WSP10444

• File Number: 8441.400
• Description: Colorado Big Thompson Project - Reports
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 8/1/1986
• Author: Colo. Water Resource
• Title: Summary Report - Preliminary Hydrologic Analysis
• Water Supply Pro - Doc Type: Report/Study

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2 . 1 WATERSHED DESCRIPTIot-r

2.0 HYDROLOGIC CHARACTERISTics

The Upper ,Coloraiio Rive.r watershed, wh.ich is the subject .ofthis
study,' extendS from the Continental Divide at an elevation in
exoess of 10,000 .feetto. the Cameo gage near Palisade at an
elevlition of about 4,800 feet. (see Figure 2.1). The drainage area,
above the CaUleo gage is approximately 8,000squal:"emiles.

The majortributarie$ to the Colorado River in the study area are:
,the Frase-r; williams Fork, Blue, Piney, Eagle, and Roaring Fork
Rivers. Smaller s,treams which also contribute to the Colorado
River inoludeWillow,Troublesome, Muddy, Rook, Divide, Elk, Rifle,
Parachute" Roan, and Plateau Creeks. Pl:"incipal reservoirs located
in the Upper Colorado River Watershed include Shadow Mountain Lake,
Lake GranbY, Willow Creek Reservoir, and Green Mountain Reservoir,
all operated by the U. S. Bureau of Reclamation (USBR) as part .of
the Colorado-Big Thompson proj.ect (CBT) ; Williams Fork and Dillon
Reservoirs owned by the DWBr Homestake Reservoir, jointly owne<;i by
the cities of .Colorado Springs and Aurora; and Ruedi. Rese'rvoir
operated by the 1JS.BR as part of the ,Fryingpan-Arkansa.s Project.

Precipitation varies. dramatically'
higher elevations, precipitation
wherea,s' in Garfield county annual
inches per year. SnOWfall in the
October and ends as late as ,the end

within the Study area.' At the
exceeds 30 inches per year,
precipitation. is as low as 10'
study area begins as early as
of April.

AVerage annu,al virgin flow of thecolorad<;> RiVer (based on 1951~
.1983 'historical flows, adjusted for major diversions and reservoirs
as d;escribed in Section 4.0) rangeS from about 0.5 million af at
the headwaters near Hot Sulphur Springs to 3.3 million af at the
Cameo. gage. A wide variation in total annual' virgin flow is
characteristic of the river as illus,trated by annual extremes' at

2-1 '