet Figure 3 6 However the transmissivity is assumed to be fixed and independent of the hydraulic head h This is equivalent to a confined aquifer representation Zi Figure 3 6 Q1T1S1 saturated zone component 3 35 VKD As an alternative to using specified layers and outlets the user can also implement a variable conductivity with depth VKD profile Here a cocktail glass representation is can be employed which has two distinct sections Figure 3 7 In the lower section between the base of the aquifer z and the elevation of
20. ax 029 2052 1963 Maclean Building Crowmarsh Gifford Wallingford OX10 SBB Tel 01491 838800 Fax 01491 692345 Geological Survey of Northern Ireland Colby House Stranmillis Court Belfast BT9 SBF Tel 028 9038 8462 Fax 028 9038 8461 www bgs ac uk gsni Parent Body Natural Environment Research Council Polaris House North Star Avenue Swindon SN2 1EU Tel 01793 411500 Fax 01793 411501 www nerc ac uk Website www bgs ac uk Shop online at www geologyshop com OR 14 007 Contents SUMMARY vereen kentenken ser rao E EESE E a a a a IE 1 A AAA A E EE E TAE EE TA TETE E EET TES Le Intended Use ratita als ta canada T AE 1 1 2 Generalised structure sassen e a a a a a a a i e a 2 ze o A O nerede dildo ssas teoer ierra badara ie del WES tall Atoms Ae ARE 3 22 Kunne AguModi nt neten 5 A RO SL Soil zone module anida iii 6 3 2 Unsaturated zone module ooccccccnononununoncncnnononanicaconononcnnonnnanacnococononononanenacococonononanens 8 3 3 gt Saturated zone modulos iia tai 9 4 Simul tion modes ssssssssorsicrsssrsrrdsonsaisesterseressr aaeeea sois es oa es a ioes s 4 A N GEIN 15O On 14 AD Val tath ON 14 S gt Model A A LO 5 1 General file and folder structure wae OOO RGR ee Gs 15 J2 put Hle Sa enekele nne Ane death Neenee dela 15 39 Output files tenten n E E de da 20 6 Tura E OR a ZD 6 1 How to perform a calibration run sssessesssesssesesseeessessessseeeseee
21. by equation 4 7 Figure 3 2 Probability distribution function of the Weibull distribution using different and k COMTE dede aaneen eee eenn 8 Figure 3 3 Q3K3S1 saturated zone COMPOM bye il 10 Figure 3 4 Q2K2S1 saturated zone component enen erder ae eae sae dende 11 Figure 3 5 OLK US saturated zone component serre rte a da 11 Figure 3 6 OITISI saturated zone component ciinvicinn dc dd a dias 12 Figure 3 7 VKD saturated zone component ii Aids 13 Figure 5 1 Folder structure of AquiMod onetzitenssonsenenetsnstaneednntsbeintnenentnietsndedennteetndesde 15 Figure 6 1 Location of Chilgrove House observation borehole along with geological setting and DEMONIO EEEE EAE EE AE E E ae E 22 Figure 6 2 Observed rainfall PET top and groundwater level data bottom for the Chilgrove House observation borehole catchment ioiscsi a bergen apseseatovatondacsedsdagsegeanseenseoaess 23 Figure 6 3 Configured Input txt file for the Chilgrove House calibration run eee eeeeeeeeees 24 Figure 6 4 Cross correlations between rainfall and de seasonalised groundwater levels 23 Figure 6 5 Command prompt view when running AquiMod in calibration mode 26 Figure 6 6 Dotty plots to assess sensitivity of S left and K3 right parameters from the Q3K3S1 saturated zone component Plots contain 1000 acceptable models obtained from the A A enkle eene Ebb eden 26 Figure 6 7 Configured Input txt file for the Chilgrove House evaluation
22. e available observational data including rainfall PET groundwater level and abstraction rates The Input txt file allows the user to specify a number of options such as which module components and simulation mode they wish to use The files stored in the Calibration and Evaluation folders are only used when AquiMod is set to run in these respective modes They contain ranges or specific parameter values to be used by AquiMod when running in calibration and evaluation mode respectively Finally the Output folder is where all model outputs are generated lele TONE Computer OS C CHexample Search CH P Organize v Aa Open Include in library v Share with Burn New folder v al NA Calibration Evaluation Output Input bd vr Favorites BE Desktop amp Downloads Recent Places de Google Drive Y Objective 23 Dropbox A Libraries Documents A Music Observations txt Pictures Subversion B Videos ma Computer amp os c DVD RW Drive D Ma ca DATA E Si Calibration _ A File folder Date modified 15 04 2014 11 36 Figure 5 1 Folder structure of AquiMod 5 2 INPUT FILES 5 2 1 Observations txt Before running AquiMod the user must specify four observation time series as shown in Table 5 1 These time series can be summarised as follows e Climate rainfall and PET A continuous time series of rainfall and PET data is required to dr
