FLOOD06021

• County: Larimer
• Stream Name: Big Thompson
• Basin: South Platte
• Title: Flood History of the Big Thompson River Basin: Flash Floods, Paleofloods, and Dam-Break Floods
• Date: 1/1/1979
• Prepared For: Larimer
• Prepared By: USGS
• Floodplain - Doc Type: Flood Documentation Report

For 50 years, the irrigators in the South
Plaue valley had sought the means of de-
veloping a major supplemental water sup-
ply from the far side of the mountains. The
project that exists today illustrates why it was so difficult
to materialize this dream, and why the local people asked
the Bureau of Reclamation to usejts engineering resources
in their behalf.

Project works-more than 100 individual features-are .
scauered over an area of 80 miles east.west and 65 miles
north.south, excluding transmission lines. Major features
are:

Visitors are 'welcome at Granby
Pumping Plant, Green Mountain and
Estes Powerplants, and project head-
quarters at Flatiron, which are the
auended facilities. At the pumping
plant, free tours are conducted dur-
ing June, July, and August. The map
below facilitates planning of travel
over the project.

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PROJECT
WORKS

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10 .-rvoirs (994,340 acre.feet capacity)
6 powerplants (183,9S0 kilowatts capacity)
35 miles of tunnels
95 miles of canals and conduits
3 majot pumping plants
43 substations
784 miles of transmission lines

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USES FOR
RECREATION

The Colorado-Big Thompson Project is helping to meet the
immense public ~emand for recreational opponunities-
more than 2 million visitors a year see project features. Most
of these are sightseers, hut fishermen and boaters heavily
use Granby, Shadow Mountain, Caner, and Horsewoth reservoirs.
Project reservoirs have a total surface area of 14.400 acres. The
National Park Service, which administers nearby Rocky Mountain
National Park, also administers the Shadow Mountain National
Recreation Area including Lake Granby and Shadow Mountain Lake.

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