Run SWAT Model

In the next sections, are described the needed steps to be taken in order to perform a SWAT simulation whether using ArcView or MapWindow software.

For ArcView users

SWAT Project and first simulation with default parameters

Create the SWAT Project

1. Run ArcView
2. If a Window appears "Welcome to ArcView GIS" asking to create a new view, click "Cancel"
3. Go to menu "File"->"Extensions"
4. Click on the check box "AVSWATX extendable" and NEVER click the check box "Make Default"
5. 

   ArcView SWAT extension
6. Go to Explorer and create a directory for the project (e.g. Aplica\AVSWAT2005\Portugal\Guadiana\BaciaExemplo\Cenario_teste)
7. A new Window appears - SWAT interface. Click on the box "New Project" to create a new project.
8. Choose the name for the project in the directory you created (e.g. Bacia_crsr)
9. Go back to Explorer and to your project directory (the just created by the project) and copy the "data" file from \\Datacenter\Albufeiras_Eutrofizacao\ComoFazer\1.PreparaInputs\3.SWAT\ExemploAplicacao\data
10. A window appears "SWAT - ArcView: DataSets". Choose the data directory just created and named "data".

Create the project options text file

Copy from \\Datacenter\Albufeiras_Eutrofizacao\ComoFazer\1.PreparaInputs\3.SWAT\ExemploAplicacao\SimulationProperties_xxx.txt the text file where you will write all the options that you make in this interface. This file is not used by the model, it is only a memo and will be very useful when you have a lot of old simulations and have to understand what options have you chosen and difference betwen them.

Place the file in the ..\watershed\text folder that meanwhile was created by SWAT.

Watershed Delineation

A window appears "Watershed delineation".

ArcView SWAT watershed delineation

In Dem Setup

Remind to write down relevant information to your memo file. Follow the example file that you copied previously (project options text file)

1. Click the folder icon to open the DEM (digital elevation model), choose to open from disk and select the DEM in the folder data\dem.
2. If you do not have yet the DEM go to Get NASA DEM for SWAT
3. Click Properties button
4. Click Projection button
5. Message "Undefined Projection". Click "OK"
6. Message "Do you want to modify your projection?". Click "YES"
7. Click "Custom Projection" button
8. "Projection Properties" window. Select radio buttom "Custom"
9. On "Projection" choose "Transverse Mercator"
10. On "Spheroid" choose "Internation 1909"
11. Write the coordinate settings in the next picture so that the final it should look like this:
12. 

    ArcView SWAT projection
13. Click "OK" twice.
14. Back to "Dem Setup" click "Apply" button
15. Message "Do you want the edge cells to flow inside?" Choose "No"
16. Message "End of processing". Click "OK"

In Stream Definition

Remind to write down relevant information to your memo file. Follow the example file that you copied previously (project options text file)

1. Choose the treshold area for the consideration of a stream line. The value depends on the number of subsbasins generated. As you only will know the exact number of subbasins after completing the Watershed Delineation step, as a first value put in the recommended. Then, in the end of the Watershed Delineation step you should have around 50-80 subbasins; if you have less you shoul decrease the treshold area, if you have more, you should increase.
2. Click "Apply"
3. When the process is finished, streams will show up in the background

Outlet and Inlet Definition

Remind to write down relevant information to your memo file. Follow the example file that you copied previously (project options text file)

Outlets are places where the model will produce outputs (flow, concentrations), so you should have an outlet in the reservoir wall and in the river monitoring points from INAG (to validate model results)

Inlets are inputs from point sources (e.g. WWTP or industrial sources). If running with point sources see SWAT - Add Point Sources Location how to add the location of point sources loads.

1. If there is not already an outlet where you whish to have one, add the outlets leaving the radio button on "Outlet" and clicking on "Add". Choose where to add the point. Hint: Use the reservoir shape to know where to locate the downstream watershed outlet (at the reservoir wall so that all drainage area is considered).
2. After adding all needed outlets, select the outlet which is the watershed outlet (downstream outlet), clicking first on "Select button" and then pointing at the outlet (or selecting an area where that is the only outlet inside).
3. Click "yes" to confirm that you selected one outlet.
4. The model generates the watershed and subbasins, then click "Apply" so the model computes the parameters for each subbasin generated.
5. Message window saying that the computation was completed. Click "OK"

Land Use and Soil Definition

1. Add to the ArcView the shapes with the soil data (in data/soil) and land use (in data/uso_solo)
2. Go to Menu "AVSWAT" -> "Land Use and Soil Definition". Note that the previous step (watershed delineation) is in this menu and that the next step is unavailable yet.