23. e 3 1 Table 3 1 Summary of soil zone module components ID Name Description 1 FAO Drainage from the base of the soil zone is calculated using a soil water balance method based on a simplification of the algorithm developed by the UN Food and Agricultural Organisation Allen et al 1998 3 1 1 FAO This component simulates soil moisture as a function of vegetation and soil properties The soil column is conceptualised as a bucket with a maximum volume of water available to plants after the soil has drained to its field capacity Figure 3 1a This is termed the total available water TAW which is calculated as TAW Z FC WP 1 where Z is the estimated maximum root depth L of the vegetation and FC and WP are the soil field capacity and wilting point respectively As the soil moisture content decreases it becomes more difficult for vegetation to extract moisture from the soil matrix The proportion of TAW that can easily be extracted before this point is reached is conceptualised as readily available water RAW which is calculated as RAW p TAW 2 where p is the depletion factor of the vegetation The water balance of the soil zone is a function of the rainfall input and evaporative flux from the soil and can be written as ASMD AET PPTN 3 where SMD is the soil moisture deficit L PPTN is the total precipitation input L and AET is the actual evapotranspiration L which is calculated as
24. e 5 1 the model has been configured to run on a monthly time step producing groundwater level simulations at the end of each month 5 2 1 2 INITIAL CONDITIONS AquiMod assumes a dry soil and unsaturated zone initially The saturated zone is always initialised at the first time step where an observed groundwater level measurement is available in Observations txt If this is not the first time step as well as initialising the model at the first groundwater level observation AquiMod also uses the mean of all available groundwater level data in Observations txt to initialise the model at the first time step In the example the first time step has a groundwater level measurement of 70 7 m and as such this is used to initialise the saturated zone component 5 2 1 3 IMPOSED GROUNDWATER LEVELS As well as initialising the model with the observed groundwater levels it is also possible to impose observed groundwater levels mid simulation By doing so the model discards the simulated level for that time step and uses the observed level instead This can be done at one or more time steps by placing an asterisk at the end of the corresponding row s in Observations txt Table 5 2 16 OR 14 007 Table 5 2 Imposing groundwater levels in the Observations txt file Line File text Description number 1 NUMBER OF OBSERVATIONS 2 540 3 DAY MONTH YEAR RAIN PET GWL ABS 4 31 1 1961 48 0 42 70 7 0 0 5 28 2 1961 3 1 0 54 67 6 0 0 Here the
25. features of the AquiMod software include Fast simulation of groundwater level time series Flexible time stepping Monte Carlo parameter sampling Modular structure with multiple process representations Choice of objective functions to evaluate model efficiency 11 INTENDED USE AquiMod can be applied to any groundwater catchment around an observation borehole with observed groundwater level time series data It can be calibrated against these data and used to provide information on the behaviour of groundwater levels beyond observational records The model has been used in this way for a number of applications including reconstructing groundwater level records long term projections of groundwater levels under climate change and forecasting groundwater levels into the near future using meteorological forecasts Of course this list of applications is not absolute and users are encouraged to experiment with the software However it is important to consider the limitations of the AquiMod when deciding if it is suitable for your intended use Please refer to a summary of these limitations in Table 1 1 Table 1 1 Considerations and potential limitations when applying AquiMod for groundwater level simulation Consideration Limitation Lumped model structure AquiMod lumps the catchment area into a single response unit which is characterised by a groundwater level borehole hydrograph It treats each input variable e g soil type and rainfal
