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User's manual for the distributed recharge model ZOODRM

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1. Rainfall Raingrid dat number of raingauges theissen polygons distribution of long term average rainfall Hit 200 daily rainfall for each raingauge Potential Evaporation Evapgrid dat number of evaporation stations theissen polygons distribution of long term average PE pe or txt monthly PE data Soil moisture deficit calculation Plants asc distribution of plant types recharge node id 1 Plants dat Number of crop types per node CDValues dat monthly C and D values for each plant Wetting threshold method recharge Soil asc distribution of soil types node id 2 Soil dat monthly values of ST FAO recharge calculation recharge Plants asc distribution of plant types node id 5 Plants dat Number of crop types per node CropFAO dat Specific data for FAO method Soil asc distribution of soil types Soil dat Specific data for FAO method Urbanised areas recharge node id Urbanareas asc Distribution of urban areas 3 Urbanarea dat Data for each urban area Irrigated areas recharge node id _Irrigatedareas asc Distribution of irrigated areas 4 Irrigatedarea dat Data for each irrigatedarea Rivers Rivers dat ZOOM ZETUP file with structure of rivers Aspect asc aspect map for producing routing to rivers River dat data for each river Geology asc distribution of geological outcrops for runoff run on and river losses ROValue dat runoff and
2. The list of input files required by ZOODRM is presented in Table 1 and are grouped into categories Though there are 29 files listed not all of these are required for all simulations The files are listed by mechanism in Table 2 and are cross referenced in this table to the relevant section in this report Each of the ZOODRM input files is described in the following section The nodes in ZOODRM are created from the information contained in the file grids dat This file is created by ZETUP the pre processor to ZOOMQ3D This ensures that the recharge model calculates recharge in exactly the same place as nodes in the groundwater model The file recharge asc which is produced by ArcView contains an areal distribution of recharge calculation node types Currently there are five node types in the model 1 Soil moisture deficit approach 2 Wetting threshold method for semi arid regions 3 Urban recharge method 4 Irrigated areas 5 EA FAO method The mechanisms required at each recharge node are chosen by specifying an integer id number in the appropriate position in the array contained in the file recharge asc The array in recharge asc is independent of the grid structure defined in the file grid dat This independence enables areas of recharge mechanisms to be specified regardless of any grid refinement The general philosophy of the input files for ZOODRM is an array generated by ArcView containing integer id numbers These id numbers pr
3. Acknowledgements As with all projects there a number of people to thank for their help and assistance Acknowledgment is given to Chris Jackson for his help especially in providing advice for the development of object oriented models Denis Peach and Nick Robins are also gratefully acknowledged for helping both with the code development and application on projects Finally John Bloomfield is acknowledged for his help in reviewing this document Preface to the second edition This second edition of the ZOODRM manual complements the release of version 1 01 of the recharge model code To run version 1 01 of the recharge model using the files prepared for version 1 0 some of the input files need to be modified These are the main input file Section 5 9 2 Table 22 the main rainfall file and associated files related to the raingauge stations Section 5 2 Table 6 and Table 7 and the main evaporation file Section 5 3 Table 8 The main alterations to the previous version of the model are e Adjustment of the input files so that all grids are referred to by the co ordinates of their lower left corner e Addition of the possibility of selecting between runoff coefficient values that either vary on a monthly basis or are related to the rainfall intensity and the soil moisture deficit e Modification of some of the output files for ZOOMQ3D compatibility e Minor bug fixes Preface to the third edition This third edition of the ZOODRM manu
4. Maximum 3 Calculation of the potential recharge R If EP lt 0 R 0 0 If EP gt 0 R O EW RO C and R EW 1 R OC Where P Precipitation L T PE Potential evaporation L T WD Wetting Depth L EW Excess Water L SD Soil Threshold L R Recharge L T R O Runoff L T R O C Runoff coefficient 2 2 3 Environment Agency FAO method A review of recharge estimation for British aquifers carried out by Rushton 2000 includes the development of a new soil moisture balance recharge estimating approach This method relates the soil moisture deficit value to the water content of the soil and the crop water requirements to calculate the evapotranspiration and the recharge The evaporation from bare soil is also considered This method is described briefly in this section A full description can be found in the Groundwater Resources Modelling Guidance Notes and Template Project Brief Version 1 document prepared by the Environment Agency EA EA 2002 This method uses a better approach to calculate the evapotranspiration of plants In addition similar to the conventional SMD method the recharge calculation is also based on the SMD level however the temporal changes of the crop and soil characteristics are taken into consideration The calculations start by firstly defining a potential evaporation of a reference crop ETo The potential evaporation of any crop is then given by ET K ETo where Kc is the crop coefficient
5. The full range of Survey publications is available from the BGS Sales Desks at Nottingham Edinburgh and London 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 The Survey publishes an annual catalogue of its maps and other publications this catalogue is available from any of the BGS Sales Desks 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 its basic research projects It also undertakes programmes of British technical aid in geology in developing countries as arranged by the Department for International Development and other agencies The British Geological Survey is a component body of the Natural Environment Research Council British Geological Survey offices Keyworth Nottingham NG12 5GG T 0115 936 3241 Fax 0115 936 3488 e mail sales bgs ac uk www bgs ac uk Shop online at www geologyshop com Murchison House West Mains Road Edinburgh EH9 3LA 0131 667 1000 Fax 0131 668 2683 e mail scotsales bgs ac uk London Information Office at the Natural History Museum Earth Galleries Exhibition Road South Kensington London SW7 2DE 020 7589 4090 020 7942 5344 45 Fax 020 7584 8270 email bgslondon
6. 1 Output files that give the calculated recharge values 2 Output files that give the time series results at given locations in the study area at the rivers and at the springs 3 DXF and AutoCAD script files for plotting the constructed grids rivers and other features and checking the connections between these features Input files with extension asc and some other input files are reproduced by the model The new files hold the same names of the original files but have extensions of mr Table 26 shows a list of the output files produced by ZOODRM These files are separated in this table based on their type or based on the feature they represent 46 Table 26 Model feature Unsaturated nodes Recharge nodes Rivers Springs Ponds Output files produced by ZOODRM Output file type Recharge results Script files Water balance AutoCAD script files DXF files Model results Script files Model results Model results Script files 6 2 RECHARGE RESULTS The calculated recharge values are written to three of output files These are 1 Main output file rech out Monthly recharge file rech tv 2 3 Daily recharge file dailyrech tv 4 Monthly time series at the required locations as specified in rechydro dat rechts Relevant file names Rech out Rech ts Rech tv dailyrech tv UnsatToRech scr UnsatToSpring scr DailyWBGrid out LinkBR scr LinkTL scr RoutingGrid scr
7. Plants asc file defines the plant type at each model node when the calculation method flag is set to zero The values presented in the blocks of data give the percentage each crop occupies at the considered location The number of blocks is equal to the sum of the numbers of the two crop types and if there are n SMD crops the n 1 block of data corresponds to the first FAO crop This file is detailed in Table 11 It should be noted that at a location where the SMD recharge calculation is applied the sum of numbers given by the SMD blocks should be equal to 100 at this location The numbers in the FAO blocks should be zeros at the considered locations 32 Table 11 Details for file Plants dat PercentageLanduse 1 000000000 0000000000 0000010101515 15 15 etc PercentageLanduse 2 000000000 00000 45 20 30 60 0000010101515 15 15 etc PercentageLanduse 3 000000000 00000 45 20 30 60 0000010101515 15 15 etc Calculation method flag If 0 the majority crop type is applied i e only one crop type is allocated to each recharge node If 1 the percentage crop type is applied each recharge node may be allocated more than one crop type Total number of crops in the area where the SMD recharge calculation method is applied Total number of crops in the area where the FAO recharge calculation method is applied A block of data always preceded by one comment line The data array should have the same size as the
8. RechGridBR dxf RechGridTL dxf Routing dxf FlowRiver out GaugingRiver out DSLink scr USLink scr SpringToRiver scr FlowAtSpring out pond out PondGrid scr The main output file rech out contains the following information Echoing grid setup Monthly recharge for each grid for both unlagged recharge and lagged if possible recharge 47 Summaries of monthly recharge for each class of geological characteristics as specified in geology asc LTA recharge for each grid as arrays and xyz format The model produces monthly recharge values or values at the end of the stress period and writes them to rech tv Finally monthly time series at the required locations as specified in rechydro dat rech ts 6 2 1 River flow gauging The river nodes of each river over which the river flow is monitored are specified in the input file of the river River dat The daily recorded flows at these nodes are written to one file corresponding to the considered river This file is called GaugingRiver out where represents the river number for example 01 The output file contains one line of data for each day with the following format Day Month Year Q OS gege A Qn where Day Month Year represent the date at the end of the day when flow is recorded Q is the flow M1 day cumulated at the first river node in one day Q2 is the flow MI day cumulated at the second river node in one da
9. bgs ac uk Forde House Park Five Business Centre Harrier Way Sowton Exeter Devon EX2 7HU T 01392 445271 Fax 01392 445371 Geological Survey of Northern Ireland 20 College Gardens Belfast BT9 6BS 028 9066 6595 Fax 028 9066 2835 Maclean Building Crowmarsh Gifford Wallingford Oxfordshire OX10 8BB 01491 838800 Fax 01491 692345 Sophia House 28 Cathedral Road Cardiff CF11 9LJ T 029 2066 0147 Fax 029 2066 0159 Parent Body Natural Environment Research Council Polaris House North Star Avenue Swindon Wiltshire SN2 1EU SS 01793 411500 Fax 01793 411501 www nerc ac uk Foreword This development of the ZETUP ZOOMQ3D and ZOOPT modelling software has been undertaken through a continuing tripartite collaboration between the University of Birmingham the Environment Agency and the British Geological Survey The recharge model ZOODRM has been developed by the British Geological Survey The development of ZETUP and ZOOMQ3D was initially undertaken at the University of Birmingham between 1998 and 2001 but continued after this time as a collaborative project between the three partner organisations Since the inception of the collaborative project the development of the software has been directed by the ZOOM steering committee the members of which are University of Birmingham Dr Andrew Spink Environment Agency Steve Fletcher Paul Hulme British Geological Survey Dr Denis Peach Dr Andrew Hughes Dr Chris Jackson
