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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II. DISCUSSION OF HYDROLOGIC REVIEW

The following discussions of the hydrologic analysis have been divided by
community. Generally, the technical review process included an existing
literature search and review, comparison of existing literature to other
hydrologic methods, and coordination with FEMA and state (CWCB) officials.

Town of Buena Vista. Colorado

The streams studied by COM in Buena Vista included Cottonwood Creek and the
Arkansas River (see Vicinity Map, Appendix B). During the existing
literature search, the Flood Hazard Analysis "Cottonwood Creek in the
Vicinity of Buena Vista, Chaffee County, Colorado," prepared by the Soil
Conservation Service, 1978, (Reference 8) was reviewed. The hydrologic
portion of this report contained peak discharge-frequency data for
Cottonwood Creek in Buena Vista. The "Manual for Estimating Flood
Characteri sti cs of Natural Flow Streams in Colorado," TM-l (Reference 1)
was utilized to determine the peak discharges for the 10-, 50-, 100- and
500-year frequency floods. The Flood Hazard Analysis for Cottonwood Creek
was accepted and designated by the Colorado Water Conservation Board
(CWCB), for use in regulating flood prone areas in Buena Vista.

COM performed a statistical gage data analysis as outlined in Reference 15,
for the U.S.G.S. gage on Cottonwood Creek near Buena Vista in order to
check the results in Reference 8. The resulting frequency-discharge curve
is presented in Figure 1. Since the curve on Figure 1 is for the gage
station on Cottonwood Creek (drainage area = 65 sq. mi.), the peak

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