In "Land Use Data Layer"

1. Click the folder icon to load the land use shape.
2. Choose option: Select shape from watershed view
3. Choose option: Format: shape
4. Select shape: Corine2000
5. Select the field with the land use code: code_00
6. Message saying that shape was sucessfully clipped and to reclassify. Click "OK"
7. Now we need to translate the land use codes to a land use that SWAT understands. That is done by a table with correspondences. Click "Lookup Table Grid..." button.
8. Select: "User Table"
9. Select: dbf file
10. Browse for the file lucnew_wwater.dbf in data/uso_solo
11. Now land uses in swat language appear. Check that all the values in the table have an "Land Use SWAT" code.
12. Click Reclassify

In "Soil Data Layer"

First you need to copy from SAMSUNG the file "usersoil.dbf" from "C:\AVSWATX\AVSWATDB" to your local folder "C:\AVSWATX\AVSWATDB". This file has the soil names (and hydraulic parameters associated) that you will have in the soil map.

1. Load the soil map to the view: Click on the main menu icon "load theme" then select the folder and file data/solo/solo_eu_portugal.shp. This will load the theme in the theme view in ArcView.
2. Then, in the "Avswatx"--> "Land Use and Soil Definition" --> "Soil Data Layer" panel, click the folder icon to load the soil shape.
3. Choose option: Select shape from watershed view
4. Choose option: Format: shape
5. Select shape: Solo_eu_Portugal
6. Select the field with the land use code: sltxcl
7. Message saying that shape was sucessfully clipped and to reclassify. Click "OK"
8. Now we need to translate the land use codes to a land use that SWAT understands. That is done by a table with correspondences. Click "Lookup Table Grid..." button.
9. Select: dbf file
10. Browse for the file soil_crsr.dbf in data/solo
11. Now soil types in swat language appear. Check that all the values in the table have an "Name" code.
12. Click Reclassify

_____

1. Click "Overlay" where model takes out landuse and soil infor for each subbasin.
2. Message saying that process is complete. Click "OK".
3. This is how it should look like the window after all done:

ArcView SWAT Land Use and Soil definition

Definition of HRU

HRU (Hidrological response unit) is a uniform area with the same land use and soil type. It is over these that the model will make the hydraulic and WQ computations. One sub-basin may have one HRU (and the sub-basin will inherit the major land use and major soil type of the sub-basin) which can be a coarser aproximation, or can have multiple HRU's. HRU's do not have georeferenced information, they area areas inside a subbasin with one land use and one soil type.

This is a text phase where you will try to see if one HRU per sub-basin is enough to describe your complete watershed land use and soil distibutions; if not increase the number of HRU.

1. First try to have only one HRU per sub-basin (select dominant land use and click ok)
2. Click "OK" twice to proceed
3. Check on menu "Reports"->"Show List" the original land use and soil type area percentages inside your watershed in "SWAT model Land Use and Soil Distribution" text. Compare these values with the ones generated with your HRU definition (in this case one HRU to one sub-basin in "SWAT model Land Use and Soil Distribution (after treshold application)". The difference between percentages of land use and/or soil shoul not be as higher than 2-3%. If higher, you need to repeat the HRU definition process to have more HRU's.
4. If needing more HRU, go back to menu "Window"->"Watershed" and then in menu "AVSWAT"->"HRU distribution" select "Multiple Hydrologic Response Units".
5. Two ruler appears one for land use and other to soil. Usullay only land use has high variability comparing to sub-basin sizes (see shapes created by the model) so we only need to move the land use ruler. Try 20% and the click "OK"
6. Click "OK" twice to proceed
7. Do the same checking again comparing percentages from land use and soil maps with your model definition. If still the difference is not inside 2-3% have to get more HRU and repeat process.

What means 20% and 10% Land Use tresholds for HRU definition? It means that SWAT will produce an HRU if inside the sub-basin there is one land use area bigger than 20% the total sub-basin area, meaning that ignores land uses that have areas less than that percentage. The same rational for 10%.

Weather and write default parameters

1. You will need to Get Rain For SWAT
2. Create a new (new excel file in office 2003 then save to .dbf) file based on ".\data\weather\LocRain.dbf" and leave the same file name. This file points to the precipitation stations, so substitute (or add if more stations) coordinates and station names. Remind to use a short name for station names and it has to be the same names as the dbf's where precipitation were written in the previous step. Station coordinates may be obtained in SNIRH -->"meteorologia"-->"dados base"-->"Caracteristicas das estações".
3. Copy from SAMSUNG file "userwgn.dbf" from "C:\AVSWATX\AVSWATDB" to your local folder "C:\AVSWATX\AVSWATDB".
4. Edit the file in ".\data\weather\LocWgn.dbf" with the name and coordinates of the station(s) near to your watershed.

