FLOOD11039

• County: Grand
• Community: Grand County and Incorporated Areas
• Basin: Colorado Mainstem
• Title: FIS - Grand County and Incorporated Areas
• Date: 1/2/2008
• Prepared For: Grand County
• Prepared By: FEMA
• Floodplain - Doc Type: Current FEMA Regulatory Floodplain Information

5.0 INSURANCE APPLICA nON

For flood insurance rating purposes, flood insurance zone designations are assigned to a community
based on the results of the engineering analyses. These zones are as follows:

Zone A

Zone A is the flood insurance rate zone that corresponds to the 100-year floodplains that are
determined in the FIS by approximate methods. Because detailed hydraulic analyses are not
performed for such areas, no BFEs or depths are shown within this zone.

Zone AE

Zone AE is the flood insurance rate zone that corresponds to the lOO-year floodplains that are
determined in the FIS by detailed methods. Whole-foot BFEs derived from the detailed hydraulic
analyses are shown at selected intervals within this zone.

Zone X

Zone X is the flood insurance rate zone that corresponds to areas outside the 500-year floodplain,
areas within the 500-year floodplain, areas of 100-year flooding where average depths are less than
I foot, areas of 100-year flooding where the contributing drainage area is less than I square mile, and
areas protected from the 100-year flood by levees. No BFEs or depths are shown within this zone.

Zone D

Zone D is the flood insurance rate zone that corresponds to unstudied areas where flood hazards are
undetermined, but possible.

6.0 FLOOD INSURANCE RATE MAP

The FIRM is designed for flood insurance and floodplain management applications.

For flood insurance applications, the map designates flood insurance rate zones as described in
Section 5.0 and, in the 100-year floodplains that were studied by detailed methods, shows selected
whole-foot BFEs or average depths. Insurance agents use the zones and BFEs in conjunction with
information on structures and their contents to assign premium rates for flood insurance policies.

For floodplain management applications, the map shows by tints, screens, and symbols the 100- and
500-year floodplains, floodways, and locations of selected cross sections used in the hydraulic
analyses and flood way computations.

The countywide FIRM presents flooding information for the entire geographic area of Grand County.
Previously, FIRMs were prepared for each incorporated community and the unincorporated areas of
the county identified as floodprone. This countywide FIRM also includes flood hazard information
that was presented separately on Flood Boundary and Floodway Maps, where applicable (See
Table 4, "Community Map History").

7.0 OTHER STUDIES

Worrall Engineering published a 1983 Flood Plain Information and Drainage Study (Reference I).
Hydrologic data developed by Worrall Engineering were used in this study. Cross-section data
from the Worrall study were also used for portions of the Fraser River.

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