10. AE R 2 Calculate the SMD SMD 1 SMD AE R 3 Calculate the potential recharge If SMD lt 0 Recharge SMD Where R Rainfall L T PE Potential evaporation L T AE Actual evaporation L T C Root constant L D Wilting point L SMD Soil moisture deficit L 2 2 2 Wetting Threshold Method The application of the conventional SMD method to estimate recharge for areas in arid and semi arid regions is not possible because the soil moisture is often not at its field capacity This prohibits the instant occurrence of runoff and causes additional water losses to occur Besides in uncultivated areas of semi arid regions vegetation may develop at the end of the wet season and die within a short period and after a long dry period the effect of evapo transpiration from the dried vegetation is minimal Lange et al 2003 investigated the potential recharge in semi arid areas by undertaking sprinkler tests in a study area within the West Bank Palestine This study showed that no runoff is generated from rainfall over dry soil until a certain amount of rainfall is exceeded This contradicts with the assumption of the instant occurrence of runoff as implemented in the conventional method of recharge calculation In addition once the runoff appears on the surface its rate as a percentage of the rainfall intensity increases gradually and reaches a constant value which in the experiment is equal to 85 of the rainfall intensity A rech
11. Comment line The co ordinates X then Y of the nodes where SMD time series are produced Comment line output day month year 13 4 1972 Day Month Year End time for daily gridded output Day month year 13 4 1982 recharge Comment line Day Month Year 5 9 4 Recharge time series at a point Rechhydro dat input file is required to specify the locations where the recharge time series are recorded by the recharge model and written to the corresponding files Table 24 gives the structure of this file Table 24 Details for file Rechhydro dat Total number of nodes where the recharge time series are recorded by the model The co ordinates X then Y of the nodes where the recharge time series are recorded 296000 581600 294990 578850 296670 574320 5 9 5 Aspect file Aspect dat The aspect directions at selected can be changed using an input file named aspect dat The first line of this line specifies the number of nodes at which aspect directions are specified The locations of the nodes the X Y co ordinates and the aspect directions an integer from 1 to 4 where 1 indicates North 2 indicates East 3 indicates South and 4 indicates West are then listed Table 25 gives the structure of this file 44 Table 25 Details for file Aspect dat 460375 179350 1 460375 179375 2 460375 179400 3 460250 179600 4 Total number of nodes where the aspect directions are user specified A list of the
12. SPATIAL INFORMATION FILES The first set of input files are data files prepared in ArcView or ArcGIS ESRI and exported in ASCII Raster format These files represent the spatial characteristics of the study area They include its topographical geological and landuse characteristics The area information is gridded to the required resolution and then exported in the required asc ASCII format file The areal extent of these files should be larger than the extent of the recharge model area Figure 8 The parts that are outside the boundary of the recharge model are ignored and the model will produce an error message if a model node is outside the data file coverage If no grid refinement is considered it is preferable that these files are gridded in the ArcGIS environment using a cell size equal to the one used in the recharge model Using a cell size in the gridded data files that is larger or finer than the model cell size introduces errors and reduces the accuracy of the produced results This is caused by the information being extracted from the input files based on the values of the co ordinates of a single point instead of the size of the area of this cell When refinement is included the error introduced by gridding the spatial data cannot be avoided it is advised that data are gridded based on a cell size equal to the size of the cell located on the finer mesh A list of the required data files is given in Table 4 All these files have to e
13. and sewers that is calculated as a percentage of the daily water supplied to the area The second is the recharge from the grassed part and based on the application of the conventional SMD method In the latter case recharge is resulting from rainfall only and all factors such as evaporation effect of soil zone etc are taken into consideration The SMD calculated recharge is factored by the percentage of the area of the green part to the total urban area and added to the recharge resulting from water mains and sewer leakages The total calculated recharge is then passed to the unsaturated zone Unlike the other recharge nodes all urban area nodes are assumed to discharge the calculated runoff to one stream node This is to represent the fact that in urban areas runoff water is directed through storm water pipes that discharge at one specific location Rainfall is split by the relative proportions of Rainfall impermeable and grassed areas X 100 X Impermeable Grassed areas areas Runoff Runoff from Runoff is aggregated River Je Runoff SMD or WT grassed areas is for the urban arca and method routed to a single applied to a single wadi n de wadi node Leakage i Recharge Figure 6 Recharge calculation for urbanised areas 2 2 5 Irrigated Areas Irrigated nodes are SMD type recharge nodes but that receive in addition to
14. balance is the water balance calculated at the considered date and using the run on value calculated at the previous day 6 2 5 Pond output file pond out The model produces a file pond out that lists the locations of the ponds and their corresponding aspect directions aspect directions The in the file name replace the grid number where the listed ponds are located This file can be used to plot the ponds on a map It can be also used to correct the aspect direction at a node where representing a pond so that this pond can be eliminated from the model 50 References GRINDLEY J 1967 The estimation of soil moisture deficits Meterol Mag 96 1137 pp 97 108 HUGHES AG JACKSON CR RUTTER HK BLOOMFIELD JP RICHES J 2003 Development of a distributed recharge model using object oriented techniques MODFLOW and more 2003 Understanding through modelling Conference proceedings International Ground Water Modeling Center IGWMC Colorado USA JACKSON CR 2001 The development and validation of the object oriented quasi three dimensional regional groundwater flow model ZOOMQ3D British Geological Survey Internal Report IR 01 144 JACKSON CR and SPINK AFF 2004 User s manual for the groundwater flow model ZOOMQ3D British Geological Survey Internal Report IR 04 140 LANGE J GREENBAUM N HUSARY S GHANEM M LEIBUNDGUT C and SCHICK A P 2003 Runoff generation from successive simulated rainfalls on a rock
15. by line as explained by the rainfall file shown in Table 7 Note that the list of data must terminate by 1 1 1 Table 7 Explanation of the rainfall files giving the rainfall values at one rainfall station Glencaple Comment line giving the name of the rainfall station 1970 1970 1970 1970 1970 1970 1970 1970 1970 1970 1970 1970 1970 1970 Rainfall values at the considered times Year Month Day Value Time should be within the time interval specified in Raingrid dat input file o N OO A Go N l 5 i i i i The following approach is used by the model to distribute the rainfall data and applies for the inclusion of the evaporation data Rainfall is measured as a sequence of daily totals monthly in case of evaporation which depending on the location of the raingauge has a unique pattern of daily measurements and different long term averages The time series and totals of the rainfall are influenced by a number of factors including topography direction of prevailing wind etc To provide a distribution of rainfall an area associated with each raingauge is first defined This area can be used with the gridded LTA rainfall to enable the rainfall measured at a raingauge to be interpolated to any point within the area of influence of that raingauge Rainfall is then calculated by multiplying the rainfall at the raingauge by the ratio of the LTA at the point in space to the LTA of the raingauge Rf Rf L
16. code development is crucial for the incorporation of new approaches or for code enhancement The overall aim of the recharge model is to be flexible enough to cope with recharge processes that vary spatially over a study area and be able to change during a project as understanding increases The flexibility and power of object oriented programming are generated from the possibility of updating the code as the understanding of recharge processes develops Objects created in an object oriented code are representations of real world items Recharge for example is calculated at node objects representing area of the system Nodes can then be assigned different types of recharge calculation method These items are easily identified in an object oriented code and form the basis building blocks of the model Spink et al 2003 Another example is the data objects created in the model can be removed and replaced by other more sophisticated objects Gridded data objects for example can be replaced by software data objects such as ArcGIS objects or a statistical rainfall object could be used instead of the current data based rainfall object 13 THE RECHARGE MODEL The recharge calculation in the model is undertaken on a distributed basis that exploits OO techniques There are four different types of node objects These are recharge unsaturated river and spring node objects Node objects such as the recharge and unsaturated node objects are held on grid
17. discharges Spring dat input file gives the information required by each Spring object to connect to the recharge nodes This file is required in conjunction with the SpringData dat input file The input data of this file are explained in Table 20 Table 20 Details for file Spring dat Related Hydraulic conductivity m d Comment line 5 The hydraulic conductivity used to calculate the daily flow at this Spring object Linked geology types Comment line 41 The recharge nodes that are associated with geology type stated here will be connected to this Spring object The number of geology types is given in the input data file SpringData dat 5 9 OTHER INPUT FILES 5 9 1 Start and end time of model File Clock dat gives the start and the end time for the model simulation in day month and year as explained in Table 21 Table 21 Details for file Clock dat 1 1 1970 Simulation start time Day Month Year 1 1 1972 Simulation stop time Day Month Year 5 9 2 Input control file File Input dat is used to set two flags one to specify the use of the SMD or FAO calculation methods and the second to indicate that the recharge grid is different from the unsaturated grid In addition this file control the time at which the recharge results are produced There are two options The first is to produce the results at the end of a stress period equivalent to a corresponding month The second i
18. if required Section 5 9 2 A new format of rech tv output file when stress period approach is used The new format of rech tv matches the format of this file when blocks of years are used The format of rech db output file is corrected Note this file is not produced if the time stepping is different from days months and years Runoff routing output is modified River flows are produced in MI day rather than mm day A new output file dailyrech tv is added to produce gridded daily recharge values The time during which the gridded recharge values are produced must be set in the control file output dat Section 5 9 3 iii Contents OE WOE BE i PECKING WEE TINCT E ii PART Lefackeeumgkgutebeen eene 1 1L Introd ction E 1 ES We WER 1 1 2 Why object oriented approach eege 1 1 3 he recharee model E 2 Le SRST OGY eegene eege eege N 2 UE lg Tia GOTT VS TAN OT WEE 2 2 Modelling approach and key concepts essseoesssooesssooecesosecesssocecssoosessocesssooccesoscossssoossssoosse 3 SL Object Framework srenti o R E A E TEE a in aiii 3 DQ EE 5 PART2 Model EC EE 15 3 Running the E E 15 4 Summary of input files required by ZOODRM ssssesssssooesesssesoossesssesoossosssesoossosssessossosssese 16 4 1 The philosophy of model inputissic sssccecascssevevecssaversevevsnsversestelasgeesseseauseahedacesasccdevtyeceays 16 4 2 Relationship between groundwater and surface water catchments within the
