ArcSWAT extension of ArcGIS creates an ArcMap project file that contains .. In this tutorial we will concentrate on preparing the rest of the input data for. I wish to apply the SWAT tool in modeling the streamflow of a particular river basin, . watch the tutorial series of ArcSWAT here we made step by step setup of. Hello Friends, After long work on SWAT I have made SWAT tutorial, This covering data preparation to final simulation Step by step guide. This is covering how to.
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The Soil and Water Assessment Tool SWAT is a physically-based continuous-event hydrologic model developed to predict the impact of land management practices on water, sediment, and agricultural chemical yields in large, complex watersheds with varying soils, land use, and management conditions over long periods of time. For simulation, a watershed is subdivided into a number of homogenous subbasins hydrologic response units or HRUs having unique soil, slope and land use properties.
The loading and movement of runoff, sediment, nutrient and pesticide loadings to the main channel in each subbasin is simulated considering the effect of several physical processes that influence the hydrology.
How to Create a Project. Turn on these two extensions. Go to the View menu of ArcMap, hover the mouse over the Toolbar button, a list of tools will appear.
ArcSWAT (Texas A&M University)
These two Geodatabases will be created under the Project Directory. The directory of this Geodatabase is provided by the interface, users should not change this value.
The Watershed Delineation tool will appear. This tool is used to tutorual watershed delineations using a combination of DEM, digitized network, and other user inputs. The detailed procedures on how to use the Watershed Delineation tool are introduced in the following sections: A dialog box with Select option from Select from Map and Load from disk is opened.
Choose Load from disk and select the DEM grid located in your disk and click add. If not, an error dialog will prompt.
After loading DEM hutorial, the button will be activated. Using this button, the user can check the projection information of the DEM Figure 7.
ArcSWAT (Texas A&M University) | UN-SPIDER Knowledge Portal
The DEM properties should correctly define arcswaat grid size and units. The user can change the Z unit to reflect the real situation. These maps are not required but might speed the processing time for the GIS operations.
Click beside Maskthen three options is available to specify the watershed area of interest: Arfswat the Load mask grid from disk option and click OK. Select the mask grid located in your disk, and click ADD. If you have selected the Manually Delineate option, then a toolset will appear and allow you draw polygon mask. These tools provide the capability similar to drawing and editing a polygon theme in ArcMap.
Click on the DRAW button to manually trace the boundary of the watershed area of interest using the mouse. Double click the mouse left button to complete the arrcswat. EDIT Vertex will allow you to adjust the boundary of the mask.
Burning in a stream network. A stream network theme can be superimposed onto the DEM to define the location of the stream network. For the Stream Definition function of the Watershed Delineator, There are two ways to define the watershed and stream network. In this section, the method based threshold area will be introduced. In order to use the threshold method to delineate the watershed and stream network, the Flow Direction and Accumulation needs to be calculated by clicking the button.
Stream definition defines both the wrcswat network and subbasin outlets. Adcswat minimum, maximum, and suggested sub watershed area in hectares is shown in the drainage area box. You have the option of changing the size of the subbasins within the specified range of values. This function plays an important role in determining the detail of the stream network and the size and number of subbasins created. The threshold area defines the drainage area required to form the beginning of a stream.
After setting the threshold value of subbasin, then the ttorial can delineate the stream network and outlets through clicking the button. The drainage network and stream juncture points, used to define subbasin outlets, are displayed on the DEM map grid. Next step is Outlet and Inlet Definition. Before proceeding, you have a number of options: Assuming the outlet and stream definition to be acceptable proceed to inlet definition for the study area.
Inlets represent any point source loading into the study area arcswqt the inlets of drainage into turorial watershed from an upstream area. Main Watershed Outlet s Selection and Definition. In this step the users will select one or more outlet locations to define the boundary of the main watershed. Draw a box covering the desired outlet locations will set the main Watershed Outlets. In this example, select 1 outlet at the downstream edge of the masked area Figure 14 and click the Delineate Watershed button.
Select YES in arxswat following dialog to tutoriap with the delineation of main watershed and subbasins. A prompt box will appear to announce completion of the watershed and subbasin delineation. The delineated watershed with subbasins will be added to the View. If the delineation is not satisfactory or if the user wants to select a different outlet for the watershed, click on the Tutotial Selection button and repeat.
Click on the Calculate Subbasin Parameters button to estimate the subbasin parameters.
This function calculates basic watershed characteristics from the DEM and sub-watershed themes. It also assigns the necessary subbasin identification.
The results of the calculations are stored as additional fields in the streams and subbasins theme database files. Click OK to completion of watershed delineation dialog box. Figure 15 shows the delineated watershed with subbasins. Open the Reach or Watershed attribute tables to view the calculated characteristics.
This feature allows adjacent watershed to be simulated at the same time using SWAT. Do not select an outlet at the upstream of another outlet. At least one outlet must be selected for delineation. The user can add tutoriao remove reservoirs to refine the delineation process.
The procedure is similar to the process of manually adding or removing an outlet. In this exercise, we will not focus on adding or removing a reservoir. However the general procedure is given below for reference.
To add a reservoir, click on the ADD button and with the cross appearing as mouse pointer, click on the subbasin where the reservoir will be added.
The reservoir will be placed at the outlet of the subbasin. A prompt box will be displayed asking for verification of the reservoir placement. If the wrong subbasin is listed, click No and repeat step 7 1. If the correct subbasin is listed, click Yes. Draw a square around the reservoir to be removed by holding the left mouse button and moving the mouse.
A prompt box will be displayed asking for verification of the reservoir removal. If the wrong subbasin is listed, click No and repeat step 7 2. Exit the Watershed Delineation Dialog. Click EXIT in the watershed delineation main dialog. You can view the area and percentage wise distribution of elevation for the entire watershed and each subbasin. Tutkrial completed, you will see the following message: Add DEM Grid 1. Note By specifying the threshold area, we define the stream network for networking.
It means that a minimum number of cells are required to start delineating the stream. The minimum threshold area is for the entire watershed, not for each sub watersheds that are going to be delineated. The suggested area given in this window is the average are that could be used. Main Watershed Outlet s Selection and Definition In this step the users will select one or more outlet locations to ttorial the boundary of the main watershed.
Reservoirs The user can add or remove reservoirs to refine the delineation process.