Source data 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, the Source Data command allows the user to add new source and edit source data in a project.
Follow the steps below to view or modify the source data:
- From the Input ribbon menu, click the Sources dropdown menu and then select the Source Data command. Alternatively, the user can double-click on the source element from the Map View.
- The Source Data dialog box will be displayed.
The following sections describe how to use the Source Data command and interact with the above dialog box.
The Select Source section allows the user to select the source for defining the source data. The user can create a new source, copy existing source data to a new source, and delete a source. In addition, the user can navigate between sources and enter a description detailing the defined source.
The following options are provided in this section:
- Source ID
This dropdown combo box lists all the sources that are defined in the project. The user can select the desired source from the dropdown combo box. Click the pencil icon to edit the source ID. The user can navigate between the previous and next sources using the up and down arrow buttons. Alternatively, the user can click the […] button to select the source from the Map View. Note that the up and down arrow buttons will be disabled (i.e., grayed out) when the model contains only a single source.
This text field allows the user to enter additional information to describe the selected source.
The [New] button allows the user to create a new source. On clicking this button, the dialog box will temporarily disappear. A prompt will be displayed on the status bar instructing the user to draw a new source on the Map View. Once finished, press the [Enter] key, or right-click and select Done from the displayed context menu. While drawing a source, the user can press the [Esc] key to abort the creation of a new source, which returns the dialog box to its previous state.The dialog box will be redisplayed. Next, enter the source name in the Source ID entry field and click the [Accept changes] button. The software checks that the defined ID is unique. If not, a warning dialog box is displayed, and the user is then returned to the Source ID field to change the ID.
The [Copy] button allows the user to copy existing source data to a new source. When this command is executed, the software automatically provides a unique default name for the duplicated source. The cursor is then placed into the Source ID. The user can go with the default name or enter a different valid and unique ID before moving on to add any other data.
The [Delete] button allows the user to delete a selected source and its associated data from the project.
This section allows the user to define the data to be used for the current source.
The following options are provided in this section:
- Invert elevation
This entry field allows the user to define the junction invert elevation. Note that HEC-HMS does not use this value, but other elements that can connect to the junction do require an invert elevation based upon specific parameters. For example, reaches require an invert elevation. In addition, profile plots require an invert elevation.
- Upstream drainage area
This entry field only reports the amount of drainage area that contributes flow to the current source node. It is used in the reports generated by the software but is not used in the computations. Clicking on the […] button allows the user to draw a polygon to measure the drainage area.
- Downstream connection
This entry field allows the user to define the downstream element that the selected source node drains to. Clicking on the […] button allows the user to select the downstream element from the Map View. The following elements can be selected:
- Discharge adjustment ratio
This spin control entry field allows the user to specify an adjustment ratio for calibrating the discharge from the selected source. By default, the software uses a value of 1.00, meaning that there is no adjustment. However, the user can enter a different value ranging from 0 to 1.
- Discharge method
This dropdown combo allows the user to select a method for computing the inflow. The following options are available in the dropdown combo box:
- None: When None is selected for the source, the source will have a discharge of exactly zero into the flow network throughout the simulation.
- Constant Discharge (default): When Constant Discharge method is selected for the source, then the Constant discharge and Constant discharge annual pattern entry fields get enabled in the dialog box.
- Discharge Hydrograph: When Discharge Hydrograph method is selected for the source, then the Discharge hydrograph entry field gets enabled in the dialog box.
- Constant discharge
This field allows the user to define the discharge being routed downstream. The same discharge value is used for all time steps during a simulation.
- Constant discharge annual pattern
This dropdown combo box lists the already defined annual patterns. If no annual pattern is defined, then the same discharge value is used for every time interval in the simulation. When a pattern is specified, the discharge value is multiplied by the percentage found in the annual pattern for each time interval in the simulation. The annual pattern provides a percentage that varies throughout the year. The annual pattern must be defined in the Source Constant Discharge Annual Pattern Data dialog box before it can be used in the source element.Clicking on the […] button will display a Source Constant Discharge Annual Pattern Data dialog box, which allows the user to define a new user-defined annual pattern.
- Discharge hydrograph
This dropdown combo box lists the already defined unit hydrograph. The unit hydrograph should record the discharge to use for each time interval during a simulation. If there is missing data in the record and the basin model options are set to replace missing data, a zero flow rate will be substituted for each missing data value. If the basin model is not set to replace missing data, any missing data will cause the simulation to stop and an error message will be displayed. The unit hydrograph must be defined in the Discharge Hydrograph Data dialog box before it can be used in the source element.Clicking on the […] button will display a Discharge Hydrograph Data dialog box, which allows the user to define a new user-defined unit hydrograph.
This section allows the user to see the analysis results for the current source that were computed by HEC-HMS.
This section includes an external DSS file for referencing the HEC-HMS computational results. It allows the user to easily copy the references and paste them into GeoHECRAS.
- DSS file name: This entry defines the external DSS file to be used for reading the data.
- Data path: This entry denotes the data path within the DSS data file which contains the paired data.