26. g input text files for each module component These files must be located in the Evaluation folder and they follow a standard naming convention _eval txt where the asterisk should be replaced by the component name Table 5 5 provides an example of the FAO_eval txt file Here only a single parameter set is defined but multiple parameter sets can be included on separate lines e g see Section 6 2 Table 5 5 Example of FAO _eval txt file Line File text Description number 1 FieldCapacity WiltingPoint MaxRootDepth mm DepletionFactor BaseflowIndex Header Line 2 0 31 0 15 2000 0 0 6 0 85 Parameter values 19 OR 14 007 5 3 OUTPUT FILES After executing the AquiMod software a series of output files will be generated in the Output folder the number of files generated depends on the user specifications in Input txt All output files use the out file extension 5 3 1 Calibration output files Assuming that the output file switches in the input txt file have all been set to Y AquiMod will produce a single output file for each module component selected for a calibration run These files follow the naming convention _calib out where the asterisk is replaced by the component name An example Weibull_calib out file is shown in Table 5 6 Within these files the parameter sets that resulted in a simulation that met acceptable model threshold as defined in input txt are listed Note that the file
27. ge of values from which the Monte Carlo parameter sets are randomly sampled see Appendix 1 for a list of recommended ranges All files have the same naming convention _calib txt where the asterisk should be replaced by the component name An example of the FAO _calib txt calibration input file is given in Table 5 4 Note the general structure header lines followed by two numerical values which specify the maximum and the minimum of the range of values to be sampled randomly Also note that parameters can be fixed simply by specifying the same minimum and maximum values as has been done for the field capacity parameter Note that template files for all module components can be downloaded from the AquiMod website Table 5 4 Example of the FAO _calib txt calibration input file format The field capacity line 2 is fixed while the root depth line 8 will change for each calibration run Line File text Description number 1 Field Capacity Comment Line 2 0 31 0 31 Minimum and maximum value 3 Blank 4 Wilting Point Comment Line 5 0 10 2 Minimum and maximum value 6 Blank 7 Root Depth mm Comment Line 8 100 3000 Minimum and maximum value 9 Blank 10 Depletion Factor Comment Line 11 0 01 0 99 Minimum and maximum value 12 Blank 13 Baseflow index Comment Line 14 0 70 9 Minimum and maximum value 5 2 4 Evaluation input files In evaluation mode AquiMod requires the user to specify one or more parameter sets usin
28. ive the model specified in units of mm d 15 OR 14 007 e Groundwater levels At least one time stamped measurement of groundwater level is required specified in units of metres above a datum AquiMod uses these data to calculate the specified objective function Where measurements are not available a 9999 value should be entered e Abstraction rates A continuous abstraction rate time series specified in units of mid is required This is subtracted from the saturated zone component during simulation The number of observations must also be input on line 2 In the example shown in Table 5 1 a total of 540 time steps are specified which run from January 1961 Table 5 1 Example Observations txt file Line File text Description number 1 NUMBER OF OBSERVATIONS Comment Line 2 540 Number of time steps for simulation 3 DAY MONTH YEAR RAIN PET GWL ABS Headers for columns 4 31 1 1961 48 0 42 70 7 0 0 day month year rain mm d PET mm d groundwater level m groundwater abstraction rate m d 5 28 2 1961 3 1 0 54 67 6 0 0 6 31 3 1961 0 07 1 1 59 3 0 0 The Observations txt file can also be used to specify a number of other conditions including 5 2 1 1 MODEL TIME STEP The model time step is defined by the length of time between each time stamp in the Observations txt file The minimum time step is one day and the time step length can vary throughout the simulation sequence Note that in Tabl
