Enhanced Digital Flood Insurance Rate Map (DFIRM) Database
This web page is provided to distribute information about the design for the Enhanced DFIRM Database to FEMA's partners, customers, and the general public.
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.
The specifications for the Enhanced DFIRM Database are detailed in FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L. This appendix describes the tables and fields contained in the database. 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.
What's in the Enhanced DFIRM Database?
The amount of data that will be captured digitally and stored in the Enhanced DFIRM Database will vary for each flood study. In general, the production of any digital map will result in a complete Standard DFIRM Database. However, most studies will also have same additional data that will be stored in the Enhanced DFIRM Database. Even studies where existing effective flood hazard analyses are used to produce updated digital maps may include easily accessible elements of the Enhanced DFIRM Database. For new studies where new flood hazard analyses are performed, the core elements of the Enhanced Database described will be populated.
The Enhanced DFIRM Database specifications contain additional defined spatial and non-spatial data items and tables that are not in the Standard version. These include the following:
- Subbasins with links to discharges, storm data, and regression equations;
- Gages, including rain gages, river gages, and coastal gages;
- Nodes with links to node discharge data and zipped hydrologic model(s);
- Profile base lines;
- Overbank flow paths;
- Additional cross section data including links to a frequency (rating) table and the zipped hydraulic model(s);
- Additional coastal transect data including links to the zipped coastal model(s);
- Primary frontal dunes;
- Modeled coastal shorelines;
- An outline of the studied area(s) with links to FEMA case information;
- Photographs, sketches, etc. linked to spatial features;
- Documentation for variable data that may be developed for the flood study (e.g., topographic data, land use, soils, roughness);
- Zipped files containing general information on methodology (e.g., Technical Support Data Notebook); and
- Zipped Flood Insurance Study (FIS) documents (e.g., FIS text, flood profiles, Floodway Data Tables).
Review Comments
The Enhanced DFIRM Database design has been circulated for review to FEMA's customers, partners, and contractors. Prototype Enhanced DFIRM Databases will be developed over the next few months and any Iessons learned from prototyping will be incorporated into the final design.
If you have comments on the Enhanced DFIRM Database design, you can E-mail your comments or provide them by facsimile to (703) 960-9125. If you provide comments via facsimile, please include "DFIRM Database Review" on your cover sheet.
If possible, we would be interested in specific recommendations and/or explanations in your review comments. Additionally, we would be interested in your thoughts on the potential cost implications of implementing the Enhanced DFIRM Database.
Documents
- Specifications for the Enhanced DFIRM Database as detailed in FEMA's Guidelines and Specifications for Flood Hazard Mapping Partners, Appendix L. As noted above, this document now includes all elements of the Standard and Enhanced DFIRM Database in one document with indicators that identify which items are Standard and which are Enhanced.
- Table Relationship Diagram(s) of the Combined Standard and Enhanced DFIRM Database.
- Combined Standard and Enhanced DFIRM Database, submitted and distributed versions (zipped Microsoft Access databases including table definition).
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Last Modified: Thursday, 10-May-2007 16:53:05 EDT