FLOOD07780

• County: Eagle
• Community: Eagle County
• Basin: Colorado Mainstem
• Title: Hydrology Addendum FIS - Eagle County Unicorporated Areas
• Date: 2/1/2002
• Prepared For: CWCB
• Prepared By: Montgomery Watson Harza
• Floodplain - Doc Type: Floodplain Report/Masterplan

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PREFACE

This Hydrology Addendum (HA) is part of a program by the Colorado Water Conservation Board
(CWCB) to make approximate floodplain maps prepared by the Federal Emergency Management
Agency (FEMA) easier for local governments to use. This CWCB report provides limited
engineering information to support the approximate delineations on the FEMA maps, and it
provides floodplain management information to guide the local governments in the use of the maps.

The official floodplain information for Eagle County Unincorporated Areas is the Rood Insurance
Study (FIS), dated January 25, 1983 (the original is dated May 1980). The FIS was prepared by
FEMA and contains both detailed and approximate floodplain delineations. The approximate
floodplains do not include any engineering information to describe the basis of the approximate
floodplain mapping. The initial purpose of this report, therefore, is to provide the county with
limited supporting information for the approximate floodplain delineations. This HA includes a
description of available hydrologic information for major flooding sources within or adjacent to the
county. In addition, the HA gives the county some basic information about floodplain management
and it provides some alternatives that could be considered in formulating and implementing
floodplain management objectives.

A second function of this report is to assure that the FIS meets the basic technical requirements for
designation and approval by the CWCB. Without the inclusion of basic engineering information,
the approximate floodplain delineations shown on the Eagle County Rood Insurance Rate Maps
(FIRMs) cannot qualify for CWCB designation. Colorado statutes require that local governments
obtain from the CWCB the designation and approval of floodplain information for its use in
regulatory purposes. This HA provides a means for the FIRMs to meet that statutory objective. As
new and more detailed floodplain information becomes available, the approximate floodplain areas
shown on the FIRM panels will become superseded. The CWCB will designate and approve new
information, and rescind old information as appropriate.

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