29. l and output variable e g groundwater level as spatially uniform over your chosen study area and therefore cannot provide information on spatial heterogeneity within a given catchment area Time series data AquiMod needs observed groundwater level time series to evaluate the model against and corresponding rainfall and potential evapotranspiration PET data to drive the model Model boundary AquiMod assumes that the groundwater catchment receives recharge from rainfall only i e it does not account for other sources of recharge such as lateral groundwater flows across the catchment boundary OR 14 007 12 GENERALISED STRUCTURE AquiMod consists of three modules Figure 1 1 The first is a soil water balance module that partitions rainfall between evapotranspiration runoff and soil drainage This module simulates the water balance of the root zone therefore soil drainage is defined as the water that percolates past the root zone and is no longer available for evapotranspiration Drainage from the soil is then attenuated through an unsaturated zone module which represents percolation to the groundwater table as recharge This recharge is input to the saturated zone module that simulates aquifer storage and subsequent discharge It is the saturated zone module that calculates the groundwater level time series Evapotranspiration Rainfall Soil root zone Soil drainage Unsaturated zone Recharge Groundwater abstr
30. le the remainder are fixed This was determined based on the availability of catchment data Open the FAO_calib txt file located in the Calibration folder The field capacity wilting point and baseflow index parameters have been fixed based on known catchment information obtained from a soil database of the United Kingdom Boorman et al 1995 while the maximum root depth and depletion factor are to be randomly sampled between specified ranges Next open the Weibull_calib txt file The Weibull lambda and n parameters have been determined by analysing the relationship between rainfall and groundwater levels The lambda parameter controls the location of the peak of the Weibull distribution or in other words the peak recharge response to rainfall and subsequent soil drainage As such a cross correlation analysis has been performed between monthly rainfall and groundwater levels Figure 6 4 that shows a peak correlation at a 1 month lag Accordingly the lambda range has been set from 1 2 5 The n parameter has been set to 6 as this is the longest lag that shows a significant correlation also note that this was used to define the spin up period in Input txt The k parameter range has been set to 1 7 which is a typical range for this distribution parameter 24 OR 14 007 Correlation Lag months Figure 6 4 Cross correlations between rainfall and de seasonalised groundwater levels Finally open Q3K3S1 calib txt The aq
31. n Qs m d Q m d Q m d GWL m above datum Groundwater discharge from top aquifer layer Groundwater discharge from middle aquifer layer Groundwater discharge from bottom aquifer layer Groundwater level Q2K2S1 Variable units Description Q m d Q m d GWL m above datum Groundwater discharge from the top aquifer layer Groundwater discharge from bottom aquifer layer Groundwater level 32 OR 14 007 Q1K1S1 QITIS1 VKD Variable units Description A m d GWL m above datum Groundwater discharge Groundwater level Variable units Description Q m d GWL m above datum Groundwater discharge Groundwater level Variable units Description Q m d GWL m above datum Groundwater discharge Groundwater level 33 OR 14 007 References The British Geological Survey holds most of the references listed below and copies may be obtained via the library service subject to copyright legislation contact libuser bgs ac uk for details The library catalogue is available at http geolib bgs ac uk Allen R G Pereira L S Raes D amp Smith M 1998 Crop evapotranspiration Guidelines for computing crop water requirements FAO Irrigation and drainage paper 56 Food and Agriculture Organization of the United Nations Boorman D B Hollis J M amp Lilly A