This file points to weather stations that will create climate variables (wind, humidity, etc..) so you should check which is closer to your watershed using the weather stations shapefile in \\datacenter\Albufeiras_Eutrofizacao\Produtos\ProjectosGIS\ShapesBase\EM_WGNSWAT_PT. Station name is in this shape file and coordinates in the file "C:\AVSWATX\AVSWATDB\userwgn.dbf" searching for station name. Please remind to use a station with no data fails in file userwgn.dbf.

1. Go to menu "AVSWAT"->"SWAT View" then menu "Input"->"Weather Stations"
2. "Rainfall data" --> "Raingages" --> "Locations Table" [browse] and choose file ".\data\weather\LocRain.dbf"
3. "Weather simulation data" --> "Custom database" --> "Locations table" [browse] and choose file ".\data\weather\LocWgn.dbf"
4. Click "Ok".
5. Substitute file ".\watershed\tables\PCP.dbf" all values -99. by adequate values of precipitation (they should not appear as noted in the first step).
6. "input"-->"build all default"-->"yes"-->"continue".
7. First window "no"
8. Second window "no"
9. Third window "yes"
10. Ok

Run SWAT in the Interface

1. "Simulation"-->"RunSwat"
2. Click on "Bsn" button...
3. Change the "Potential ET Method" to "Pennman-Monteith method".
4. "Setup SWAT Run"
5. "Run SWAT".
6. Everything should run fine. Most errors should occur from bad formatting and/or bad data in the dbf input data files. The precipitation file and the LocWgn and LocRain files.
7. You may not wait until the end of SWAT simulation and close the run window. This is because SWAT run in its original form creates giant and confuse outputs so there has been created a MOHID version of SWAT. This version runs the original code of SWAT bur produces output in MOHID language (e.g. timeseries that can be read in Timeserie Editor or be used as discharges in MOHID). See next step to know what to do to have your outputs in MOHID way.

Using a modified SWAT executable to produce outputs in MOHID format

We are not interested in running in the interface (the previous step was just to see that it runs) because the output files are giant so everytime a change is made in the interface it is needed to run in the folder structure explained in the link below. Each new run with changes has to create a new folder structure and run it using the input files from the interface. To obtain outputs in a format that suits our needs see the steps in Run SWAT with MOHID outputs.

Run SWAT with common calibrations

The commom calibrations are in groundwater, soil, and management files. The first callibration affects flow and the other two affect water quality.

Just need to change some parameters in the SWAT interface, make a new simulation structure and rerun the model in to that structure so that you will have two simulations (the first, default parameters, and the second with parameters more fitted in to our watershed reality).

In Menu >Edit Input >SubBasins Data

By default the first HRU is selected (number, land use, soil are presented and selected)

1) Groundwater

Lets change in all HRU's the hydraulic response of soil to feed the river (groundwater or baseflow)

1. Click the .gw
2. Change GW_DELAY to 3 days
3. Change ALPHA_BF to 1 days
4. Click OK
5. In >LandUses select radio button to >selected and select all the land uses of your project (old down shift and click to multiple selections)
6. In >Soils select radio button to selected and select all the soils of your project (old down shift and click to multiple selections)

It should look like something like this:

ArcView SWAT GW parameter change

1. Click OK to apply it to all the HRU's

2) Soil Erodibility

Lets change in all HRU's the soil erodibility. Attention that it has to be applied for each soil type at a time!! - just follow instructions

Have to find one HRU for each soil type that exists in the watershed. These HRU's will apply its configuration to all other with the same soil type.

Do the next steps for each soil type (and HRU representing that soil type):

1. Click the .sol
2. Change USLE_K to 0.3 (originally is 0.1)
3. Click OK
4. In >LandUses select radio button to >selected and select all the land uses of your project (old down shift and click to multiple selections)
5. In >Soils do not do anything! It will apply those settings to all land uses with only that soil type.

It should look like something like this:

ArcView SWAT Soil parameter change

1. Click OK to apply it to all the HRU's with that soil
2. Do not forget to select now other HRU with a differente soil type. Do this steps until all soil types are covered.

3) Autofertilization

Lets put the autofertilization in all HRU's. Attention that it has to be applied for each soil type and each land use at a time!! - just follow instructions

Autofertilization is disconnected by default we will put the parameters for autofertilization thar are in the manual in the agricultural land uses.

