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Impact Adjustment Map (Option 3) Back Next
Graphic of a map with an impact adjustment variable pamphlet and examples pamphlet.

If a community uses Option 3 for the impact adjustment for Activities 410, 420, 430, 440 and/or 450, it must prepare an Impact Adjustment Map showing:

  1. The area affected by each element of those activities and
  2. The area of the denominator.

No new studies are required to produce an Impact Adjustment Map. The areas are identified and marked on the map based upon the areas under the jurisdiction of the community's regulatory programs.

Many communities have developed a map that meets the requirements of Option 3 for their own management purposes. Some local officials have found the Impact Adjustment Map they developed for CRS credit helpful as a visual presentation of their floodplain management programs. It identifies where the problems are and where the community is dealing with those problems.

The denominators for each activity are:

410 (Additional Flood Data): aSFHA, the area of the Special Flood Hazard Area (on the community's FIRM);

420 (Open Space Preservation): aRF, the total area of regulated floodplain within the community;

430 (Higher Regulatory Standards): aRF, the total area of regulated floodplain within the community;

440 (Flood Data Maintenance): aRF, the total area of regulated floodplain within the community;

450 (Stormwater Management): aW, the total area of watershed affecting the community.

 

Click on a link below to learn more about the Impact Adjustment Map (Option 3).

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