32. nage for each time step is calculated using a two parameter Weibull probability density function k px k 1 A 0 x lt 0 where k gt 0 is the shape parameter and A gt 0 is the scale parameter of the distribution The A parameter primarily controls the location of the peak in the probability density function while k controls the density of the function around the peak Figure 3 2 The resulting distribution is scaled such that the discrete integral of f is equal to unity and consequently the recharge for each time step R is spread over the selected number of time steps n Ree 23 fx SDi x 1 7 where a is the scaling parameter The Weibull function can represent exponentially increasing exponentially decreasing and positively and negatively skewed distributions It is used because it allows the exploration of different distributions whilst being smooth which is considered to be more physically justifiable than randomly selected monthly weights tr 0 9 F 0 8 F gt O a a oe OON 00 00 HXXX A mo 20000 0 7 F En x ost ie ost 0 44 0 3 o 2t otf 0 0 2 4 6 8 10 Figure 3 2 Probability distribution function of the Weibull distribution using different 2 and k combinations 8 OR 14 007 3 3 SATURATED ZONE MODULE There are currently five different saturated zone components available in the AquiMod software as summarised in Table 3 3 Table 3 3 Summary of saturated zone module componen
33. onent IDs this should remain the same as you will use the same module components e Simulation mode set this to e to run AquiMod in evaluation mode Number of runs Set this to the number of acceptable parameter sets that were obtained from the previous tutorial Objective function this should remain the same Spin up period this should remain the same Acceptable model threshold this option is not used in evaluation mode Maximum number of acceptable models this option is not used in evaluation mode Write model output files in evaluation mode the output files will contain the time series simulations for the acceptable models In this tutorial you will only assess the groundwater level simulations so set the first two to N and the last one to Y Figure 6 7 shows the completed Input txt file for this exercise 27 OR 14 007 4 C CHexample Input txt Notepad File Edit Search View Encoding Language Settings Macro Run Plugins Window SH BDO 3 dsl IE en H input be Component IDs Yd Simulation mode e Number of runs 1000 Objective function 1 Spin up period 6 Acceptable model threshold calibration only 0 8 Maximum number of acceptable models calibration only 1000 Write model output files NN Y length 265 lines 23 Ln 23 Col 6 Sel 0 Dos Windows ANSI Figure 6 7 Configured Input txt file for the Chilgrove House evaluation run 6 2
34. ry usage and virtual memory Settings User Profiles Desktop settings related to your logon Startup and Recovery System startup system failure and debugging information Settings Figure 2 1 System properties window IMPORTANT The path address for the CHexample folder must contain no whitespace 3 OR 14 007 e Under the System Variables header find the Path variable and click Edit Figure 2 2 Environment Variables User variables for Jon Variable Value TEMP E Temp TMP E Temp PATHEXT COM EXE BAT CMD VBS VBE JS PROCESSOR A _AMD64 New I edt Delete Cx JL cme Figure 2 2 Environment Variables window e At the end of the Path Variable value line insert a semicolon followed by the address of the AquiMod folder In the example shown in Figure 2 3 this folder was copied directly to the C drive Edit System Variable Variable name Path Variable value ioft SQL Server 90 Tools bi Figure 2 3 Edit System Variable window AquiMod is now ready to use OR 14 007 2 2 RUNNING AQUIMOD The AquiMod executable is run using the Windows command prompt which can be accessed by typing cmd into the search bar of the Start menu and hitting the return key Once the command prompt has loaded AquiMod can be run by typing aquimod followed by the directory address of the model files separated by
35. s is available from BGS shops at Nottingham Edinburgh London and Cardiff Welsh publications only see contact details below or shop online at www geologyshop com The London Information Office also maintains a reference collection of BGS publications including maps for consultation We publish an annual catalogue of our maps and other publications this catalogue is available online or from any of the BGS shops The British Geological Survey carries out the geological survey of Great Britain and Northern Ireland the latter as an agency service for the government of Northern Ireland and of the surrounding continental shelf as well as basic research projects It also undertakes programmes of technical aid in geology in developing countries The British Geological Survey is a component body of the Natural Environment Research Council British Geological Survey offices BGS Central Enquiries Desk Tel 0115 936 3143 email enquiries bgs ac uk Fax 0115 936 3276 Environmental Science Centre Keyworth Nottingham NG12 5GG Tel 0115 936 3241 email sales bgs ac uk Fax 0115 936 3488 Murchison House West Mains Road Edinburgh EH9 3LA Tel 0131 667 1000 Fax 0131 668 2683 email scotsales bgs ac uk Natural History Museum Cromwell Road London SW7 5BD Tel 020 7589 4090 Fax 020 7584 8270 Tel 020 7942 5344 45 email bgslondon bgs ac uk Columbus House Greenmeadow Springs Tongwynlais Cardiff CF15 7NE Tel 029 2052 1962 F
