FLOOD03186

• County: Statewide
• Community: All
• Stream Name: All
• Basin: Statewide
• Title: Benefit-Cost Analysis of Hazard Mitigation Projects
• Date: 1/1/1996
• Prepared For: FEMA
• Prepared By: FEMA
• Floodplain - Doc Type: Educational/Technical/Reference Information

VERSION 1.0 1/12/95

B-C PROGRAM: Flood Hazard Risk

Flood Profile graphs show the variation of flood elevations with distance
upstream from a waterway confluence, bridge, or street crossing. To
determine the elevations for the building under evaluation, the distance
upstream from a landmark on the Flood Profile graph must be
measured on a map. The Flood Insurance Rate Map (FIRM) may be
used for this purpose. Once the location has been properly identified,
then flood elevations for 10-, 50-, 100-, and 500-year floods are read
from the Flood Profile graph.

An example of a Flood Profile graph from an FIS is shown on the
following page. In this example, stream distance is shown in thousands
of feet above the confluence with Overpeck Creek. The house under
evaluation is located about 7850 feet above the confluence, or 45 feet
upstream from the Vanostrand Avenue overcrossing. Flood elevations
for the 10-, 50-, 100-, and 500-year floods are read from this section of
the Flood Profile graph.

In this example, the 50~year elevation is 128.1 feet; the 100-year
elevation is 127.1 feet; the 50-year elevation is 125.9 feet; the 1o-year
elevation is 124.5 feet; and the channel bottom is 119.5 feet. See the
Flood Profile graph on the next page.

Flood elevations may vary markedly along the stream course
depending on the gradient of the individual stream. Therefore, it is very
Important to read properly the flood elevation data on the Flood Profile
graph for the specific site under evaluation.

For additional guidance on obtaining flood information from Flood
Insurance Studies and Flood Insurance Rate Maps, users are referred
to the following publications:

1. Guide to Fiood Insurance Rate Maps (FIA-14), FEMA,
May, 1988.

2. Flood Proofing, How to Evaluate Your Options"U.S.
Army Corps of Engineers, 1993.

3. Engineering Principles and Practices for Retrofitting
Flood Prone Residential Buildings, FEMA, 1994.

7-3