FLOOD06026

• County: Ouray
• Community: Ouray
• Stream Name: Uncompahgre River
• Basin: Gunnison
• Title: North Ouray Uncompahgre River Redevelopment Project
• Date: 11/1/1993
• Prepared For: Ouray
• Prepared By: William Ruzzo
• Floodplain - Doc Type: Floodplain Report/Masterplan

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The City of Ouray is located in southern Ouray County, in sowh-western Colorado.
Durango. Colorado is approximate(v 73 miles to the south and Grand Junction. Colorado is
approximately 100 miles to the the north. UnincOlporated areas of Ouray County surround
the City.

The Uncomphagre River head.....aters rise on the northern slopes of the Sa Juan Mountains,
west of the Continental Divide. at elevations higher than 13,000 feet. The river then flows
nOl'fhwesterly through Ouray, Montrose and Delta Counties for approximately 70 miles to its
confluence with the Gunnison River near the City of Delta. The Uncompahgre River drains
approximatley 1.100 square miles at its confluence with the Gunnison River.

Scope of Study

The scope of services involved two main tasks, (a) development of a HEC-2 model to
approximate the published floodplain infonnation report (Reference I), and (b) evaluation of
proposed channel improvements on the floodplain and water surface elevations. More
specifically the tasks included:

A. Develop preliminary cross sections from station 624+90 to 712+30 and develop a
HEC-2 model from available infonnation.

B. Adjust model to match the 100-year floodplain infonnation presented in the Floodplain
Infonnation Report (Reference I).

C. Perfonn preliminary hydraulic calculations to size a fishing pond, sediment/debris pond
and a new channel section from approximately station 659+00 to 696+00.

D. Investigate impact of proposed channelization on the 100-year floodplain and water
surface elevations.

E. Prepare a report presenting the results.

Principal flood Problems

The Flood Insurance Study for the City of Ouray (Reference 5) provided the following
description of the previous flood problems.

Floodflows on the Uncompahgre River within the Study area result !inm the rapid melting of
the mountain sno\\pack during May. June, and early July. Snowmelt is occasional(v
augmented by rainfall. The I1InojJ fi'om snow melt typically sustains periods of high flows
and marked daily ji/ctuation.

Flow records are not available for all flooding events: however, newspaper accounts show
that major floods occurred in August 1909. June 1921. Ju(v 1927. Ju(v 1929, July 1965 and