WSP06431

• File Number: 8281.950
• Description: Colorado River Studies and Investigations -- Upper Colorado Comprehensive Framework Study
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 6/1/1971
• Title: Upper Colorado Region Comprehensive Framework Study - Appendix V - Water Resources
• Water Supply Pro - Doc Type: Report/Study

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SUMMARY

This report presents the results of comprehensive investigations
of water resources for formulation of framework plans to provide a
broad guide to the best use, or combination of uses, of water resources
to meet foreseeable short- and long-term needs, For flexibility in
analysis and planning, the Upper Colorado River upstream from Lee
Ferry, Arizona, has been divided into three subregions comprising the
natural drainages of the Green River, Upper Main Stem, and San Juan-
Colorado. Summaries of water resource data are also prepared for the
states of Arizona, Colorado, New Mexico, Utah, and Wyoming.

Water supply from precipitation averages about 95 million acre-
feet a year. Annual precipitation varies from less than 6 inches in
desert areas of the southwestern portion of the region to over 50
inches in the high elevation headwate,r areas in Colorado. A broad
range of climatic and resulting streamflow conditions exist. Large
variations in annual discharge occur also, from year to year due to
variations in precipitation, and over periods of years due to long-term
climatic trends. Average annual uischarge of the Colorado River at Lee
Ferry was 12,426,000 acre-feet for the 52-year period 1914-65, with
extremes of 21,894,000 acre-feet in 1917 and 4,396,000 acre-feet in
1934. Average annual virgin flow at Lee Ferry, as unaffected by the
activities of man, is estimated at 14.87 million acre-feet over the
52-year period 1914-65.

Estimated average annual withdrawal and consumptive use of ground
water is less than one percent of surface water use. A close relation
exists in many areas between local ground and surface water resources.

Water is used for irrigation, domestic-municipal-industrial
purposes, livestock watering, hydroelectric and thermal electric power
generation, mineral activity, fish and wildlife facilities, and recre-
ation. Large amounts of water are also exported to adjoining regions
for multiple-purpose uses.

A total of 581 reservoirs with usable storage in excess of 29.7
million acre-feet had been constructed by 1965 to provide storage
regulation for various water uses. Since 1965 over one million acre-
feet of additional storage has been constructed or is under construc-
tion. The largest part of the storage capacity has been constructed
as part of the Colorado River Storage Project primarily to provide
long-term regulatory storage.

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