Once all of the geometric data are entered, the modeler can then enter any unsteady flow data that are required. To bring up the unsteady flow data editor, select Unsteady Flow Data from the Edit menu on the HEC-RAS main window. The Unsteady flow data editor should appear as shown in Figure 7-1.

Unsteady Flow Data

The user is required to enter boundary conditions at all of the external boundaries of the system, as well as any desired internal locations, and set the initial flow and storage area conditions at the beginning of the simulation.
Boundary conditions are entered by first selecting the Boundary Conditions tab from the Unsteady Flow Data editor. River, Reach, and River Station locations of the external bounds of the system will automatically be entered into the table. Boundary conditions are entered by first selecting a cell in the table for a particular location, then selecting the boundary condition type that is desired at that location. Not all boundary condition types are available for use at all locations. The program will automatically gray-out the boundary condition types that are not relevant when the user highlights a particular location in the table. Users can also add locations for entering internal boundary conditions. To add an additional boundary condition location, select either the Add RS button or the Add Storage Area button. The Add RS button allows users to enter additional river station locations for boundary conditions.

The Add Storage Area button allows user to add storage area locations for insertion of a boundary condition.


Figure 7 1. Unsteady Flow Data Editor