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

A C value of 0,5 was assumed for this steep desert canyon basin, This value combined with
values of length and stream slope measured on USGS topographic maps resulted In a computed
lag time of 0,75 h, Loss rates were assumed to be 0.2 in (initial) and 0,1 in/h (constant), The
Buckhorn DUH was selected for this basin,

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With the data and assumptions described, a PMF hydrograph with a peak of 98.700 ft3/s was
computed. The measured peak of 73,500 ft3/S represents 74 percent of the PMF peak. Plate 3
shows a comparison of the computed PMF hydrograph peak with the historic flood peak for this
basin,

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Plate 3

Pr"'1 PEAr' ~ SB?etl CfS

PMF Ie HCUR VG~~ME ~ 11400 AC F~

. I,HlSIORICF_LOOD PEAK~ 735()()c:lli
74'Yo OF PMF PEAK

BURERU or RECLAMAT I or~
PMF COMPRRISON STUDY
PMF LOCAL SlORM BRSED ON HMR 49
LAG ~ 0.75 HR BUCKHORN DUH
BRONCO CREEK tlERR HICK:EUP RRIZONR

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HISTORIC FLOOD PEAK - 73500 CfS AUGUST 18 I97l
KLB 1....9/81

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T=~E F~C:~ BEG:~JNING OF RAINFRL.L (hr~)

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- Computed PMF hydrogr3ph and historic flood peak for Bronco Creek near Wickieup, AZ.

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3. Jimmy Camp Creek near Fountain, Colorado

The extreme June 1965 floods on several streams in the Arkansas River Basin in eastern Colorado
and New MeXICO, in many cases. exceeded the potential for flood peaks thought possible based
Oil er,ve!ope curves of the top flood peak discharges experienced in the United States before
1965, 7he most ou;standirg flood event in this area occurred on Jimmy Camp Creek near Fountain,
C~jGr,"iJcNnere d fiood peak estimated at 124,000 ft'/s occurred on June 17, 1965

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