Have to find all the agriculture crops (e.g. AGRC, AGRR, ORCD, RICE...) and select one HRU for each land use (only agricultural) and soil type that exists in the watershed. These HRU's will apply its configuration to all other with the same land use and soil type. Do the next steps for each land use (agricultural) and soil type (and HRU representing that configuration):

1. Click the .mgt
2. Double click >Auto fetilization init
3. Change >fertilizer to 28-10-10 - it is a standard fertilizer (28%N, 10%P, 10%K)
4. Change >AUTO_NSTRS to 0.93 - it is the treshold of the plant stress to start applying fertilizer
5. Change >AUTO_NAPP to 50 - it is the maximum amount of fertilizer (N) in one application (kg)
6. Change >AUTO_NYR to 300 - it is the maximum amount of fertilizer (N) in one year (kg)
7. Change >AUTO_EFF to 1.3 - it is the fertilization efficiency
8. Change >AFRT_SURFACE to 0.2 - it is the fraction of fertilizer applied in the first layer of soil
   

   ArcView SWAT MGT parameter change
9. Click OK
10. In >LandUses do not do anything! It will apply those settings to all HRUS with this land use.
11. In >Soils do not do anything! It will apply those settings to all HRUS with that soil type.

It should look like something like this:

ArcView SWAT MGT parameter change

1. Click OK to apply it to all the HRU's with that soil and landuse
2. Do not forget to select now other HRU with a different soil type and same crop. Do this steps until all soil types are covered for the first crop type.
3. Do not forget to select now other HRU with a different land use (e.g. AGRC, AGRR, ORCD, RICE...).
4. Run the simulation with SWAT_MOHID as decribed previously in Run_SWAT_Model#Using_SWAT_executable_to_produce_MOHID_outputs

Run SWAT with Point Sources

If running with point sources:

In Menu >Edit Input > Point Sources Discharges

1. see SWAT - Add Point Sources Loads how to add point sources loads.
2. Run the simulation with SWAT_MOHID as decribed previously in Run_SWAT_Model#Using_SWAT_executable_to_produce_MOHID_outputs

SWAT Project with/without point sources

A simulation with point sources (defined flow and concentrations) can be easily transformed in one simulation with no point sources if flow and concentrations are set to zero.

Remind that any change made have to run the simulation with SWAT_MOHID as decribed previously in Run_SWAT_Model#Using_SWAT_executable_to_produce_MOHID_outputs

Run SWAT with Water Quality processes in the river

For now water quality in the river is disconnected

For MapWindow users

File pre-processing

Before running the MWSWAT it is suggested to perform some modifications in the MWSwat database (mwswat.mdb) located in the subfolder ..\Plugins\MWSWAT of the Mapwindow installation directory. In this database, there should be created some Tables that correspond to our modelling site. In our case we would create the following tables, it is important that the keyword in black would be present in the new table created for your site as will serve to the MPSWAT to locate the possible options:

• Divor_weather_sources: Where will be located the site for meteorologicla information.
• pcpDivor:
• Corine2000_landuses:
• crsr_soils:

Create the SWAT Project

1. Run Mapwindow
2. Go to menu "Plug-ins" and select at least the following ones:
   • Watershed Delineation
   • MWSWAT
   • Shapefile Editor
3. When click on the MWSWAT a new window will arise asking if its a new or existing project click on new and browse for a location for this project file.

Step 1 Delineate Watershed

1. After it has been created the project in the main steps will appear a button with the Step 1 that consists in delineate watershed.
   

   MPSWAT initial menu
2. It will open a window that would ask for a Base DEM to be processed. In our case it would be used the digital terrain elevation with the correct projection.
   

   MPSWAT Delineate Watershed
3. Once selected a new open divided vertically in three section appears, in our case we would only modify the "Network delineation by Threshold method, where the units selected would be sq. km. and the cell size of 0.5. In the below section would be chosen the shapefile with the outlet of the watershed that we want to calculate. After that it can be run independently each section or run all in once pressing the button "run all".
   

   MPSWAT Automatic Watershed Delineation menu
4. As a result it will be obtained the main subbasins and the main water courses that lead to the outlet point.
   

   Resulting window from after Step 1 completion

Step 2 Create HRUs

1. If the Step 1 have been completed correctly, the Step 2 button will turn up with the message "Create HRUs".
   

   MPSWAT menu after Step 1 completed
2. Once pressed it would open a new window, where has to be selected our Landuses and soils maps and tables. The Landuse and soil map should have been prepared earlier and the tables loaded in the MWSWAT database. Then press the "Read" button.
   

