This appendix is written to explain steps for converting data to input types that are supported by HEC-FIA; it is for users who have not upgraded to the latest version of HEC-RAS 5.0. To see the steps for getting the correct data for input to HEC-FIA from HEC-RAS 5.0, go to Appendix G.

The geographic information system (GIS) pre-processing that is required for an HEC-FIA study can be handled through the use of the ESRI ArcGIS® Desktop software. Information and availability about the ArcGIS® Desktop software is available from ESRI (www.esri.com). The software should include ArcMap®, the ArcGIS® 3D Analyst extension, and the ArcGIS® Spatial Analyst extension. Optionally, users can use other GIS platforms like GRASS (http://grass.osgeo.org/) or QGIS (http://www.qgis.org/en/site/)

There are several GIS pre-processing steps that need to be completed before creating a study in HEC-FIA. Depending on the level of detail in the study, not all of the following need to be utilized:

  1. Preparation of maximum inundation depth grids
  2. Preparation of duration and arrival time grids
  3. Creation of maximum inundation area polygon
  4. Generation of the hazard area boundary
  5. Preparation of a digital terrain model
  6. Preparation of arrival time grid for depths two feet and greater
  7. Preparation of various items developed by HEC-GeoRAS (Hydrologic Engineering Center's ArcGIS extension for processing geospatial data for HEC-RAS)
  8. Preparation of emergency planning zone (formerly defined as impact area in HEC-FIA Version 3.0) polygons
  9. Preparation of double warning time polygon
  10. Agricultural grid preparation

Each of these steps is explained in the following sections.