Crystal Dam
Encyclopedia
Crystal Dam is a 323 feet (98.5 m) double curvature, concrete thin arch dam
Arch dam
An arch dam is a type of dam that is curved and commonly built with concrete. The arch dam is a structure that is designed to curve upstream so that the force of the water against it, known as hydrostatic pressure, presses against the arch, compressing and strengthening the structure as it pushes...

 located six miles downstream from Morrow Point Dam
Morrow Point Dam
Morrow Point Dam is a concrete double-arch dam on the Gunnison River located in Colorado, the first dam of its type built by the U.S. Bureau of Reclamation. Located in the upper Black Canyon of the Gunnison, it creates Morrow Point Reservoir, and is within the National Park Service-operated...

 on the Gunnison River
Gunnison River
The Gunnison River is a tributary of the Colorado River, long, in the Southwest state of Colorado. It is the fifth largest tributary of the Colorado River, with a mean flow of 4320 ft³/s .-Description:...

 in Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...

, USA. Crystal Dam is the newest of the three dams in Curecanti National Recreation Area
Curecanti National Recreation Area
Curecanti National Recreation Area, in Colorado, is formed by three reservoirs, named for corresponding dams on the Gunnison River. The national recreation area borders Black Canyon of the Gunnison National Park on the west...

; construction on the dam was finished in 1976. The dam impounds Crystal Reservoir
Crystal Reservoir
Crystal Reservoir is an artificial reservoir on the Gunnison River in southwestern Colorado operated by the U.S. Bureau of Reclamation. Located in the upper Black Canyon of the Gunnison, it is impounded by tall Crystal Dam, and is within the National Park Service-operated Curecanti National...

. Crystal Dam and reservoir are part of the Bureau of Reclamation's Wayne N. Aspinall Unit of the Colorado River Storage Project
Colorado River Storage Project
The Colorado River Storage Project is a United States Bureau of Reclamation project designed to oversee the development of the upper Colorado River basin...

, which retains the waters of the Colorado River
Colorado River
The Colorado River , is a river in the Southwestern United States and northwestern Mexico, approximately long, draining a part of the arid regions on the western slope of the Rocky Mountains. The watershed of the Colorado River covers in parts of seven U.S. states and two Mexican states...

 and its tributaries for agricultural and municipal use in the American Southwest. The dam's primary purpose is hydroelectric power generation.

Description

Crystal Dam, like the higher Morrow Point Dam
Morrow Point Dam
Morrow Point Dam is a concrete double-arch dam on the Gunnison River located in Colorado, the first dam of its type built by the U.S. Bureau of Reclamation. Located in the upper Black Canyon of the Gunnison, it creates Morrow Point Reservoir, and is within the National Park Service-operated...

 farther upstream, is a thin-shell arch dam, primarily planned to generate hydroelectric power. Unlike its upstream companions, excess water spills over the top of the dam through a notched-out ungated spillway that can create a 227 feet (69.2 m) waterfall in times of overflow.Under normal conditions the river flows though an 11.5 feet (3.5 m) penstock to the 28 MW turbine. The dam is deep within the Black Canyon of the Gunnison in pre-Cambrian metamorphic rock.

History

Crystal Dam was the last of the three dams in the Aspinall Unit of the Colorado River Storage Project to be completed. Crystal Dam's design and construction lagged behind Morrow Point and Blue Mesa
Blue Mesa Dam
Blue Mesa Dam is a zoned earthfill dam on the Gunnison River in Colorado. It creates Blue Mesa Reservoir, and is within Curecanti National Recreation Area just before the river enters the Black Canyon of the Gunnison. The dam is upstream of the Morrow Point Dam. Blue Mesa Dam and reservoir are...

 dams. Construction started in 1964 on a materials borrow pit, with construction at the damsite beginning in 1965 for an access road and exploratory drilling. Work then stopped for five years. Initially planned as an earthfill dam, the design was changed to a double-curvature thin-shell concrete arch dam. After an initial bidding process in which all bid were rejected as too high, a contract for the diversion tunnel was awarded in 1972, which was holed through the same year. The construction contract for the dam itself was awarded to the J.F. Shea Company in June 1973. Cofferdam work continued into 1974, encountering problems with leakage though the upstream cofferdam. 24 inches (61 cm) wells were drilled below the cofferdam to intercept water. In the meantime the dam foundation was excavated, with first concrete placement in June. Excavation and concrete work for the powerplant started the same year. Concrete work stopped in November, resuming in April 1975. Work was behind schedule; the dam was supposed to be completed by December 1975. Concrete work resumed in April 1976, with final completion of the dam structure on August 30, 1976. Filling operations in the reservoir began on March 14, 1977, permanently blocking the diversion tunnel on April 12. The powerplant was not completed until 1978, victim of a fire in the contractor's warehouse that destroyed many electrical components intended for the plant.

Because of Crystal Dam's then-new design, and as a result of the failure of the contemporary Teton Dam
Teton Dam
The Teton Dam was a federally built earthen dam on the Teton River in southeastern Idaho, set between Fremont and Madison counties, USA, which when filling for the first time suffered a catastrophic failure on June 5, 1976. The collapse of the dam resulted in the deaths of 11 peopleand 13,000 head...

in 1976, Crystal Dam was inspected in 1978 by divers to verify the integrity of the structure.

External links

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