FLOOD03485

• County: Denver
• Community: All
• Stream Name: All
• Basin: South Platte
• Title: Comparison of Estimated Flood Peaks with Historic Floods
• Date: 1/1/1986
• Prepared For: State of Colorado
• Prepared By: USDOI
• Floodplain - Doc Type: Educational/Technical/Reference Information

mated by the USSR to be 2,000 acre-fL This estimate was based on the apparent change in
volume of Lake Mohave as measured by the change in reservoir stage at Davis Dam,

In developing the PMP thunderstorm for comparison with the historic event, the procedures In
HMR 49 [5] were used, This method produced a total rainfall of 11,3 inches in 6 h, The total
rainfall was chronologically distributed according to the prescribed method and resulted in the
most intensive 15- and 30-min rainfall totals of 4,8 and 5.2 in., respectively. This compares
favorably with eyewitness accounts that the most intense rainfall occurred in a 15-min period and
at a rate greater than 3 in per Y, h,

Historic loss rates were computed on the basis of an assumed equivalent uniform depth of rainfall
for the entire basin of 1.9 in [18]. This produced a total storm volume of 2,310 acre-ft in this
22,8-mi' basin, The estimated actual flood volume of 2,000 acre-ft was subtracted, leaving 310
acre.ft of tosses in the 1 Y,-h storm duration. The resulting loss rates were then approximated to
be 0,2 in (initial) and 0,1 in/h (constant). These loss rates are consistent with other PMF studies
done in the desert southwest region for USSR projects and used in the PMF derivation for this
study.

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- Computed PMF hydrograph and histone flood peak for Eldorado Canyon, NV.

PMF PEAK ~ 110700 CF5
PMF 10 HOUR VOLUME ~ 120se AC FT

HISTORIC FLOOD PEAK~ 26000 CFS,
69% OF PMF PEAK

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BUREAU or RECLAMATION
PMF COMPARISON STUDY
PMF LOCRL STORM BRSED ON HMR 49
ELDORRDO CRNYON NEVRDR
LRG ~ 0.75 HR BUCKHORN DUH

HISTORIC FLOOD PEAK ~ 76000 crs ON SEPT 11 1971
KLB 12/20/83

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TIME FROM BEGINNING OF RRINFRLL (hrs)

10

11

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12