Geodatabase design for FEMA flood hazard studies

Abstract

As a part of its Map Modernization Program, the Federal Emergency Management Agency (FEMA) has specified how Flood Hazard Mapping Partners will submit geographic information system (GIS) data in the Guidelines and Specifications for Flood Hazard Mapping Partners. Appendix L of the guidelines specifies the Digital Flood Insurance Rate Map (DFIRM) database, which stores information used to create DFIRMs. Appendix N of the same guidelines specifies the Data Capture Standards (DCS) database, which records engineering data and models used to define the flood hazard boundaries. This thesis describes the design of a FEMA Flood Study Geodatabase (FSG), which includes: (1) merging the DFIRM database with the DCS database and removing overlapping tables; (2) converting the relational database into a geodatabase by converting spatial tables, lookup tables, and domain tables to feature classes, object classes, and coded value domains, respectively, and (3) relating the flood hazard data to the National Hydrography Dataset (NHD) through a linear event table. It is also found that a portion of the FSG schema can be correlated to the Arc Hydro data model.