19. one location may reach the spring at a time later than the end of the simulation The produced file gives the spring flows recorded from the start of the simulation to the times when the considered spring stops receiving water Care should be taken here since the spring flows recorded after the simulation stop time could be erroneous since no recharge is taken into consideration at these times 6 2 4 Water balance The different calculation water components are written to an output file named DailyWBGrid out on a daily basis This file aims for checking the water balance and has the following format Date Rainfall Evaporation Runoff Run_on Recovered water Recharge Water balance where Date is the date when the water components are recorded Rainfall is the total rainfall value calculated at all recharge nodes of all recharge grids mm Evaporation is the total evaporation value calculated at all recharge nodes of all recharge grids mm Runoff is the total runoff value calculated at all recharge nodes of all recharge grids mm Run_on is the total run on value calculated at all recharge nodes of all recharge grids mm This value is used to calculate the water balance of the following day Recovered water is the total water recovered from the soil calculated at all recharge nodes of all recharge grids mm Recharge is the total recharge value calculated at all recharge nodes of all recharge grids mm 49 Water
20. plants file Plants asc This file defines the crop type at each element of the data array The values of the data array are used if the majority landuse type is specified in plants dat the first value is set to zero in plants dat This grid file must exist if the SMD or FAO recharge calculation methods are used Sections 2 2 1 and 2 2 3 The user needs to specify explicitly in input dat Section 5 9 2 which of these recharge calculation methods is used If percentage landuse type is used the first value of plants dat is set to one Section 5 4 the data array is not used however it must exist set values to zero 5 1 5 The recharge file Recharge asc The values of the data array are integers specifying the application of the Soil Moisture Deficit SMD calculation method value of 1 the Wetting Threshold calculation method value of 2 or the FAO calculation method value of 5 Integers 3 and 4 relate to irrigated 25 and urban areas respectively but should not be entered in this array Refer to Sections 2 2 1 2 2 2 2 2 3 2 2 4 and 2 2 5 for the descriptions f the different method 5 1 6 The soil file Soil asc The values of the data array of this file are integers representing the IDs of the soil types This file relates to the application of the Wetting Threshold WT and FAO recharge calculation method For each soil type there must be a complementing data file Soil asc giving the wetting t
21. rivers dat grids dat UnsatMap asc Recharge asc rivers dat grids dat BaseUnsatGrid dat UnsatMap asc Recharge asc rivers dat grids dat UnsatMap asc Recharge asc rivers dat grids dat UnsatMap asc Recharge asc rivers dat grids dat BaseUnsatGrid dat UnsatMap asc Recharge asc rivers dat grids dat BaseUnsatGrid dat UnsatMap asc Recharge asc 22 grids dat and rivers dat Prepared by ZETUP Represent the surface catchment Prepared by ZETUP Represent the surface catchment Prepared by ZETUP Represent the surface catchment Prepared by ZETUP Represent the surface catchment Prepared by ZETUP Represent the surface catchment Prepared by ZETUP Represent the surface catchment BaseUnsatGrid dat Prepared by ZETUP Represent the groundwater catchment Prepared by ZETUP Represent the groundwater catchment Prepared by ZETUP Represent the groundwater catchment Recharge asc Covers the whole recharge grid Covers the whole recharge grid Covers the whole recharge grid Covers parts of the recharge grid Covers the whole recharge grid Covers the whole recharge grid UnsatMap asc Covers the whole unsaturated grid Covers the whole unsaturated grid Covers parts of the unsaturated grid Identical to Recharge asc Covers the whole unsaturated grid Covers the whole unsaturated grid 5 Detailed description of input files 5 1
22. run on values for each geology type Springs Topography asc land surface from DTM Springdata dat number and position of springs Spring dat data for each spring Time discretisation Clock dat start and end time or model simulation Input dat stress period setup Controlling data output Output dat daily output on or off Rechhydro dat time series of recharge at any given point 20 4 2 RELATIONSHIP BETWEEN GROUNDWATER AND SURFACE WATER CATCHMENTS WITHIN THE MODEL The recharge model ZOODRM is compatible with the groundwater flow model ZOOMQ3D Jackson 2001 in terms of the possibility of refining the numerical grids over selected areas and producing numerical recharge values at the nodes of the refined grids ZOODRM reads two files produced by ZETUP program a part of ZOOMQ3D to build numerical grids that are identical to ZOOMQ3D grids These files are grids dat and rivers dat The file grids dat contains the geometry and structure of the ZOOMQ3D model grids Whereas the file rivers dat contains the river geometry used for the ZOOMQ3D model A description of he structure of these files and how they can be created is given in the ZETUP user s manual Jackson and Spink 2004 It is likely that the areal extent of the surface water catchment could be different from the areal extent of the groundwater catchment The recharge model has to model the surface water catchment in this case and yet produce results over
23. soil moisture content at field capacity Permanent wilting point Comment line 0 24 Value of the soil moisture content at wilting point Depletion factor Comment line 0 39 Depletion factor 34 5 6 RECHARGE CALCULATION METHOD 5 6 1 Soil moisture deficit method The CDValues dat input file is required if a crop type to which the conventional SMD recharge method applies is considered in the model This file gives the monthly values of the root constant C and the wilting point D of the crop and the relationship between the actual evaporation and the potential evaporation when the soil moisture deficit value is located between C and D This file is detailed in Table 13 The number of the file is related to the id in the data array found in plants asc see Section 5 4 Table 13 Details for file CD Values dat Relationship between AE and PE when SMD is between C and D Root constant C and Wilting Point D for each month 5 6 2 Wetting threshold method This information is held within the soils object see Section 5 5 5 6 3 Environment Agency FAO method The CropFAO dat input file is required if a crop type to which the FAO recharge calculation method applies is considered in the model This file gives the characteristics of the crop as explained in Table 14 The number of the file is related to the id in the data array found in plants asc see Section 5 4 35 Table 14 Details for file C
24. the data file Plants dat that holds the information about the percentage area of the grid node area a crop covers The relationship between the objects i e the framework is illustrated by Figure 1 The main object is ZOODRM which holds all the other objects This object initiates all calculation and data objects For example it initiates the grid objects both the recharge and unsaturated grid objects which in turn create the calculation nodes it initiates the river and spring objects if they exist etc The objects that are derived from a base class are mentioned in a box within the base class The control of the time step and storage of the date is handled by the clock object CClock Input Data con Vv Model COOBRM cAspect CEvap AA _CTopomap CGrid CRain CRunoff CSoil CPlants CH m Clrrig Area i CRecharge SMD WT FAO Urban Irrig if CUrban Area CCrop s SMD FAO CRiver CGeology T CUnsatGrid wn CUnsat gt CSpring D Figure 1 Framework of the recharge model 2 1 1 Description of objects used within the model There are three different types of objects handled by the model These are the calculation objects which are responsible for quantifying the components of the recharge mechanisms the data objects which hold the spatial and te
25. to determining the rain information from the ASCII files For a given date the model searches for either 4 mon asc or 4 mon asc and reads the one that exists If both files exist mon asc is considered mon asc and mon asc input files have the format of the file shown in Table 5 Table 6 Details for file Raingrid dat 1000 1000 Mesh spacing in the X direction Ax Mesh spacing in the Y direction Ay Number of columns of the data array Number of rows of the data array 287000 588000 X followed by the Y co ordinates of the lower left comer 6 Number of rainfall station data to be read 1 1 1139 1 1961 12 2001 For each line Rainfall station id Substitute station Blackwood prn id LTA rainfall Start month Start year End 2 1 1042 1 1961 11 1998 month End year Name of file to be read CrichtonRoyal prn 3 1 1191 1 1961 2 2001 LochruttonWWks prn Grid of distribution of Theissen polygon Default substitute raingauge station LTAFactor LTAFactor 1 0 Multiplier for LTA values This factor multiplies the LTA values given in the block of data given next to produce the actual value of LTA rainfall 1257 1231 1201 1146 1145 1153 Grid of distribution of LTA values 1195 1185 1275 1257 1221 1207 1178 1128 1112 1107 27 The rainfall files may take any name with any extension however the recharge model is set to read one format of these files This is by reading the daily rainfall record line
26. to hold an id value of 1 2 or 5 at the location of a node to allow the creation of a recharge node at this location otherwise the existence of any other value will prevent a node being created Another ASCII file UnsatMap asc is introduced in the model to control the creation of the unsaturated node Before creating any new unsaturated node the recharge model uses this file to check if an id number of 1 is specified at this location If yes the node will be created otherwise the node creation is skipped Table 3 gives additional explanations about the different scenarios that can be dealt by the recharge model and the corresponding input files required 21 Table 3 Description of files Scenario Description 1 Surface and groundwater catchments are the same Surface and groundwater catchments are different Surface and groundwater catchments are the same Part of the unsaturated grid is not required Surface and groundwater catchments are the same Part of the recharge grid is not required Surface and groundwater catchments are different Part of the unsaturated grid is not required Surface and groundwater catchments are different Part of the recharge grid is not required Comment Flag set to N in input dat Flag set to Y in input dat Flag set to N in input dat Flag set to N in input dat Flag set to Y in input dat Flag set to Y in input dat Used Files
27. which the soil moisture is below the field capacity of the soil This technique calculates the change in Soil Moisture based on a relationship between Actual Evaporation AE and Potential Evaporation PE The relationship between AE and PE is derived from the Soil Moisture Deficit in relation to the Root Constant C and Wilting Point D as described in Figure 3 Water is assumed to be freely available from the part of the soil located between the ground surface down to a horizon equivalent to the value of C but only part of the water can be extracted from the soil when the SMD reaches or becomes greater than the value of C No water is extracted from the soil if SMD reaches or becomes greater than the value of D In the latter case the value of SMD is considered to be equal to the value D AE PE Actual evaporation Line slope AE a PE Line slope a a 0 1 Potential evaporation Figure 3 Relationship between Actual Evaporation and Potential Evaporation When the SMD reaches a value of zero the excess quantity of rainfall is considered as potential recharge The mathematical representation of this recharge calculation method can be summarized as follows 1 Calculation of Actual Evaporation If SMD lt CorR gt PE AE PE However if C lt SMD lt D and R lt PE AE R EF x PE R Where EF is an empirical factor and tends for Evaporation Factor It is represented by the symbol a in Figure 3 For all other cases
