FLOOD10395 ‎(2)‎

• County: Montezuma
• Community: Dolores
• Stream Name: Dolores River
• Title: Dolores River near Dolores, Colorado, Flood Insurance Study
• Date: 5/1/2004
• Prepared For: Dolores
• Prepared By: US Army Corps of Engineers
• Floodplain - Doc Type: Floodplain Report/Masterplan

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The annual flow duration data for Lost Canyon Creek, for rainflood and snowmelt, are

tabulated on Plates 20 and 21, respectively. The peak flow frequency curves and observed peak

flows for Lost Canyon Creek are plotted on Plate 22. Flow frequency curves for longer durations

are not presented because this flood insurance study did not include any storm centerings or

floodplain delineation for Lost Canyon Creek. Based on an analysis ofthe only available

rainflood peak (in 1941) and the annual one-day rainflood data, the Lost Canyon Creek rainflood

peak flow frequency curve from the 1976 hydrology study is still valid. Table 16 provides a

summary of flood magnitudes for the 10%, 2%, 1 %, and 0.2% chance recurrences for the below

Rico, at Dolores, and Lost Canyon Creek gages.

Table 16
Peak Flow Frequency for Dolores River
Flood Magnitudes and Percent Chance Recurrence
(See Plates 12, 14, 16, 18, and 22 for other durations)
Dolores RiveT below Rico
Percent Chance 0.2 1 2 10
Exceedence
Peak Flow (cfs) 4,540 2,590* 2,360* 1,810*
Dolores River at Dolores
Percent Chance 0.2 1 2 10
Exceedence
Peak Flow (cfs) 27,600 11,700 7,860 5,550*
Lost Canyon Creek near Dolores
Percent Chance 0.2 1 2 10
Exceedence
Peak Flow (cfs) 5,340 2,490 1,710 890*
*Snowmelt runoff

8.5 Flow Comparison - HMS Model and Flow Frequency Records. Table 14 lists the

rainflood peak flows at Rico and Dolores for the East Fork and West Fork 1 % storm centerings.

The 1 % rainflood peak flow at Rico gage is 5,260 cfs for the East Fork centering and 2,290 cfs for

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