FLOOD02750

• Document ID: 125
• County: Routt
• Stream Name: Elk River
• Basin: Yampa/White
• Water Division: 6
• Title: Streambank Stabilization Limited Watershed
• Date: 11/1/1999
• Prepared For: CWCB
• Prepared By: ICON Engineering, Inc.
• Watershed Pro - Doc Type: Educational/Technical/Reference Information

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basins governed by flash flooding events due to short periods of intense rainfall, as seen along
the Colorado Front Range.

Table 2.2

Elk River Watershed Drainage Areas

ELK RIVER BANK STABILIZATION -ICON PROJECT NO. 99-041-ELK-415
HYDROLOGY - ELK RIVER WATERSHED

BASIN DA % Total Comments % Watershed
sq.mi in Park Range
Mad Creek 40,1 9 Park Range
Big Creek 40,5 10 Park Range
S, Fork Elk 33.9 8 Park Range
M, Fork Elk 20,8 5 Park Range
N, Fork Elk 40,5 10 Park Range 41
Hinman/Coulton Creeks 23.5 6
Willow Creek 72,8 17
Sand Creek/Cottonwood Gulch 27,3 6
Deep Creek/Long Gulch 55,7 13
Salt Creek 16,7 4
Farnsworth Creek/Dry Gulch Areas 29.4 7
Mise, Areas along Mainstem 23,5 6
Steamboat Lake" 35,7 8
Total Elk River Watershed 424.7 100

'Areas from USGS 30x60 Minute Series
"Area included in Willow Creek Drainage Area

Estimating the percentage of average basin runoff that ongmates in the Park Range was
performed as a part of this study, In 1990, W, P. Stanton presented information relating the
mean logarithm of peak flows from snow to both basin area and mean watershed elevation for
both the Upper San Juan River and St. Vrain Creek basins, Assuming that a regression analysis
for the Elk River basin would result in a similar relationship for peak flows from snow, an
effort was made to determine the percentage of runoff from the Park Range based on both basin
area and mean watershed elevation. .

Mean watershed elevations for both the Elk River watershed and the combined watersheds
having headwaters in the Park Range were estimated from the 30 x 60-minute quadrangle
mapping (USGS), Results indicated that the mean watershed elevations are similar, therefore.
the peak discharges would be proportional to the basin areas, Since the combined watershed
area originating in the Park Range makes up approximately 4 I percent of the total drainage
area for the Elk River basin, it is estimated that approximately 41 percent of the average basin
runoff would also originate in this portion of the watershed, This estimation also assumes a
uniform snowfall distribution over the entire watershed, A copy of the supporting information
is included in Appendix B,

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