28. To determine if the considered crop can transpire at the potential rate the SMD level is compared to two parameters that are dependent on soil and crop characteristics The first parameter is the Total Available Water TAW which is given by TAW 1000 0 5c Oyp JZ where d Moisture contents at field capacity Hu Permanent wilting point Zr Root depth The second parameter is the Readily Available Water RAW where RAW is approximately 40 to 60 of TAW If the SMD level is less than RAW the plants transpire at the potential evapotranspiration rate If SMD is greater than RAW the plants transpire at a reduced rate equal to ET K Et where Ks is called the soil stress coefficient and varies from 0 to 1 based on the SMD value as illustrated in Figure 4 The plants do not transpire if the SMD value is greater than TAW A relationship between Ks RAW TAW and SMD can be TAW SMD established from Figure 4 This is given by K _ TAW RAW If the soil is bare the potential soil evaporation ES is given by ES Ks ET where Ke is the evaporation coefficient which is usually set to 1 1 The actual soil evaporation is given by K ES where K is an alternative soil stress coefficient which is determined as K but from two parameters the Total Evaporable Water TEW and the Readily Evaporable Water REW The first parameter is given by the following equation TEW 1000 8 c 0 50yp Z where Zes is the depth of
29. al complements the release of version 1 02 of the recharge model code To run version 1 02 of the recharge model using the files prepared for version 1 01 the raingrid dat input file needs to be modified Section 5 2 Table 6 A single alteration is made to this file This is e The default substitute raingauge station is defined at the line following the lines describing the details of rain gauge stations Preface to the third edition N This third edition N of the ZOODRM manual complements the release of version 1 03 of the recharge model code Version 1 03 of the model incorporates adjustments to the code to add flexibility for setting values of some of the input parameters and to improve the format of some of the output files To run version 1 03 of the recharge model using the files prepared for version 1 02 an additional input file runoff asc needs to be added Section 5 1 10 The changes that have been made are described in the following bulleted list Runoff and Run on coefficients are related to a new ASCII file Runoff asc Section 5 1 10 The model produces the locations of ponds in a file named pond out where the represents the grid number where ponds are located Section 6 2 5 The model reads from an input file named aspect dat the aspect directions at a user defined locations Section 5 9 5 A comment line and a flag is added to the input file input dat to include aspect correction
30. and the quantity of the supplied water in each month the transmission and field losses and the characteristics of the crop cultivated in this area The input data are explained in Table 16 Table 16 Number of irrigated months 7 Irrigation months 45678910 Supplied month MCM month 0 38 0 77 1 15 0 77 0 38 Transmission losses 0 15 irrigation per 1 15 1 15 Field losses 0 25 Runoff coefficient Grass area 0 6 Grass C value 0 3 Grass D value 0 6 Empirical constant 0 1 Details for file Irrigated Area dat Comment line Number of month when areas are irrigated Comment line The months when applied irrigation 1s Comment line Irrigation supplied in each month Comment line Losses caused by sewer leakages Comment line Losses caused by water leaving the soil Comment line Runoff coefficient for the grass part of the area Comment line The root constant C value for the grass area Comment line The wilting point D value for the grass area Comment line Relationship between AE and PE when SMD is between C and D 38 5 7 RUNOFF TO SURFACE WATER FEATURES 5 7 1 Runoff coefficients Since at least one geology type is considered in the study area at least one ROValues dat file should be available for the recharge model This file is related to Geology asc and gives the monthly variations of the runoff and the run on coefficients of the
31. arge method to reflect the findings of this experiment was developed this recharge method is called the wetting threshold method In the wetting threshold method the effective precipitation EP is calculated as the difference between rainfall and potential evaporation If EP is positive the rainfall value is larger that the potential evaporation and excess water is available to compensate the soil moisture deficit and to generate runoff and recharge First a wetting depth WD will develop from the ground surface downwards If this wetting depth exceeds a certain value water becomes available for runoff and recharge The maximum value that WD can reach is called the soil threshold ST ST is defined as the maximum amount of water that is absorbed by the soil before any runoff is generated Excess water in this case is calculated as the difference between WD and ST The maximum value WD can reach is equal to ST and the recharge and runoff are calculated as percentage of this excess water If EP is negative and WD is greater than zero it is assumed that water is freely available to evaporate and the SD value is set accordingly The calculation method is as follows 1 Calculation of the effective precipitation EP EP P PE 2 Calculation of the wetting depth WD If EP lt 0 WD WD ABS EP and WA 9 0 If EP gt 0 WD WD EP However if WD gt ST there is excess water EW given by EW WD ST and WD AT
32. arios can be represented mathematically as follows 1 Estimation of the actual evapotranspiration For SMD lt RAW or for In 2 PE then AE PE For TAW gt SMD gt RAW andIn lt PE then AE In K PE In where _ TAW SMD TAW RAW For SMD 2 TAW and In lt PE then AE In Ks 2 Soil moisture balance and calculation of potential recharge SMD SMD In AE If SMD lt 0 0 RECH SMD and SMD 0 0 2 2 4 Urban Areas Urbanisation provides an additional component of groundwater recharge generating from the loss of water from water supply and waste water pipes Rainfall recharge on the other hand decreases due to hardstandings and roofs which divert rainwater to drains All engineering practices aim to minimise the leakage from sewers but some unforeseen factors such as extra road loading etc may crack the sewers and result in unwanted losses The framework of recharge calculation in urbanised area is illustrated in Figure 6 and is summarised as follows The model assumes that urbanised areas constitute two parts The first is a paved or an impermeable part that represents roads and buildings The second is a green area that represents parks and domestically cultivated areas The percentage of the impermeable area is a user defined number and the percentage of the green area is determined accordingly Two sources of recharge water are identified in this case The first is recharge from water mains
33. array given in the file Plants asc The data array gives the percentage of crop type at each node There should be a number of data blocks that is equal to the sum of the number of SMD and FAO crops The sum of values extracted from all blocks at one location should total to 100 If there are more than one crop type and one block of data shows 100 of one crop at one location the other blocks should show zero at that location The first block of data corresponds to the first SMD crop type unless there are zero SMD crops If there are n SMD crops the n 1 block of data corresponds to the first FAO crop 33 5 5 SOIL Soil dat input file gives the characteristics of the considered soil type This file is related to Soil asc and gives the monthly variations of the soil threshold of the considered soil type information used by the application of the wetting threshold calculation method It also gives other characteristics such as the soil moisture contents at the field capacity at the wilting point and the depletion factor The latter information is used in the application of the FAO recharge calculation method The input data of this file are explained in Table 12 Table 12 Details for file Soil dat 15 0 Monthly wetting threshold values 15 0 15 0 15 0 15 0 15 0 15 0 15 0 15 0 15 0 15 0 15 0 Moisture content at field capacity Comment line 0 41 Value of the
34. co ordinates X then Y of the node followed by and the aspect direction 45 PART 3 Model output 6 Summary of output files produced by ZOODRM 6 1 THE PHILOSOPHY OF MODEL OUPUT The philosophy behind the structure of ZOODRM model output is to separate different types of data between files That is each file contains one specific type of information only This simplifies the post processing of model output and means that standard software packages can be used to interpret and visualise results All the output files have a very simple format and are easily examined using a text editor or processed using spreadsheet software The recharge model calculates recharge on a daily basis However regional groundwater flow models use stress periods that stretch over days or months and over which an average constant recharge values are applied A daily output of the recharge values is not needed in this case and the output from the recharge model can be produced in accordance with the used stress periods to reduce the size of the output files ZOOMQ3D also allows the use of stress periods that are smaller than one day However the availability of field data such as rainfall and evaporation data on a daily basis prevents the reduction of the stress period in the recharge model to less than one day This is the only case when the recharge model ZOODRM cannot be compatible with ZOOMQ3D Three types of output file are produced by the recharge model
35. considered geology type Please note that the product of the run on coefficient and the maximum cell length of the model must be less than one The input data of this file are explained in Table 17 Table 17 Details for file ROValues dat 0 00002 Runoff coefficient Dimensionless 0 00002 followed by the Run on Coefficient m for each month 0 00002 0 00002 0 00002 0 00002 0 00002 0 00002 0 00002 0 00002 0 00002 0 00002 39 5 7 2 Rivers River dat input file gives the information required by the River object to know the gauging location and the time when river flows are recorded by the model The input data of this file are explained in Table 18 Table 18 Details for file River dat Number of gauging stations Comment line 2 Total number of gauging stations where river flow will be recorded There should be at least one gauging station X and Y of gauging station nodes Comment line 297500 0 571500 0 The X and Y co ordinates of the 287500 0 576500 0 gauging stations Number of days at which to record river Comment line flows 1 The number of days at which you want to produce script files showing the flows at all river nodes Date to write river flows Day Month Comment line Year 31 01 1991 The dates of the above mentioned days Dates format is DD MM YYYY Number of river loss types Comment line 3 The number of river loss coefficients This is usually the number of geology type
36. d line window from the Windows start menu eeeee 15 Figure 8 Illustration of a gridded data set extending outside the boundary of the recharge mod l Eelere eege en eee RS AEO 24 TABLES Table 1 List of all ZOOMDRM input Deserteuren 18 Table2 ZOODRM input files which are relevant to model features eeeeceeeeeeeeeeeeees 20 Table3 Description of files eebe Ee eevee EE eee 22 Table A List of data files giving the spatial information of the study area 0 23 Table 5 Details of an ArcGIS exported file in ASCII format 00 0 ee eeeeeeeeeeeeseeeeeneeeees 24 Table 6 Details for file Rain grid dat lt icsscsccesnsestoccszesheenszeesteseenenuesacetauadagessccsavechedaeneneentenegh 27 Table 7 Explanation of the rainfall files giving the rainfall values at one rainfall station GE 28 Table 8 Details for file evapgrid dat eegene ee Ae 30 Table 9 Explanation of the evaporation file with extension txt giving the evaporation values at one evaporation station rd 31 Table 10 Explanation of the evaporation files with extension pe giving the evaporation values at one evaporation station essesssessseesssseessressersseessseessseessresseesseessseeesseesstesseesset 32 Tableti Details for file Plants dat eege ee 33 Table 12 Details for file Soil dat ergeet Eege Eege 34 Table 13 Details for file CDValues dat cecseeeeeeseeeseeseesersresreesresreseresreseseresresseseresresee 35 Table 14 Details for file Cro