36. se British BGS Geological Survey NATURAL ENVIRONMENT RESEARCH COUNCIL AquiMod User Manual v1 0 Environmental Modelling Programme Open Report OR 14 007 BRITISH GEOLOGICAL SURVEY Environmental Modelling Programme Open Report OR 14 007 AquiMod User Manual v1 0 J D Mackay CR Jackson L Wang The National Grid and other Ordnance Survey data Crown Copyright and database rights 2014 Ordnance Survey Licence No 100021290 Keywords Groundwater model Groundwater level Lumped conceptual modelling AquiMod Bibliographical reference MACKAY J D JACKSON CR WANG L 2014 AquiMod User Manual v1 0 British Geological Survey Open Report OR 14 007 42pp Copyright in materials derived from the British Geological Survey s work is owned by the Natural Environment Research Council NERC and or the authority that commissioned the work You may not copy or adapt this publication without first obtaining permission Contact the BGS Intellectual Property Rights Section British Geological Survey Keyworth e mail ipr bgs ac uk You may quote extracts of a reasonable length without prior permission provided a full acknowledgement is given of the source of the extract Maps and diagrams in this book use topography based on Ordnance Survey mapping NERC 2014 All rights reserved Keyworth Nottingham British Geological Survey 2014 BRITISH GEOLOGICAL SURVEY The full range of our publication
37. simulated groundwater level will be discarded and set to the observed level 6 31 3 1961 0 07 1 1 59 3 0 0 5 2 2 Input txt The Input txt file is where the user can specify a number of different options each indicated by a corresponding header line Table 5 3 These are detailed as follows e Component IDs The ID numbers for the desired soil unsaturated and saturated zone components as indicated in the Tables in section 3 For example in Table 5 3 all have been set to 1 which indicates that the FAO Weibull and Q3K3S1 components are to be used e Simulation mode Here the choice of either calibration c or evaluation e mode is specified e Number of runs The number of runs can range from 1 to approximately 10 the maximum in calibration mode is dependent on available computer memory e Objective function Here the objective function used to evaluate the model simulations against the observed levels in Observations txt is specified e Spin up period Due to the fact that the soil and unsaturated zone components are initiated without any water in them there is an initial wetting up period or spin up period where AquiMod may not be able to simulate the groundwater level time series adequately which can result in poor optimization of the model parameters when running in calibration mode To prevent this the length of this period should be specified as a number of time steps AquiMod will then ignore this
38. structure is identical to the evaluation input files This allows for easy transfer between calibration and evaluation modes see Section 6 2 Table 5 6 Example of FAO_calib out file Line File text Description number 1 k lambda n timesteps Header Line 2 2 78 2 43 6 Parameter values 3 4 43 2 10 6 4 6 49 1 64 6 5 3 12 2 06 6 In conjunction with the module component output files a fit_calib out file is also produced see example in Table 5 7 which lists the corresponding objective function scores of the acceptable parameter sets obtained Table 5 7 Example of fit_calib out file produced by AquiMod using the NSE objective function Line File text Description number 1 ObjectiveFunction Header Line 2 0 913 Objective function score 3 0 912 4 0 908 5 0 907 5 3 2 Evaluation output files Assuming that the output file switches in the input txt file have all been set to Y AquiMod will produce a time series output files for each parameter set specified in the _eval txt files and each module component selected for a given evaluation run These files follow the naming convention 20 OR 14 007 l TimeSeries out where is the component name and is the model run number An example of the Q3K3S1 output file for parameter set 1 is shown in Table 5 8 Note that here the output variables include the simulated discharges from the three outlets and the groundwater level time series For more
