FLOOD09431

• County: Statewide
• Community: State of Colorado
• Stream Name: All
• Basin: Statewide
• Title: Hydrologic Summary FlS State of Colorado
• Date: 4/1/1981
• Prepared For: FEMA
• Prepared By: Camp Dresser & McKee
• Floodplain - Doc Type: Educational/Technical/Reference Information

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City of Gunnison, Colorado

Streams identified for study in the City of Gunnison are the Gunnison River
and Tomichi Creek (see Appendix B for locations). The review of existing
literature revealed that both streams were studied by Engineering
Consultants Inc., for CWCB, and was presented in the "Floodplain
Information Report, Gunnison River/Tomichi Creek, in Gunnison, Colorado,"
1976 (Reference 2). This report developed frequency-discharge data for
both streams using the methods outlined in Reference 15, and gage data from
USGS stations in the Gunnison River Basin above Blue Mesa Resevoir. The
study was accepted and designated by CWCB for use in floodplain regulation
and management in Gunnison County and the City of Gunnison in 1977.

COM reviewed and supplemented the hydrologic information contained in this
report with additional stream gage data. For both Gunnison River and
Tomichi Creek it was found that our results fell within the 90-percent
confidence limits for all frequencies, excepting the 500-year discharge on
Tomichi Creek (see Figures 4 and 5). This is the result of the two-station
comparison technique as utilized in Reference 2, which was not performed in
COM's analysis. The flow rates presented in the existing Floodplain
Information Report were recommended for use in the flood insurance study
for the community of Gunnison (refer to COM's letter for FEMA and CWCB, May
2, 1980, in Appendix A), and have been summarized in Table 1.

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