Sources define the elements (i.e., upstream flow sources) where additional inflows can enter the stormwater network model. Typically, this represents an upstream boundary condition such as unmodeled headwater regions for the current model.
In GeoHECHMS, sources can be defined by either drawing or assigning nodes on the Map View using the following commands:
- Draw Sources
- Assign Sources
The Draw/Assign Sources command is used to manually draw/assign multiple source nodes on the Map View, one after another until completed.
Follow the steps below to use the Draw/Assign Sources command:
- From the Input ribbon menu, click the Sources dropdown menu and then choose the Draw/Assign Sources command.
- The following dialog box(s) will be displayed.
- Draw Sources:
- Assign Sources:
- Draw Sources:
The following sections describe how to use the Draw/Assign Sources command and interact with the above dialog box(s).
Drawing Source Nodes
The Draw Source Nodes section is used to draw sources on the Map View using nodes. To draw source nodes, follow the steps below:
- Click the [Draw] button, and the dialog box will temporarily disappear.
- The status bar (shown under the Map View) will prompt you to place a source on the Map View. Click on the Map View to place the source.
- To position the source more accurately, use the mouse roller wheel to zoom into a specific location.
- The Snap Mode option can be enabled to cause the drawn source to snap to the nearest HEC-HMS element.
- Following the placement of a source, the Draw Sources dialog box will be redisplayed, and the Source nodes read-only field will be changed from Not Drawn to Drawn.
Selecting Source Nodes
The Select Source Nodes section is used to select the previously drawn nodes from the Map View to assign them as sources. To assign source nodes, follow the steps below:
- Click the [Pick] button, and the dialog box will temporarily disappear.
- The status bar (shown under the Map View) will prompt you to select a source node from the Map View. Click on the previously drawn source node on the Map View to select it.
- Following the selection of a source node, the Assign Sources dialog box will be redisplayed, and the Source nodes read-only field will be changed from Not Selected to 1 Selected.
The Source Specifications section is used to specify the source ID for each drawn source. The user can assign these IDs either manually or automatically using some predefined formats.
Follow the steps below to assign source IDs to the sources:
- If a source has been drawn while the Source ID radio button option was selected, the user can manually enter the source ID in the corresponding field as shown below.
- Alternatively, the user can enable the Auto-name source ID radio button option to automatically name every newly drawn source as per the user’s predefined naming formats as shown below.
The different naming formats present in the Auto-name source ID option are as follows:
- Source ID prefix: This option allows a prefix to be added to the start of the source ID.
- Source ID digits: This option permits specification of a set number of digits to use for the source ID. For example, using 3 digits causes the source ID to be of the format 001, 002, etc.
- Next available source ID: This entry defines the next element ID number to be used.
- Source ID increment: This entry defines the increment to use when numbering elements. The default value is 1.
- Source ID suffix: This option allows a suffix to be added to the end of the source ID.
- Source ID preview: This entry provides a preview of the source naming specification defined above.
- After providing the Source ID, press the [Enter] key or click on the [Apply] button.
Note that if the auto-name option is enabled and the user returns to the dialog box, the [Apply] button will be disabled because the just drawn sources have already been named and created.
Assigning Invert Elevation
This section allows the user to assign an invert elevation to the source using a terrain model. Define this section before drawing/assigning sources so that the invert elevations can be assigned.
To assign an invert elevation, the Terrain elevation source dropdown combo box supports the following surface types:
- Elevation Grid
- LandXML Data
- TIN Surface
The user can also apply an elevation offset to raise or lower the source by the specified amount by checking the Apply elevation offset checkbox. On selecting this checkbox, the entry field next to it becomes available for entering an elevation offset value. A negative offset value will lower the source by the specified amount.