39. tained from the calibration run If the fit_calib out file is empty that means no acceptable models have been obtained In this case you may wish to reconsider the criteria for accepting a model increase the number of runs adjust the parameter calibration ranges or experiment with different model structures 26 OR 14 007 6 2 HOW TO PERFORM AN EVALUATION RUN This tutorial provides guidance on how to use AquiMod in evaluation mode Here AquiMod does not employ the Monte Carlo parameter sampling Instead you are required to specify the parameters As such in evaluation mode AquiMod does not output any information on model parameters but instead generates the simulated time series for the defined parameter sets In this sense it allows you to evaluate specific model structures and parameter sets by visually comparing the observed and simulated time series In this tutorial you will evaluate your newly derived parameter sets from the previous section against all of the available data between January 1961 and December 2005 6 2 1 Observations txt First you need to specify the observed sequence in the Observations txt file This data can be found in ObsEval txt Simply copy and paste this into Observations txt Note that as before we are still running the model on a monthly time step with no abstraction 6 2 2 Input txt Next you will configure Input txt Open Input txt in a text editor Going through each option in order e Comp
40. tal groundwater discharge is the sum of discharge from all layers in the saturated zone which is calculated using an equation of the form TAY 9 Q gt ET i where 1 is the layer number for m layers and Ah L is the difference between the groundwater head and the elevation of the aquifer outlet point Importantly due to the explicit form of Equation 9 used the groundwater head at the previous time step h L is used h Zi h gt Zi 10 Ahi 0 h lt Zi where z is the outlet elevation Transmissivity T L T is a function of the hydraulic conductivity L T ki and is calculated using the following piece wise function 9 OR 14 007 0 h lt Zi i 1 m T K h Zi Zi lt h lt Zi 1 i lt m 11 KZ zo AZ i lt m Ky h Zm h gt Zm i m Using this component the hydraulic conductivity can be configured to increase or decrease with depth according to the user s preference However for some aquifers it may be preferable to have an increasing hydraulic conductivity with elevation As such an additional a parameter also exists for this component which can be switched to force this condition when using randomly sampled Monte Carlo parameter sets See Appendix 1 Figure 3 3 Q3K3S1 saturated zone component 10 OR 14 007 3 3 2 Q2K2S1 This component employs the same structure according to equations 8 11 however here only two layers are defined Each layer is independent and h
41. ts ID Name Description 1 Q3K3S1 A three layer aquifer representation each of variable thickness and permeability 2 Q2K2S1 A two layer aquifer representation each of variable thickness and permeability 3 Q1K1S1 A single layer aquifer representation 4 Q1T1S1 A confined aquifer representation with a fixed transmissivity 5 VKD An aquifer with a cocktail glass representation of the change in hydraulic conductivity with depth 3 3 1 Q3K3S1 This component represents flow in the saturated zone by a rectangular block of aquifer with dimensions Ax and Ay denoting its length and width L respectively A mass balance calculation is performed at each time step to calculate the new groundwater head dh 8 RAxAy Q A SAxAy g where R is recharge input L Ti Q is the total groundwater discharge pi FJ A L q 1s any additional abstraction S is the storage coefficient dimensionless and dh is the change in groundwater head L over time dt T This component accommodates three layers of variable thickness and permeability Figure 3 3 Each layer is independent and has its own discharge outlet The deepest layer represents groundwater which flows out of the catchment via subsurface flow paths The two upper outlets are lumped representations of surface discharge points in the catchment including rivers and springs Both may flow intermittently if the groundwater head falls below the outlet elevation The to