37. de The distance between the unsaturated node and the spring is less than a specified value If an unsaturated node satisfies the above conditions for more than one spring it connects to the nearest spring PART 2 Model input 3 Running the model All that is required to install ZOODRM on a Windows PC is to copy the executable ZOODRM exe into a working directory No installation procedure is run in which ZOODRM program files are added to the system registry All the input files required by ZOODRM must be located in the same directory as the executable file All output files produced by ZOODRM will be created in the same directory as the executable file ZOODRM should be run from the command line in a MS DOS style box and not started from Windows Explorer In the event that an error occurs messages are written to the screen If ZOODRM is run from Explorer it may terminate before the user is able to read error messages To start a command window select Run from the Windows start menu and type either cmd or command in the drop down list box Figure 1 The user should then change directory to that of the working directory where the ZOODRM executable file is located To run the model type ZOODRM on the command line LS tx Type the name of a program folder document or Internet resource and Windows will open it For you Open cmd e Cancel Browse Figure 7 Starting a command line window f
38. e 1970 79 considered months of the considered years Year Month Value 1970 94 1970 Time should be within the time interval specified in Evapgrid dat E input file 1970 1970 1970 1970 1971 1971 1971 1971 1971 1971 31 Table 10 Explanation of the evaporation files with extension 7 pe giving the evaporation values at one evaporation station Glencaple Comment line giving the name of the evaporation station Jan 70 5 Evaporation values at each month of Feb 66 6 one typical year Mar 85 1 Apr 154 3 May 182 9 Jun 240 6 Jul 289 7 Aug 224 5 Sep 182 0 Oct 127 7 Nov 143 0 Dec 83 6 SA PLANTS Plants dat input file gives information about the crops considered in the area and the percentage of the area each crop occupies at one location The file starts with a flag that tells the model to use a majority plant type or to use the percentage plant type in case more than one plant type exists at one location The number of plants that require the use of the conventional SMD recharge calculation method is then set followed by the number of plants crops that require the application of the FAO recharge calculation method Blocks of data follow these lines The blocks of data are used if the calculation method flag is set to 1 i e several plant types are considered at one node of the model If the calculation method flag is set to 0 Le each model node has only one plant type these blocks of data can be ignored
39. e data array File that gives the ground surface elevation at each element of the data array This file defines if the recharge value calculated at one Recharge node is passed to and memorised at the Unsaturated node beneath it File allocates one reference number for urban areas if they exist at each element of the data array Spatial information files Additional files Plants asc Climate information files Evapgrid dat Must exist Raingrid dat Must exist yy dd mon asc or yyyy dd mon asc File that gives the crop type at each element of the data array The values of the data array are used if the majority landuse type is specified in plants dat This file with the data array must exist if SMD or FAO recharge calculation methods are used Need to specify explicitly that you are using these recharge calculation methods in Input dat File that allocates one reference number for a PE station at each element of the data array It also gives the names the record lengths and the evaporation long term averages of the PE stations This file gives a distribution of the evaporation long term average over the gridded area File required if rainfall is to be calculated from data recorded at rain stations File that allocates one reference number for a rain station at each data node It also gives the names the record lengths and the rainfall long term averages of the rain stations This file gives a distribution of the rainfal
40. e lost completely as recharge at a pond node 2 2 7 Springs Springs occur at locations where the water table intersects the ground surface The groundwater flow to springs is dependent on the hydraulic gradient the hydraulic conductivity of the aquifer material and the distance between the water source location and the spring It is extremely difficult to determine the groundwater movement within an aquifer and to determine the catchment related to a spring without the consideration of detailed geological and mathematical models Since it is not possible to include these features in a recharge model an alternative approach to represent springs has been found 13 It is assumed that part of the recharge flow that reaches an unsaturated node discharges at a spring providing that the unsaturated node is connected to the spring Springs are represented in the model as objects that are connected to the unsaturated node objects based on the following criteria 1 The ground elevation of the unsaturated node has to be higher than the elevation of the spring This ensures that the springs do not receive water from locations with ground elevations less than the spring elevation The spring connects only to unsaturated nodes that have specific geological and hydrogeological characteristics There is no topographical depression with ground elevation less than the spring elevation along the straight line that connects the spring to the unsaturated no
41. echarge model in such a case stems from the fact that the factors affecting the recharge calculations vary temporally and spatially at a regional scale In addition distributed recharge models enable the groundwater models to calculate heads and flows at the required point i e nodes for Finite Element and Finite Difference based models and for the appropriate time steps Hughes et al 2003 Estimates of recharge therefore have to be distributed in time and space A distributed recharge model has been developed for this purpose using object oriented techniques This model is called ZOODRM zoom object oriented distributed recharge model 1 2 WHY OBJECT ORIENTED APPROACH The model user is not directly affected by the approach used to develop the model The user s main interest is the functionality incorporated in the model to solve the problem under consideration The user is also interested in the ease and flexibility of processing the input and output data of the numerical model The functionality implemented in a numerical model could be sufficient for one specific application or may adequately represent the current understanding of recharge mechanisms in general This understanding however evolves with time and different approaches to represent a recharge mechanism may be developed In addition the mechanisms currently implemented in the model may not fulfil the user needs Under these circumstances the involvement of the user in the
42. he output supplied as monthly averages The recharge calculation is undertaken within a node object These node objects are held in turn within a grid object Any number of grids can be specified at whatever scale is required This facility was developed to provide input data in the correct form for ZOOMQ3D which incorporates local grid refinement in a Cartesian mesh Jackson 2001 Data are stored in separate objects for each data type e g rainfall potential evaporation etc The node object can then access data from the appropriate data object by sending its position X and Y co ordinates and time day month and year The data value for that position and time is then determined and returned to the node object Although both the data and the node objects are grid based each data grid is independent from each other and the nodal grid This ensures that the nodal grid can be changed without the need to recalculate the distribution of data nodes However if any of the data grids are coarser than the calculation grid then the nearest node in the data grid will be used The recharge model relies on data sets that are held within a GIS environment Most of the data which are exported from the GIS as ascii arrays i e grid files are directly read by the recharge model In some cases data has to be either processed using a spreadsheet or reorganised in a suitable format for the model to read An example of the latter case is the preparation of
43. hreshold value and other soil characteristics Section 5 5 Even if the SMD calculation method is used this file must exist and the values of the elements of the data array must be set to zero 5 1 7 The topography file Topography asc This file gives the ground surface elevation at each element of the grid This file is used for setting up the link between the spring nodes and the unsaturated nodes Section 2 2 7 however it must exist even if springs are not considered 5 1 8 The unsaturated map file UnsatMap asc This file defines if the recharge value calculated at one recharge node is passed to and stored at the unsaturated node beneath it Section 2 2 The values contained in the data array must be either 0 or 1 An Unsaturated node is created if the value returned from this file is equal to one If the unsaturated zone node is not created the recharge calculated at the recharge node above will be discarded 5 1 9 The urban areas file UrbanAreas asc The values of the data array are integers representing the IDs of the urban areas An ID of zero indicates the absence of urbanisation at the location defined by the array element For each urban area there should be a complementing data file called UrbanArea dat that gives its characteristics Section 5 6 4 Even if urban areas do not exist in the study area the data array of the ASCII file must exist and hold values of zero 5 1 10 The runoff
44. i VY Unsaturated water goes to thes j node m Recharge Unsaturated nodas H ai Ka Recharge 1 Spg total water Li reaching the Unsat node OH Crid nade D Spring discharges at P Spg total water Stop a river node reaching the Unsat node Unsaturated discharges at a spring node Spring node Spring node Recharge Stop River node Figure 2 Outline of the calculation procedure 2 2 1 SMD method The conventional method of estimating recharge in humid areas is based on the work of Penman 1948 and Grindley 1967 This method calculates the recharge as the excess quantity of water available from rainfall after taking the runoff the potential evaporation and the soil moisture deficit into account Runoff is assumed to take place instantly after rainfall and its quantity is estimated as a fraction of the amount of rainfall The potential evaporation is the maximum quantity of water that can evaporate under the given conditions of wind speed and solar radiation The Penman equation is usually used to determine the potential evaporation This equation includes the value of evaporation from grass covered soil with a freely available supply of water If the value of the potential evaporation is therefore greater than the quantity of water minus the quantity of runoff water will be lost from soil by evapo transpiration by plants However the quantity of water lost from soil is dependent on the Soil Moisture Deficit SMD which is the amount by
45. kal Survey NATURAL ENVIRONMENT RESEARCH COUNCIL User s manual for the distributed recharge model ZOODRM Groundwater Systems amp Water Quality Programme Internal Report IR 04 150 BRITISH GEOLOGICAL SURVEY GROUNDWATER SYSTEMS amp WATER QUALITY PROGRAMME INTERNAL REPORT IR 04 150 User s manual for the distributed recharge model ZOODRM M M Mansour and A G Hughes The National Grid and other Ordnance Survey data are used with the permission of the Controller of Her Majesty s Stationery Office Ordnance Survey licence number Licence No 100017897 2004 Keywords Distributed recharge model ZOODRM Bibliographical reference M M MANSOUR AND HUGHES A G 2004 User s manual for the distributed recharge model ZOODRM British Geological Survey Internal Report TR 04 150 61 pp 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 NERC 2004 All rights reserved Keyworth Nottingham British Geological Survey 2004 BRITISH GEOLOGICAL SURVEY
