Basin models are one of the main components of a project. The main purpose of the basin model is to convert atmospheric conditions into streamflow at specific locations in the watershed. Hydrologic elements are used to break the watershed into manageable pieces and are connected in a dendritic network to form a representation of the stream system.
A sink in a basin model is an element with one or more inflows but no outflow. Multiple inflows are added together to determine the total amount of water entering the element. Sinks can be used to represent the lowest point of an interior drainage area or the outlet of the basin model.
In GeoHECHMS, the Sink Data dialog box allows the user to view and edit the sink data.
Follow the steps below to view or modify sink data:
- From the Input ribbon menu, expand the Sinks dropdown menu and select the Sink Data menu item.
- The Sink Data dialog box will be displayed.
The following sections describe how to define the sink data and interact with the above dialog box.
The Select Sink section allows the user to select a sink in order to define the associated sink data.
This section contains the following options:
- Sink ID
This editable dropdown combo box displays the sink(s) defined in the project. The up and down arrow buttons adjacent to the dropdown combo box allow the user to switch between the available sinks. Alternatively, the user can click the […] pick button to select the sink from the Map View. Note that if the project contains only one sink, then the up/down and pick buttons will remain disabled (grayed out).
- Reference flow
This optional entry field allows the user to enter a reference flow value to associate it with the selected sinks. Note that the entered reference flow value does not contribute to and affect the modeling results and the associated parameters.
- Reference label
This optional entry field allows the user to enter a reference label for the selected sink.
This optional entry field allows the user to describe the information about the current sink.
The [New] button allows the user to draw a new sink on the Map View.
The [Copy] button allows the user to create a copy of the current sink on the Map View.
The [Delete] button allows the user to delete the current sink.
The [< Less] and [More >] buttons at the Select Sink header allow the user to hide and display the right side of the dialog box containing the Computed Results plot. This allows the dialog box to be smaller when the user does not want to see the plot view.
This section displays the computational results and the DSS output data associated with the sink.
The Invert elevation optional entry defines the sink invert. The other basin elements such as reach that can connect to the sink do require an invert elevation based upon the specific parameters. Note that the invert elevation of the sink will automatically populate in the Invert elevation entry field if the project contains a terrain elevation source.
This section contains the following sub-sections.
This sub-section displays various flow results of the sink once the analysis of the project is run successfully.
This sub-section displays the information of the output DSS (Digital Storage System) file generated for the HEC-HMS computational results. The DSS file name entry defines the external DSS file to be used for reading the data. The Data path entry defines the data path within the DSS file for the data to be read from.
Computed Results Plot
The Computed Results plot displays the flow hydrograph (i.e., Discharge vs Time plot) of the sink corresponding to the computational results.
Note that if the analysis of the project is not computed, the Computational Results and DSS Data sub-sections will not display any output data, as shown below.