HEC-FIA requires a stream centerline for all consequence computations. The life loss computation in HEC-FIA also requires a cross section shapefile, storage area shapefile, and associated HEC-DSS database with stage-hydrograph output at each cross section and storage area for the flood scenarios being assessed.

Stream Centerline, Cross Section, Storage Area

The stream centerline, cross section, and storage area feature classes are stored in the HEC-GeoRAS geodatabase. To create a shapefile of the stream centerline:

  1. Start ArcCatalog. The ArcCatalog window opens.
  2. From the first pane, from the Catalog Tree, browse to the folder that contains the HEC-GeoRAS geodatabase for the HEC-FIA project.
  3. Once the geodatabase file appears in the Contents tab of the main window, double-click on the geodatabase filename (i.e., Truman_SDF.mdb). Now double-click on the geodatabase feature dataset (i.e., RasResults).
  4. The stream centerline file created by HEC-GeoRAS should appear in the list (i.e., River2D). Right-click on the stream centerline filename from the shortcut menu point to Export, click To Shapefile (single).
  5. The Feature Class to Feature Class dialog box opens.
  6. The Input Features box should contain the name of the selected stream centerline file. Browse to location where the shapefile is to be stored by clicking next to the Output Location box. The Output Location browser opens. Browse to the folder where the shapefile is to be stored, click Add. The Output Location browser closes, and the pathname with the selected folder appears in the Output Location box of the Feature Class to Feature Class dialog box.
  7. In the Output Feature Class box, provide a name for the shapefile.
  8. Click OK. The Feature Class to Feature Class dialog box closes and the Feature Class to Feature Class Compute dialog box opens. This dialog box contains information on start time, if creation was successful, end time, and how long it took to create the binary file. Click Close, the Feature Class to Feature Class Compute dialog box closes and the shapefile appears in the selected location.
  9. Now in the selected directory, the shapefile appears. The stream centerline has been successfully exported to a shapefile.
  10. Repeat Steps 1-10 for the storage area (i.e., StorageAreas) shapefile (i.e., Truman_StorageAreas) and the cross sections (i.e., XSCutlines) shapefile (i.e., Truman_XSections).

If HEC-GeoRAS and HEC-RAS were not used to develop the hydraulic results for the study, the stream alignment in HEC-FIA can be imported from an existing line shapefile or digitized using tools in HEC-FIA. Clip the stream centerline to the extents of the study area using the steps described below. Economic consequence can be computed in HEC-FIA using any stream alignment and depth grid as input. However, HEC-FIA cannot compute loss of life consequences unless a cross section shapefile, storage area shapefile, and associated HEC-DSS database are provided as input, which are output from HEC-RAS and HEC-GeoRAS.

HEC-DSS File

For life loss computation, HEC-FIA can obtain flood wave arrival times for individual structures from arrival time grids or from stage-hydrographs stored by HEC-RAS in a HEC-DSS (Hydrologic Engineering Center's Data Storage System) file. The hydraulic engineer needs to configure HEC-RAS to generate stage-hydrographs at all cross section and storage area locations before simulating an event. If the HEC-DSS file already contains hydrograph data for each cross section, skip this section.

  1. Start HEC-RAS. The HEC-RAS window opens.

    Figure: HEC-RAS Main Window

  2. From the toolbar click , the Unsteady Flow Analysis dialog box opens.
  3. From the Options menu, click Stage and Flow Output Locations, the Stage and Flow Output Locations dialog box opens.
  4. From the River list, select (All Rivers).
  5. From the RS box, select (All Rivers).
  6. Click the arrow to select all the cross section locations to the Selected Locations box.

  7. Click OK, the Stage and Flow Output Locations dialog box closes.

    Figure: Unsteady Flow Analysis Dialog Box

  8. From the Unsteady Flow Analysis dialog box, in the DSS Output Filename box, enter the path and the filename of the HEC-DSS file that contains the stage-hydrographs created by HEC-RAS.
  9. Click Compute and the HEC-RAS Computations dialog box opens. When computations are finished, click Close, the HEC-RAS Computations dialog box closes.

  10. The HEC-DSS file is created in the selected location.

    Figure: Stage and Flow Output Locations Dialog Box