46. l long term average over the gridded area The model automatically can read grids of daily rainfall directly if available These files must be in ASCII format with the mentioned file name formats CDValues dat CropFAO dat Irrigated Area dat Spring dat ROValue dat Soil dat UrbanArea dat River dat Additional data files A set of evaporation files A set of rainfall files Model input files Must exist Clock dat Grids dat Input dat Output dat Plants dat Rechhydro dat Rivers dat BaseUnsatgrid dat Springdata dat Aspect dat Detailed input files Must exist if the related object is created File that gives the C D and the empirical factor values for each SMD crop object One file for each object File that gives the characteristics of each crop object One file for each object File that gives the characteristics of each irrigated area object One file for each object File that gives the characteristics of each spring object One file for each object File that gives the runoff and run on values for each soil type One file for each soil type File that gives the characteristics of each soil type One file for each soil type File that gives the characteristics of each urban area object One file for each object File that gives the characteristics of each river object One file for each object Files holding the data recorded at the evaporation stations File
47. model 21 5 Detailed description of input files ccccssssocssssssssssscsssssssesessessesssssssssssesssssesssaserssesees 23 OL Spatial Information EEN 23 Se Ce CN He 3 3 Potential E EE 30 S ER Eu CEET 32 SD EE EEN 34 5 6 Recharge calculation method eis ccicisscssasieisydcatsassiazaacadiacds sated ies Edert 35 5 7 Runoff AG surface water EE 39 5 8 Spring S erare iea EE E EEE E AARE E eines case EAEE ATE gea 41 SE EE ege Ehe 42 PART 3 Model Ot EE 46 6 Summary of output files produced by ZOODRM ssssssessscsssecesocesccescosessosesscessccesocesoossoo 46 6 1 The philosophy of model out 46 6 2 Recharge EE 47 References ssaisicissestadetisaeanyaseeeuasucesibisanesayenwcasssbnccend coca tan ustiaceassasanadenissuuibesattantabiacbsassantendabaceneesses 51 FIGURES Figure 1 Framework of the recharge model ssiccceseccdtacasecsstecciteadteeratvesterdtaratnvectneiaeagtieaense 4 Figure2 Outline of the calculation procedure esessseeseeeesessesessessseseresreserssresseseresresseseresees 6 Figure 3 Relationship between Actual Evaporation and Potential Evaporation 7 Figure A Relationship between Actual Evaporation and Potential Evaporation 10 Figure5 Diagram explaining the calculations of the Root depth Z the crop coefficient Ko and the Crop COVER EE 11 Figure 6 Recharge calculation for urbanised areas eesseseseseseeeeesersresresseesrrrreeseessesresee 12 Figure 7 Starting a comman
48. mporal information and other objects for managing the calculations and producing the results The main objects created in the current model are as follows e Calculation objects O ZOODRM model object that handles creation of all other objects time stepping and calculation of recharge via Grids CGrid object that holds CRecharge objects where recharge calculation takes place CUnsatGrid object that holds CUnsaturated objects and stores recharge calculated at each nodes CRecharge object where recharge calculation takes place CUnsaturated object where the effects of the unsaturated zones are taken into consideration CRiver object that determines how runoff is routed using slope aspect from a digital terrain model DTM and discharges the flow to the outside of the considered area CSpring object that holds spring flow information and calculates spring flows e Data objects o CRain inputs and stores rainfall on a grid basis and distributes via LTA rainfall or inputs information from a set of data files o CEvap inputs and stores Potential Evaporation PE on a grid basis o CGeology Stores information that are accessed by unsaturated node objects o CPlants create and organise information about Crop objects This object also stores landuse data o Col stores WT values and other soil information to be used by the application of the FAO recharge calculation method o CCrop st
49. objects the river node objects on the other hand are connected using a linked structure as if they represent one physical object while the spring node objects are independent of each other There are two layers of grid objects the upper grid holds the recharge node objects and overlays the second grid object which holds the unsaturated node objects Recharge nodes deal with objects that represent the land surface and the atmospheric characteristics of the area They can be allocated different types of land usage and given different types of recharge calculation using inheritance In principle any number of recharge node types can be specified Currently there are five types of recharge nodes which implement the following methods OI Soil moisture deficit recharge calculation ii A method incorporating crop water requirements and based on a concept developed by the UN Food and Agriculture Organisation FAO ii An arid zone accounting method iv A method that calculates recharge from urban areas and v A method that calculates recharge from irrigated areas The recharge node objects also interact with the river node objects to represent runoff and its discharge outside the area The unsaturated node objects are responsible for the movement of the infiltrated water in the unsaturated zone This is represented by either the communication of these nodes with the spring node objects i e passing water to them or by setting the delay
50. ores landuse data based on crop type Information held in this object are used if the SMD or the FAO recharge calculation methods are applied o CTopoMap stores the Land surface elevations o CAspectMap stores data for aspect directions at the recharge nodes e Other objects o CClock handles time step and updates date o COutput object that manages the output files of the models o CUrbanAreaGrid holds and create urban area objects o ClrrigatedAreaGrid holds and create irrigated area objects o CRechargeMap indicates which recharge method to apply This could be 1 for SMD 2 for WT or 5 for FAO recharge methods Irrigated and urban areas overwrite the information given here if they exist at the considered node location 2 2 KEY CONCEPTS The calculation of recharge within ZOODRM can be briefly summarised as follows at the beginning of each time step the calculations start at the recharge node level The recharge nodes request data from the data objects through Grid and ZOODRM objects The data are then processed by the recharge nodes which calculate the runoff and recharge values The runoff calculated at one recharge node is passed from one recharge node to another until it is delivered to the river node object The calculated recharge is passed directly to the unsaturated node object where it is split into two parts The first is passed to the spring object which if created discharges it to the corresponding rive
51. ovide links to the appropriate data files For example the file soil asc contains the areal distribution of soil types for the model and a file soil dat exists for each soil type If for example there are four soil types required by the model then the array within soil asc will contain a distribution of the numbers to 4 Combined with this data array will be four files named soil01 dat sol dat soil03 dat and sold dat These files contain the data required at the locations in the array with the relevant integer id Table 1 List of all ZOOMDRM input files Filename Spatial information files Must exist Aspect asc Geology asc Irrigated Areas asc Recharge asc Soil asc Topography asc UnsatMap asc UrbanAreas asc Description File that describes the direction of the ground surface at each element of the data array 1 for East 2 for North 3 for West and 4 for South File that gives the geology type at each element of the data array File that allocates one reference number for irrigated areas if they exist at each element of the data array File that gives the recharge calculation type at each element of the data array 1 for SMD calculation method 2 for WT calculation method and 5 for FAO calculation method To specify urban or irrigated areas recharge calculations the model uses automatically number 3 or 4 Do not use either number 3 or 4 in this file File that gives the soil type at each element of th
52. pFAOH dat Ae Ee ee e 36 Table 15 Details for file UrbanArea dat lt ccccicaieeciantgacedoti ac desteeiecinetaniceachialacaanieadds 37 Table 16 Details for file IrrigatedArea dat A 38 Table 17 Details for file ROValues H dat ecccesccececeeseenseccesscecenseecenseeceseeseneeecetteeee 39 Table 18 Details for file River dat iendeeegegieee t deier SeEe edd 40 Table 19 Details for file SpringData dat eelere eelere 41 Table 20 Details for file Spring dat s2cacccsescspecessaatgenszevgescassetesertovadenaseoesnnvetadaeeensens 41 Table 21 Table 22 Table 23 Table 24 Table 25 Details for fil Clock dat Aessen tesni iarria ii aea 42 D tails for file Input ET 42 Details7or file Outp t dat EE 43 Details fortile Rech yao at oferis a ee 44 Output files produced by ZOODRM eeceeccceceseeeeseececeeeeeseteeeeseeeenaeeeenaeeeeaaees 47 vi PART 1 Background 1 Introduction 1 1 WHY DISTRIBUTED RECHARGE An analysis of recharge i e the quantity of water that infiltrates from the land surface to the aquifer is an essential step in determining the resources of a groundwater system and simulation of flow in aquifers Recharge is a complex process but its quantification is important in order to understand the total water availability from an aquifer A groundwater model constructed to simulate groundwater flows in a regional aquifer is usually coupled with a distributed recharge model The need for a distributed r
53. produced at the end of each stress period Line that must exist even if no stress periods are used Is the runoff coefficient related to the Comment line rainfall intensity and SMD level 1 1 if yes and 0 if no Force aspect direction Comment line Y Y if yes and N if no 5 9 3 Output control file Because of the large size of the output file that can be produced by the model Output dat file is introduced to allow the production of some of the output files to be user defined The number and the coordinates of the nodes where the daily SMD variations are recorded and produced as time series are set in this file In Version 1 03 of the model gridded recharge values can be produced during a defined period of the simulation Two lines are added to Output dat to specify this period of time Table 23 shows the structure of this file Table 23 Details for file Output dat Write Daily River Flow Y for yes Comment line N Capital Y to write daily flow capital N if not Record Daily Flow At Gauging Stations Comment line Y for yes 43 Number of locations where daily SMD time series are produced 2 X and Y coordinates of nodes where SMD time series are produced 150000 110000 175000 112500 Start time for daily gridded recharge Capital Y to write daily flow capital N if not Comment line Number of locations where daily SMD time series are produced
54. r node object The second part is stored at the unsaturated nodes as recharge The total water calculated at the river nodes and resulting from the surface routing and spring flows is routed downstream and considered as the surface water flow It is assumed that the river objects loose part of this water to the unsaturated nodes which add this water to the recharge water already stored there The calculations stop at this stage and the total water calculated at the unsaturated node is then considered as the final recharge value at this time step Topographical depressions are considered as ponds The model determines these pond nodes based on the aspect map A river node overrides a pond node if they overlap The relationship between the calculation objects is illustrated in Figure 2 Summary Surface water movement and Ka Routing R O Excess water routing Water is lost at intermediate 2 Water Movement to the grid nodes based on an overland unsaturated zone loss coefficient Start 3 Water percolating to the unsaturated zone through eo Grid node stream beds River node 2 4 Groundwater movement a 1 R 0 Excess a towards springs water is moved to an Ze 5 Springs discharging at wadis unsaturated node o 6 Recharge H D s s s s 1 WL of river Se s D s s KL s D Ba mmm Surface water water moves to ki hovement the downstream E nodes d ZS sere Shei WL of river a K
