Set land use threshold exemptions
SECTION 9: I NPUT M ODIFICATION —P OINT S OURCES
Figure 9.3
The Select Point Source dialog pops up (Figure 9.4) if at least one point source of discharge was set in the watershed (see Section 5).
Figure 9.4
All subbasins containing point sources are listed.
2. To edit point source data for a subbasin, select the number of the subbasin from the Select Point Source combo box (Figure 9.5) and click the OK button.
Figure 9.5
3. The Point Discharges Data dialog box will open, displaying the data for the point source in the selected subbasin (Figure 9.6). When the dialog initially appears, the dialog in View mode. This allows the user to view the current parameters for the selected point source. All the controls for editing the data are not enabled (i.e., “grayed out”).
To edit the current parameters for the point source, click the Edit Values button. The dialog is now in Edit mode. The controls for editing the point source become enabled (Figure 9.6). You can now make changes to any of the point source parameters in the dialog. Your edits will not be saved to the SWAT Project Geodatabase until you click the Save Edits button. If
you decide not to save the edits you have made, click the Cancel Edits button, and the parameters for your point source will revert back to their original values.
Figure 9.6
Point source data may be summarized in one of four formats: constant daily loadings, average annual loadings, average monthly loadings, and daily loadings. The Select Point Source Data Type combo box located at the top of the dialog box allows the user to select the data format they prefer.
a. Constant Daily Loadings. By default, this item will be selected. If the point source loadings are to be input as constant daily loadings, verify that the “Constant” item is selected.
This option allows the user to enter the following data: average daily water loading (flow) [m3], sediment loading [tons], organic nitrogen [kg], organic phosphorus [kg], nitrate (NO3) [kg], ammonia (NH3) [kg], nitrite (NO2) [kg], mineral (soluble) phosphorus loading [kg], CBOD loading [kg], dissolved oxygen loading [kg], chlorophyll a loading [kg], soluble pesticide loading [kg], sorbed pesticide [kg], persistent bacteria, less
persistent bacteria (both in [ # bacteria/100 ml]), conservative metal #1 [kg], conservative metal #2, conservative metal #3 [kg], as required by the SWAT model (see the Soil and Water Assessment Tool User's Manual, Version 2009, Chapter 31). This data represents average daily loadings input to the stream network every day of the simulation.
To define the constant daily loadings, enter the data in the section of the dialog box labeled Constant Daily Loadings (Figure 9.7).
Figure 9.7
b. Average annual daily loadings. If the point source loadings are to be input as average daily loadings for each year, verify that the “Annual Records” item is selected from the Select Point Source Data Type combo box.
The Observed Loadings Input Files section in the dialog box is now enabled (Figure 9.8).
Figure 9.8
This option requires the user to summarize daily loadings by year (see the Soil and Water Assessment Tool User's Manual, Version 2009, Chapter 31). Prior to creating the project, a data table should be set up following the format specified for Annual Loadings in Section 3.3.
i. Click the open file folder button to the right of the text box.
ii. A browser will be displayed, allowing the user to select the dBASE file (.dbf) or text file (.txt) containing the point source data from disk (Figure 9.9).
Figure 9.9
iii. Select the file and click Open.
c. Average monthly daily loadings. If the point source loadings are to be input as average daily loadings summarized on a monthly basis, verify that the “Monthly Records” item is selected from the Select Point Source Data Type combo box.
The Observed Loadings Input Files section in the dialog box is now enabled (Figure 9.10).
Figure 9.10
This option requires the user to summarize average daily loadings by month (see the Soil and Water Assessment Tool User's Manual, Version 2009, Chapter 31). Prior to creating the project, a data table
should be set up following the format specified for Monthly Loadings in Section 3.3.
i. Click on the open file folder button to the right of the text box.
ii. A browser will be displayed, allowing the user to select the dBASE file (.dbf) or text file (.txt) containing the point source data from disk (Figure 9.11).
Figure 9.11
iii. Select the file and click Open.
d. Daily Loadings. If the point source loadings are to be input as average daily loadings summarized on a monthly basis, verify that the “Daily Records” item is selected from the Select Point Source Data Type combo box.
The Daily Loadings section of the dialog box is now enabled (Figure 9.12).
Figure 9.12
This option requires the user to summarize loadings by day (see the Soil and Water Assessment Tool User's Manual, Version 2009, Chapter 31). Prior to creating the project, a data table should be set up following the format specified for Daily Loadings in Section 3.3.
i. Click on the open file folder button to the right of the text box.
ii. A browser will be displayed, allowing the user to select the dBASE file (.dbf) or text file (.txt) file containing the point source data from disk (Figure 9.13).
Figure 9.13
iii. Select the file and click Open.
4. When you have finished inputting your point source parameters, click the Save Edits button. This will write the edits to the “pp” table in the SWAT Project Geodatabase. A message box will appear (Figure 9.14).
Figure 9.14
5. Click the Exit button in the Edit Point Discharges Input dialog box to return to the Select Point Source dialog (Figure 9.15).
Figure 9.15
6. Click the Cancel button on the Select Point Source dialog to return the ArcSWAT project, or choose a new point source to edit.