WSP11761

• File Number: 8441.400
• Description: Colorado Big Thompson Project - Reports
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 4/1/1987
• Title: Joint-Use Reservoir and Green Mountain Exchange Projects - Summary Report
• Water Supply Pro - Doc Type: Report/Study

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INTRODUCTION

The evaluation of the Joint-Use Reservoir and Green Mountain Exchange Projects (Study)
was initiated by the Colorado Water Resources and Power Development Authority (Authority) at the
request of the Colorado River Water Conservation District (CRWCD) and the Board of Water
Commissioners for the City and County of Denver (DWB). The projects designated for investigation
evolved from two concepts advanced by the Metropolitan Water Roundtable. Organized by the
Governor of the State of Colorado in 1981, the Roundtable discussed and suggested resolution of
the problems associated with increasing water demands in the Denver Metropolitan area and the
concern over water supplies on the western slope of Colorado. The concepts are:

o

Joint-Use Reservoir: A reservoir which would be capable of providing about

30,000 acre-feet (af) of water per year for east slope and west slope use, and

o Green Mountain Exchange: A water exchange project that would utilize Green

Mountain Reservoir, a Replacement Reservoir, and a pump and pipeline

system to increase the water supply to Roberts Tunnel.

, Both concepts would require new reservoirs to regulate flows in the Upper Colorado River

Basin. The Joint-Use Reservoir would retain snow-melt runoff to provide additional water for use in

western Colorado and would partially relieve Dillon Reservoir of its obligation to release water to

meet downstream water demands. The Green Mountain Exchange Project would replace the

required releases from Green Mountain Reservoir with releases from a new Replacement

Reservoir(s) and permit water stored In Green Mountain Reservoir to be pumped upstream to Dillon

Reservoir. The increase in water 'in Dillon Reservoir resulting from either project could be diverted

to the Denver Metropolitan area through the Roberts Tunnel.

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BACKGROUND

Construction of Green Mountain Reservoir on the Blue River was initiated by the Bureau of
Reclamation (USBR) in 1938 as a component 'of the Colorado-Big Thompson (CBT) Project.
Completed in 1959, the CBT Project collects water from the upper reaches of the Colorado River
Basin and delivers it through the Adams Tunnel to the Northern Colorado Water Conservancy District

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