55. ra Rf ra Lra X Rf RG 28 Where Rf Rainfall at required location Rf rc Rainfall at raingauge Rf ira Long term average rainfall at required location Rf rG Lra Long term average rainfall at raingauge The ideal would be a continuous daily rainfall record from the start of the model run to the end However some of the raingauges have significantly shorter record lengths but have to be used to provide the best possible geographical coverage of rainfall data To ensure a continuous distribution of rainfall when data do not exist then a substitute raingauge is used This is specified in the input file to the model Raingauges with short record lengths revert to a substitute raingauge If this raingauge has no data then a default raingauge is used 29 5 3 POTENTIAL EVAPORATION Evapgrid dat is the file that sets the evaporation conditions of the area This file includes two arrays The first array gives the distribution of the zones that are related to the evaporation stations and are determined based on the Theissen polygons The second array gives the distribution of long term average evaporation Table 8 gives a line by line explanation of the information included in it Table 8 Details for file evapgrid dat 1000 1000 Mesh spacing in the X direction Ax Mesh spacing in the Y direction Ay Number of columns of the data array Number of rows of the data array 287000 588000 X followed by the Y co ordinates of the lo
56. rainfall during the wet season a specified quantity of water during the dry season But unlike the SMD recharge nodes there is only one crop object associated with each irrigated area with one root constant value C and one wilting point value D During the wet season the SMD recharge calculation method is applied During the dry season it is assumed that a fixed percentage of the applied water representing the transmission losses infiltrates directly to the unsaturated zone The remaining water is then split into two parts The first is the runoff water which is routed to the nearest river node based on the aspect direction map and the SMD recharge process is applied to the second part to calculate the amount of water that infiltrates to the unsaturated zone 2 2 6 Routing to Rivers The amount of flow in the river branches is partly controlled by the runoff coefficients that are allocated to the recharge nodes The Runoff coefficient can be varied on a monthly basis or can be related to the soil conditions The relationship between the runoff coefficient rainfall intensity and current soil moisture deficit developed by Rushton 2003 for cultivated sandy soil overlying sandstone aquifer is hard coded in the model The runoff coefficient represents the percentage of the rainfall to be routed to the rivers The routing procedure is based on an aspect map created in a GIS environment This map indicates the direction of the slope of the ground
57. rom the Windows start menu 4 Summary of input files required by ZOODRM 4 1 THE PHILOSOPHY OF MODEL INPUT The philosophy behind the structure of ZOODRM model input is to separate different types of data between files That is each file contains one specific type of information only Whilst this results in the model requiring many input files compared to other models they all have a very simple format and are easily modified using a text editor The following points should be recalled when modifying ZOODRM input files 1 Values are read into the model in Tree format and consequently the user does not need to ensure that the number of decimal places and field width are correct for each input value contained in each file 2 The correct number of parameters must be entered on the correct line of an input file 3 Whilst it does not matter whether the user enters a decimal number as an integer it is not permissible to enter an integer as a decimal number 4 Some but not all files contain comment lines These are text strings which are read by the model and discarded 5 The maximum length of a comment line is 128 characters 6 Itis good practice but not necessary to remove white space from the end of lines 7 Comments cannot be appended to the end of lines of data If these are included the model will crash 8 Comments can be appended to the ends of files 9 The names of all files are fixed except where defined in datafiles
58. ropFA O dat Number of crop harvests per year 1 Initial crop coefficient 1 15 Mid crop coefficient 0 95 End crop coefficient 0 85 Minimum root depth m 1 0 Maximum root depth m 1 0 Depletion factor 0 7 Minimum percentage cover 100 Maximum percentage cover 100 Season 1 Harvest month 10 Typical drilling month 11 Emergence month 3 100 crop cover month 5 Senescence begins month 9 5 6 4 Urban recharge Comment line Number of times the crop is harvested per year Comment line Initial crop coefficient Comment line Mid crop coefficient Comment line End crop coefficient Comment line Minimum root depth Comment line Maximum root depth Comment line Depletion factor Comment line Minimum percentage cover Comment line Maximum percentage cover Block of information repeated for each harvest season in one year The Harvest time the typical drilling time the emergence period time when crop covers 100 of the area and time when senescence begins are given here The difference between the harvest time of the first season and the time when senescence begins of the last season should not exceed 12 months The UrbanArea dat input file is required if urban areas exist in the study area This file gives the characteristics of the urban area such as the daily flow supplied to the urban area the losses from the pressurised water mains and sewers the percentage of
59. run on file Runoff asc The values of the data array of this file are integers representing the IDs of different zone types For each zone runoff and run on coefficients are specified in files named ROValues dat Section 5 7 If there are N zones a set of N files named ROValuesN dat must exist where N is a two digit integer 01 to 99 At least one runoff run on zone type must be defined 5 2 RAINFALL There are two options to set the rainfall conditions of the study area This is by either reading rainfall data at specified rain gauges and distributing them using the Theissen polygons or by preparing the distributed rainfall outside the recharge model environment writing them into files and allowing the recharge model to read these files In the first case Raingrid dat data file is used however in the second case both Raingrid dat and either mon asc or H H mon asc data files are used Where mon asc and mon asc are ASCII data files and the represents a number The and of the first and second file types give the year followed by the day of the considered date in the format yy dd and yyyy dd year day respectively 26 By default the model will assume that the daily rainfall is calculated using the rain gauge data and Theissen polygons and opens Raingrid dat A line by line explanation of this file is given in Table 6 If the number of raingauges is set to zero the model switches
60. s but it could be different However it is safer to set this number to the number of geology types River loss corresponding to each Two comment lines GeoCode Geocode RiverLoss 10 0 01 The river loss coefficient for each 11 0 01 geology type the river may run over 12 0 01 The geology types that the river nodes may have should be covered here So a river may have three related geology types and these could geology types 10 11 and 12 10 11 and 12 should be mentioned in this case with the associated loss coefficient 40 5 8 SPRINGS SpringData dat input file is required to create the spring objects It gives the number of springs their co ordinates and ground elevations and the co ordinates of the stream nodes to which they discharge their flows The structure of this file is explained in Table 19 Table 19 Details for file SpringData dat Number of Springs Comment line 3 Total number of springs Coordinates X Y Z MaxDistance Comment line NbrLinkedGeology Related stream node X Y 298000 580000 10 5000 2 300500 Each line gives information about 975500 one spring These are 159000 155000 324 5000 3 159000 _ the coordinates of the spring X Y and Z the radius of the area encircling the spring and where recharge nodes can be connected to the spring the number of geology types that the spring can connect to the co ordinates X and Y of the stream node where the spring
61. s holding the data recorded at the rainfall stations File to set the start and end simulation times File created by ZETUP ZOOMQ3D and read directly by the recharge model File needed to specify if the recharge node grid shapes are different from the unsaturated node grid shapes File to set the required model output files File to specify the crop types at the data nodes File to specify the location where the variation of recharge with time is recorded File created by ZETUP ZOOMQ3D and read directly by the recharge model File that must exist if the upper recharge grid is different from the lower unsaturated grid ZETUP ZOOMQ3D can be used to create a data file representing the unsaturated grid Grids dat file must be renamed as BaseUnsatgrid dat in this case File that gives the number of spring and specific information about each spring File that gives the locations of the nodes where a user defined aspect directions are set Table 2 ZOODRM input files which are relevant to model features Model feature Relevant file names Relevant section Grid structure Grids dat structure of model grids provided by ZETUP 4 2 Recharge calculation node type Recharge asc sets recharge node type from 1 to 5 5 1 Unsaturated zone nodes BaseUnsatgrid dat structure of unsaturated zone grids 4 2 Input dat matching groundwater and surface water catchments Unsaturated grid with no calculation UnsatMap asc
62. s to produce the results at the end of stress periods the lengths of which are user defined In the second option the user has to specify the number of stress periods per block If the length of simulation time is greater than the block length the stress periods will be repeated from the beginning as defined by the user Table 22 shows the structure of this file Table 22 Details for file Input dat Are you using the SMD or FAO recharge Comment line calculation method Y for yes and N for no If Y needs include plants dat and plants asc Y Capital Y if the SMD or FAO recharge calculation methods are used If Y include plants dat and plants asc data files Is Unsaturated grid different from the Comment line recharge grid Y for yes and N for no 42 Capital Y if the base unsaturated node grid is different from the base recharge node grid Capital N if not Use user defined stress periods Comment line Y Capital Y if user defined stress periods are used and capital N if monthly stress periods are used Number of stress periods per block Comment line that must exist even if no stress periods are used Number of stress periods per block Line that must exist even if no stress periods are used Stress period lengths Multiple of days Comment line that must exist even if no stress periods are used 73 73 73 73 73 Number of days in each stress period The recharge values will be
63. selected nodes representing the groundwater catchment It is possible to introduce simplifications in the recharge modelling approach so that the surface area outside the groundwater area is ignored and distributed recharge calculations are undertaken only over the groundwater catchment However the use of two levels of calculation grids in ZOODRM solves this problem by allowing a complete representation of the surface catchment while at the same time producing results over an area defined by the groundwater catchment The recharge grid is the first calculation grid level in the recharge model This grid can be made to fit the whole surface water catchment area while the second grid level the unsaturated calculation grid can be built so it represents the size and extent of the groundwater catchment Any grid refinement however should fall within the groundwater catchment limits If this approach is used the two input files rivers dat and grids dat should be prepared using ZETUP and represent the whole surface water catchment The grids dat file used to build the groundwater model should be also available for the recharge model but renamed as BaseUnsatGrid dat This file will produce an unsaturated grid having a size similar to that of the groundwater model grid The ASCII file Recharge asc which is used to specify the type of recharge calculation method at a specified node can be also used to control the creation of the recharge nodes This file has