42. tsseesstesseesseeesseeessresseesse 22 6 2 How to perform an evaluation TUN venne ennevennervennervennervenvereenvervenseevenveeven seren 27 6 3 Deactivating modules and using other components annae veen neeeeneeeeenverenn 29 VL D S E A A T id Soil zone component parameters A da 31 Unsaturated zone component parameters sssessssesseessessseesssetssrtssetssetesseetsstessersseesseesseees 31 Saturated zone component parameters terende dndiek 31 Appendix 2s icassisconseevetsassssesceausciaceenssndaeensncesdndssacabevodasasusssucsoeusdsasbavoeneadasbucdesassancsevsssuasiodesbuabaaties SD Soil zone component output variables enen onne vo onneneennervennervenseevenneerenseereneerenn 32 Unsaturated zone component output variables nanne onno evenneerenneevennervenneevenveeenn 32 Saturated zone component output variables naven ov onneevennervenvervenneerenveevenverenn 32 Redee viii iii O4 OR 14 007 FIGURES Figure 1 1 Generalised structure of AquiMod enne eeneeeenseenneenneernveeenveenn 2 Figure 2 1 System properties WII Wii desta 3 Figure 2 2 Environment Variables windoW 0d A aa 4 Figure 2 3 Edit System Variable Window tsaren ae a A da 4 Figure 2 4 Running AquiMod through the command prompt conoccnocccnnconononannnonanononcnononananonaconnncnnss 5 Figure 3 1 a FAO soil zone component conceptualised as a bucket with a finite capacity and b the change in ratio of AET to PET with SMD as described
43. uation mode a separate file is output for each model component and model run which may slow down the overall model run time Table 5 3 Example Input txt file Line File text Description number 1 Component IDs Comment Line 2 111 Module component selection Soil Unsat Sat integers 3 Blank 4 Simulation mode Comment Line 5 e Simulation mode c calibration e evaluation 6 Blank 7 Number of runs Comment Line 8 1 Number of model runs for calibration and evaluation modes 1 to 10 integer 9 Blank 10 Objective function Comment Line 11 1 Objective function ID integer 12 Blank 13 Spin up period Comment Line 14 6 Spin up period over which objective function will not be calculated number of time steps integer 15 Blank 16 Acceptable model threshold calibration only Comment Line 17 0 9 Objective function which must be reached for results to be output float 18 Blank 19 Maximum number of acceptable models calibration only Comment Line 20 1 Maximum number of acceptable models output from calibration mode integer 21 Blank 22 Write model output files Comment Line 23 YYY Switch for writing output files Soil Unsat Sat Y yes write output file N no do not write output file 18 OR 14 007 5 2 3 Calibration input files When running in calibration mode a separate input file for each module component must be configured in the Calibration folder These files specify the ran
44. uifer length has been fixed to 3000 m which is the approximate length between the borehole and the nearest river in the catchment where the groundwater discharges The bottom elevation of the aquifer has been set based on the known geometry of the Chalk aquifer in this catchment The second layer outlet elevation has also been set The top layer elevation has been kept as a calibration parameter and is free to fluctuate between ground level elevation and the minimum groundwater level on record i e within the zone of fluctuation The specific yield and hydraulic conductivity ranges have been set based on known Chalk properties In this case the conductivities have been set to decrease with depth as this is a common characteristic of the Chalk aquifer Due to the fact that some of the conductivity ranges between layers overlap the alpha parameter has been set to 1 to ensure that the conductivity decreases with depth 6 1 5 Running AquiMod in calibration mode Having configured all of the required input files AquiMod is now ready to run as shown in section 2 2 Run AquiMod in the command prompt Notice a slight difference in the output messages for this run in comparison to the initial evaluation run conducted in section 2 2 Figure 6 5 The first message states that the model is running 100 000 times The second states that it is extracting the best models Generally this is instantaneous but when storing large numbers of parameter sets it can become
Download Pdf Manuals
Related Search