   Create HRUs menu with the chosen maps and tables
3. Once the grids are read, in our case we would select "Multiple HRUs" from the droping single/multiple HRU menu. It would also be selected the percentage option in the menu HRU threshold by Area/Percentage.
4. Once selected the different percentages for landuse, soil and slope the button "Create HRUs" should be pressed. In this particular example the percentages chosen were 20, 20 and 100 but this will vary for different applications.
   

   Create HRUs menu after choosing the diferent percentages for Multiple HRUs
5. If completed succesfully, a window will provide the information about the HRUs created, in my case they were created 85 HRUs in 60 subbasins.
6. Also at this point, some reports were created about the elevation, basin and HRUs that can be opened from the main MWSWAT window.
7. Diferences of 2-3% between the diferent parts of landuse, soil and slope from the basin report (LanduseSoilSlopeRepSwat.txt) and the HRUs report (HruLanduseSoilSlopeRepSwat.txt) are allowed.

Step 3 Swat Setup and Run

1. If the Step 2 have been totally completed, the Step 3 will be visible and when we click on it a new screen would appear.
   

   MPSWAT menu after Step 2 completed
2. It is suggested that before filling anything in this new menu to click on Weather Sources button. We would choose as the Database tables as a weather source and from the drop down menu the one for our study case (i.e. Divor_Weather_Sources). As the Weather Generator, we would choose the Table option and from the menu the one defined in the MWSWAT database (i.e.wgn_divor). Then clik on Done.
   

   MPSWAT menu for choosing the Weather data sources
3. By doing in this manner, when we come back to the previous menu it can be observed that the Start and Finish date of the period of simulation have been filled with the initial and final data of our database.
4. Then we should click on the write all files box in the right side of the menu and followed by the write files button. If everything run ok another box will appear with the message "SWAT input files written".
5. In this menu you also have the option of running the SWAT model clicking on the Run SWAT button that would open a DOS window where the model will run and if it runs ok a window confirming with the message "SWAT run successful".
   

   MPSWAT menu with the dates corrected, the write files corrected and the message of the SWAT succesful run on top.
6. To edit the SWAT input files click on the "Edit files" button that would open the SWAT Editor 2005 (64 Bit users if you have problems at this point please read carefully the MapWindow Installation Instructions.

Step 4 Run MWSWAT with common calibrations

The commom calibrations are in groundwater, soil, and management files. The first callibration affects flow and the other two affect water quality. Just need to change some parameters in the SWAT Editor, make a new simulation structure and rerun the model in to that structure so that you will have two simulations (the first, default parameters, and the second with parameters more fitted in to our watershed reality).

To modify the SWAT input files, click on edit files on the last menu from MWSWAT and a new window will turn up.

SWAT Editor Main Menu

In the "Edit SWAT Input" menu choose "Subbasin Data". Then in the "Select Input Table To Edit", three modifications will be performed:

1. Soils (.Sol): Select any Subbasin, Land Use, Soils and Slope option and click "ok". A new window will open. In this new window will modify the USLE_K value from 0.1 to 0.3 and will tick the box "Extend edits to all HRUs". Then "Save Edits" and "Exit".
   

   SWAT Editor for Soil parameters
2. Groundwater (.Gw): Select any Subbasin, Land Use, Soils and Slope option and click "ok". A new window will open. In this new window will set the GW_DELAY (days) and ALPHA_BF (days) to 3 and 1 respectively and will tick the box "Extend edits to all HRUs". Then "Save Edits" and "Exit".
   

   SWAT Editor for groundwater parameters
3. Management (.Mgt):Select any Subbasin, Land Use, Soils and Slope option and click "ok". A new window will open. In the top menu choose the "Operations" tab and click on the "Edit Values" and "Edit Operation" buttons. The following values have to be set in the Auto Fertilization operation

AFERT_ID     : 28-10-10
AUTO_NSTRS   : 0.93
AUTO_NAPP    : 50
AUTO_NYR     : 300
AUTO_EFF     : 1.3
AFRT_SURFACE : 0.2

Then tick the boxes "Extend Management Options" and "Extend Edits to Selected HRUs". On the menus select All subbasins, the agricultural Land Uses (use the CTRL button for doing so) and all Soils and Slope and clik on "Save Edits"

SWAT Editor for management parameters

Then we press the "Cancel" button on the Edit Subbasins input menu and we will be back to the SWAT Editor main menu. On the Edit SWAT Input menu there are two important things to do before exiting:

• To update databases after performing any change
• To re-write SWAT input files

Converting SWAT model results to CE-QUAL model input files

In order to do so follow the instructions on the following link .