64. surface at each recharge node The runoff water is moved from one node to the adjacent one based on this direction When a recharge node that is connected to a river node is reached the river flow at this node is incremented by the amount of the runoff flow It is assumed that the runoff flow generated at one node diminishes in quantity before moving to the next node In the recharge model this is represented by an overland loss factor which is defined as the fraction of the runoff water generated from one node and lost over another Figure 2 This factor called run on in the model depends on the physical characteristics of the rocks or the soils over which the water is moving and is defined as the loss of water per metre length i e this factor has a unit of m Water loss is therefore dependent on the distance travelled by the runoff within a surface water catchment It should be noted that the product of run on coefficient and the maximum cell length in the model must be less than one The total run on flow calculated at one node during one time step is considered at the next time step i e the next day and is added to the rainfall amount of the next time step Topographical depressions are considered as ponds The model determines these pond nodes based on the aspect map The surface water routing can be interrupted and may not reach the river node if a pond node exists between the two nodes The surface water routed from one recharge node will b
65. the impermeable area etc The input data are explained in Table 15 36 Table 15 Flow in PWM m d 12055 Losses from PWM 0 3 Flow in sewers m d 12055 Losses from sewers 0 15 Impermeable area 0 8 Runoff coefficient Impermeable area 0 9 Runoff coefficient Grass area 0 4 Grass C value 0 3 Grass D value 0 6 Empirical constant 0 1 Position of river node X Coord and Y coord 151877 192057 Details for file UrbanArea dat Comment line Total flow supplied for the urban area Comment line Percentage loss from the pressurised water mains Comment line Total flow in all sewers Comment line Percentage loss from the pressurised water mains Comment line Percentage of the impermeable area Comment line Runoff coefficient for impermeable part of the area the Comment line Runoff coefficient for the grass part of the area Comment line The root constant C value for the grass area Comment line The wilting point D value for the grass area Comment line Relationship between AE and PE when SMD is between C and D Comment line The X and Y co ordinates of the river node at which the sewers of the urban area discharges 37 5 6 5 Irrigated area losses The IrrigatedArea dat input file is required if irrigated areas exist in the study area This file gives the characteristics of the irrigated area such as the number of irrigation months
66. the surface soil layer that is subject to drying by evaporation The permanent wilting point is multiplied by a factor of 0 5 because it is assumed that the evaporation can dry the soil to mid way between the wilting point and oven dry Crop stressed 1 0 Ks 0 5 S gt Gei lt 0 0 Soil moisture deficit or root zone depletion mm After EA 2002 Figure 4 Relationship between Actual Evaporation and Potential Evaporation The crop coefficient K the root depth Z and the percentage crop cover Max Cover change based on the crop growth status The times at which the crop goes from one status to another have to be specified In the current method these times are the harvest time the drilling time the time when crop starts to emerge the time when the crop covers 100 of the area and the time when senescence begins The above three factors are then determined knowing the current time as explained in the diagram of Figure 5 Cover Value A n on ke W I be oO o oO E Q gt gt 6 oi g Q D gt ed D Si Ke H oQ O e o 2 5 SS 2 S T o oO 5 oi es E En KE Wi o o g P A m Figure 5 Diagram explaining the calculations of the Root depth Z the crop coefficient K and the crop cover where Cover Value A Covermax Covermax Cove 3 Ga E x Cover Value B Covermax Covermax Cover p 2 3 and Z Value Ass Zum Z Zoea NE rmin rmax rmin The different recharge scen
67. time that may occur in this zone In addition to the recharge calculation objects there are data objects which hold distributed atmospheric and land information The data objects read data on grids that area independent of the calculation grids enabling the model size to be changed without the need to alter the data grids These data objects represent for example topography geology landuse rainfall and evaporation 14 TERMINOLOGY ZOODRM is written using an object oriented programming language Whilst the users do not need to concern themselves with what this means the term object is used a number of times within this manual and consequently a brief explanation is required The user can think of an object in abstract terms as any distinct entity that stores data and perform tasks In ZOODRM objects are defined to represent real world features For example the soil zone is represented by an object 1 5 UNIT CONVENTION All lengths in ZOOMDRM must be specified in metres The unit of time is specified as days Parameters representing the plants and ground characteristics are in mm Rainfall rates are defined in mm day when input and potential evaporation defined as mm month 2 Modelling approach and key concepts 2 1 OBJECT FRAMEWORK The distributed recharge model requires that the recharge calculations are undertaken at the appropriate points over the study area A daily time step is used for the recharge calculation with t
68. ur directions The values of the data array must therefore be integer values ranging from 1 to 4 A value of 1 indicates a ground surface inclination towards the North while the values 2 3 and 4 indicates ground surface inclination towards the East South and West respectively If this file is generated from a Digital Terrain Model DTM in an ArcView environment you need to reclassify the generated data as follows 135 A 45 Old values Degrees New values N 315 360 0 45 1 45 135 2 SS S 135 225 3 225 315 4 225 315 3 5 1 2 The geology file Geology asc The values of the data array of this file are integers representing the IDs of the geology types The geology type affects the amount of water lost from the River nodes to the Unsaturated nodes Section 5 7 2 and the connections between the Unsaturated nodes and Spring nodes Section 5 8 At least one geology type must be defined 5 1 3 The irrigated areas file IrrigatedAreas asc The values of the data array are integers representing the IDs of the irrigated areas with an ID of zero indicating the absence of irrigation at the location defined by the array element For each irrigated area there should be a corresponding data file called IrrigatedArea dat that gives its characteristics Section 5 6 5 Even if irrigated areas do not exist in the modelled area the data array of the ASCII file must exist and hold values of zero 5 1 4 The
69. wer left corner 2 Number of PE station data to be read 1 1 999 1 1970 9 2003 Evaporation station id MORECS_SQ70 txt Substitute station id 11999 1 1970 9 2003 Dummy pe LTA evaporation Start month Start year End month End year Name of file to be read 11111111111111 1 Grid of distribution of Theissen polygon 11 11 11 11 11 11 11 11 LTAFactor LTAFactor 1 5 Multiplier for LTA values This factor multiplies the LTA values given in the block of data given next to produce the actual value of LTA evaporation 1 02 1 02 1 04 1 04 1 07 1 08 1 08 Grid of distribution of LTA values 1 05 1 05 1 04 1 04 1 03 1 03 1 04 1 04 1 09 1 09 1 08 1 04 1 04 1 04 1 04 30 The evaporation files should have the pe or the txt extension The reason for this is that the recharge model can read the evaporation information as a monthly time series or as a repeated pattern of monthly averages If the evaporation file has a txt extension the recharge model assumes a monthly evaporation input data and reads from a file having the format shown in Table 9 If the evaporation file has a pe extension the recharge model assumes a average monthly evaporation input data and reads from a file with the format shown in Table 10 Table 9 Explanation of the evaporation file with extension txt giving the evaporation values at one evaporation station YEAR MONTH PE Comment line 1970 48 5 Evaporation values at th
70. xist for the model to run even in the case when no irrigated or urban areas are considered in the study IrrigatedAreas asc and UrbanAreas asc in this case represent a certain areal extent that covers the study area but all the values in the array will be zero An example of the ASCII ArcGIS exported files is presented in Table 5 Table 4 List of data files giving the spatial information of the study area Aspect asc Geology asc IrrigatedAreas asc Plants asc Recharge asc Soil asc Topography asc UnsatMap asc UrbanAreas asc 23 Table 5 Details of an ArcGIS exported file in ASCII format ncols 577 Number of columns in the array nrows 503 Number of rows in the array xllcorner 285405 072581 Lower left corner of the gridded area yllcorner 562693 194889 Upper left corner of the gridded area cellsize 50 Cell size NODATA_value 9999 If 9999 is shown in the array of data no information is found at the node location while gridding An array of data showing nodal 11112222222211111 codes 11112222222211111 11112222222211111 11112222222233333 11122222223333333 11222223333333333 22222233333333333 Figure 8 Illustration of a gridded data set extending outside the boundary of the recharge model grid 24 5 1 1 The aspect file Aspectasc This file describes the direction of the ground surface at each element of the data array used in surface water routing to rivers Section 2 2 6 The model accepts only fo
71. y Qn is the flow MI day cumulated at the n river node in one day 6 2 2 River flow accretion profiles River flow accretion data are written to the output file FlowRiver out where represents the spring number for example 01 The river flows cumulated at each river node are produced on a daily basis To allow an easy plot of the produced results the file gives flow results MI day at nodes grouped based on the stream number they represent The distance between the considered node and its adjacent upstream one is also given for this reason The output file gives the stream number first followed by the date when the results are recorded followed by a comment line describing the numbers produced on the subsequent lines This format is explained next Stream Number 1 17171970 X Y Reach Flow 293000 575500 0 0 Qez 293500 576000 707 107 0 55 Stream Number 2 1 1 1970 X Y Reach Flow 292000 578000 0 0 Oeil 292500 578000 500 1 03 48 where X Yare the x and y coordinates of the river node Reach is the distance between the considered node and its upstream one F Low is the cumulative flow recorded at the river node 6 2 3 Spring flows Spring flows are written to the output file FlowAtSpring out where represents the river number for example 01 The produced file gives the time elapsed in days from the start of the simulation and the corresponding flow in mm dax The unsaturated zone water produced at
72. y semi arid Mediterranean hillslope Hydrological Processes vol 17 pp 279 296 PENMAN HL 1948 Natural evaporation from open water bare soil and grass Proc R Soc London Ser A 193 pp 120 145 RUSHTON KR 2000 Recharge estimation for British aquifers A review by Ken Rushton Environment Agency internal document RUSHTON KR 2003 Groundwater hydrology Conceptual and computational models John Wiley amp Sons Ltd The Atrium Southern Gate Chichester England SPINK AEF JACKSON CR HUGHES AG and HULME PJ 2003 The benefits of object oriented modelling demonstrated through the development of a regional groundwater model MODFLOW and more 2003 Understanding through modelling Conference proceedings International Ground Water Modeling Center IGWMC Colorado USA 51

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