WSP00886

• File Number: 8407
• Description: Platte River Basin - River Basin General Publications
• State: CO
• Basin: South Platte
• Water Division: 1
• Date: 4/16/1990
• Author: BOR
• Title: Annual Operating Plans - North Platte Project Water Years 1989-1990
• Water Supply Pro - Doc Type: Report/Study

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DESCRIPTION OF THE COLORADO-BIG THOMPSON PROJECT

The Colorado-Big Thompson Project is one of the largest and most complex
natura 1 resource developments undertaken by the Bureau of Recl amat ion.
It consists of over 100 structures integrated into a transmountain water
diversion system through which multiple benefits are provided to the
people.

The Project spreads over approximately 250 miles in the State of
Colorado. It stores, regulates, and diverts water from the Colorado
River on the western slope of the Rocky Mountains. It provides
supplemental water for irrigation of about 720,000 acres of land,
municipal and industrial use, hydroelectric power, and water-oriented
recreation opportunities.

Major features of the prOject include dams,
powerplants, pumping plants, pipelines, tunnels,
substations, and other associated structures (table

dikes, reservoirs,
transmission lines,
1, exhibits 1 and 2).

The Project diverts approximately 260,000 acre-feet of water annually
(3Iu,OOO acre-feet maximum) from the Colorado River headwaters on the
western slope to the Big Thompson River, a South Platte River tributary
on the eastern slope, for distribution to prOject lands and communities.
The Northern Colorado Water Conservancy District apportions the water
used for irrigation to more than 120 ditches and 60 reservoirs. Eleven
communities receive municipal and industri al water from the Project.
Electric power produced by six powerplants is marketed by the Western
Division of the Pick-Sloan Missouri Basin Program.

The western slope collection system traps runoff from the high mountains
and stores, regulates, and conveys the water to the Alva B. Adams Tunnel
for diversion under the Continental Divide.

To assure irrigation and power generation under prior rights on the
Colorado River, Green Mountain Reservoir was constructed on the Blue
River. Spring runoff is stored in this reservoir and later released to
meet the requirements of the Colorado River, and to allow diversion of
water by the Project throughout the year.

Irrigation systems on the Colorado River, above the Blue River
confluence, were improved to enable continued use of existing rights.
Releases are made from Lake Granby to maintain the Colorado River as a
live fishing stream.

The principal storage features are Lake Granby, Grand Lake, and Shadow
Mountain Reservoir located on the Colorado River near Granby, and Willow
Creek, a tributary below Lake Granby. Willow Creek Pumping Plant lifts
the water 175 feet, which then flows by gravity via the Willow Creek
Feeder Canal to Lake Granby.

Granby Pumping Plant lifts the water 125 feet from Lake Granby to Granby
Pump Canal. The canal conveys the water 1.8 miles to Shadow Mountain
Lake, which also intercepts North Fork flows of the Colorado River.
Shadow Mountain' Lake connects with Grand Lake to make a single body
of water from which diversions flow to the Alva B. Adams Tunnel to begin
the journey to the eastern slope.

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