Split Subbasins Command

The Split Subbasins command of GeoHECHMS software allows the user to split one or more selected subbasins into separate subbasin polygons using a cut polyline. When splitting subbasins, make sure that the cut polyline intersects completely through the selected subbasin polygons.

Follow the steps below to use the Split Subbasins command:

1. From the Watershed ribbon menu, select the Split Subbasins command.
   
2. The Split Subbasins dialog box will be displayed.
   

The following sections describe the Split Subbasins command and how to interact with the above dialog box.

Selecting Subbasins to Split

The Select Subbasins to Split section allows the user to select the subbasins to be split.

The user can click the [Pick] button to select the subbasins from the Map View. After selecting the subbasins, the Pick subbasins read-only field will display the number of selected subbasins.

Alternatively, the user can preselect the subbasins on the Map View prior to running this command. Upon running the command, the number of preselected subbasins will be displayed in the Pick subbasins read-only field.

Defining Cut Polyline

The Define Cut Polyline section allows the user to either draw or select an existing cut polyline from the Map View.

The following options are provided for defining the cut polyline:

Draw Cut Polyline

The Draw cut polyline radio button option allows the user to interactively draw a cut polyline on the Map View.

Follow the steps below to draw a cut polyline on the Map View:

1. Select the Draw cut polyline radio button option and then click the [Draw] button. Alternatively, check the Create curvilinear polyline checkbox to draw the cut polyline using curvilinear segments.
   
2. The Split Subbasins dialog box will temporarily disappear, and a prompt will be displayed on the status bar instructing the user what to do next.
3. Draw the cut polyline on the Map View. While drawing polylines, the user can use the [Ctrl] key to switch between linear and curvilinear digitizing. Refer to this article in our knowledge base to learn more about drawing elements on the Map View.
4. After drawing the cut polyline, right-click and select Done from the displayed context menu.
5. The dialog box will be redisplayed, and the status of the Draw cut polyline read-only field will change from Not Drawn to Drawn.

Pick Cut Polyline

The Pick cut polyline radio button option allows the user to select an existing cut polyline from the Map View.

Follow the steps below to select a cut polyline from the Map View:

1. Select the Pick cut polyline radio button option and then click the [Pick] button.
   
2. The Split Subbasins dialog will temporarily disappear, and a prompt will be displayed on the status bar instructing the user what to do next.
3. Select the cut polyline from the Map View. After selecting the cut polyline, right-click and select Done from the displayed context menu.
4. The dialog box will be redisplayed, and the status of the Pick cut polyline read-only field will change from Not Selected to Selected.

After the cut polyline has been defined, the user can click the [OK] button. The software will split the selected subbasin(s) along the defined cut polyline.