Digital Flood Insurance Rate Map (DFIRM) Database Overview

FEMA's DFIRM Database is designed to facilitate access to as well as collection, storage, and processing of data developed by FEMA for the NFIP. The DFIRM Database will enable FEMA's mapping partners to share data necessary for hydrologic and hydraulic (H&H) modeling and DFIRM production. In addition, it will enable maps to be rapidly updated and revised in the future. The use of a Geographic Information System (GIS) as a component of the DFIRM Database allows the mapping and engineering data elements to be linked to physical features, georeferenced, and overlaid as needed. This, in turn, allows the database to support a wide variety of existing and visionary FEMA engineering and mapping products, such as automated H&H modeling and mapping; web-based publishing of digital map products; and direct links between base maps, work maps, H&H modeling, and mapping elements.

The DFIRM Database content will vary based on what data are available and/or developed for the study. A subset of the DFIRM Database is the Standard DFIRM Database product, which contains all of the required elements to produce a printed DFIRM. At a minimum, the Standard DFIRM Database items will be populated and a Standard DFIRM Database product will be produced. However, whenever additional DFIRM Database elements are available they will be collected and stored in the Enhanced DFIRM Database structure. A Standard DFIRM Database product will then be extracted from the available DFIRM Database data.

All DFIRMs will contain certain standard features:

Standard DFIRM Database

Screen capture of ArcInfo programFEMA previously released the design of the Standard DFIRM Database - the relational database and GIS mapping data that make up a current official DFIRM. The Standard DFIRM Database contains the necessary GIS spatial data elements used to create the DFIRM paper map so that users may identify Base Flood Elevations (BFEs) and Special Flood Hazard Areas on a community or countywide basis. The Standard DFIRM Database product will be created for all DFIRMs. (Click image to enlarge)

The data contents and requirements of the Standard DFIRM Database are defined in Appendix L of FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners. Appendix L was recently updated to reflect all changes made since February 2002. It now includes all elements of the Standard and Enhanced DFIRM Database in one document. Each table description includes an indicator of whether the table is a Standard, Enhanced, or Standard and Enhanced table. Additionally, within each table definition a column is included that identifies (by using S or E) whether each item is a component of the Standard DFIRM Database or the Enhanced DFIRM Database. In general, Standard DFIRM Database items are at the beginning of each table followed by Enhanced items if applicable.

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Enhanced DFIRM Database

A design of the Enhanced DFIRM Database has been developed and is included in Appendix L of FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners. In addition to all of the elements in the Standard DFIRM Database, the Enhanced version contains pertinent back-up engineering data needed by FEMA mapping partners for flood studies, map revisions, or map maintenance. It includes information needed for core NFIP functions such as Mapping Coordination Contractor (MCC) review, insurance rating, and compliance monitoring. It includes sufficient data to allow users to reproduce the flood profile and water surfaces. Additionally, it stores original products and intermediate products of high value and/or wide applicability. It does not include all intermediate data developed in the course of conducting the flood study. Some of the Enhanced DFIRM Database features may be stored in GIS mapping layers or related tables but not shown on the paper FIRM product.

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Documents

  1. Overview of FEMA's Flood Hazard Spatial Databases
  2. Specifications for the DFIRM Database as detailed in FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L.

Standard DFIRM Database
Enhanced DFIRM Database
DFIRM Home

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Last Modified: Thursday, 10-May-2007 15:19:54 EDT