Morrow Point Dam is a

concrete Concrete is a composite material composed of fine and coarse aggregate bonded together with a fluid cement (cement paste) that hardens (cures) over time. Concrete is the second-most-used substance in the world after water, and is the most wid ...

double-

arch dam An arch dam is a concrete dam that is curved upstream in plan. The arch dam is designed so that the force of the water against it, known as hydrostatic pressure, presses against the arch, causing the arch to straighten slightly and strengthe ...

on the

Gunnison River The Gunnison River is located in western Colorado, United States and is one of the largest tributaries of the Colorado River. Description The river flows east to west and has a drainage area of according to the USGS. The drainage basin of ...

located in

Colorado Colorado (, other variants) is a state in the Mountain West subregion of the Western United States. It encompasses most of the Southern Rocky Mountains, as well as the northeastern portion of the Colorado Plateau and the western edge of the ...

, the first dam of its type built by the U.S.

Bureau of Reclamation The Bureau of Reclamation, and formerly the United States Reclamation Service, is a federal agency under the U.S. Department of the Interior, which oversees water resource management, specifically as it applies to the oversight and opera ...

. Located in the upper Black Canyon of the Gunnison, it creates

Morrow Point Reservoir Morrow Point Reservoir is an artificial reservoir on the Gunnison River in western Colorado. Located in the upper Black Canyon of the Gunnison, the lake was created in 1968 by the U.S. Bureau of Reclamation as part of a larger plan to impound ...

, and is within the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational properti ...

-operated Curecanti National Recreation Area. The dam is between the Blue Mesa Dam (upstream) and the Crystal Dam (downstream). Morrow Point Dam and reservoir are part of the Bureau of Reclamation's Wayne N. Aspinall Unit of the

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. The project provides hydroelectric power, flood control and water storage for participat ...

, which retains the waters of the

Colorado River The Colorado River ( es, Río Colorado) is one of the principal rivers (along with the Rio Grande) in the Southwestern United States and northern Mexico. The river drains an expansive, arid watershed that encompasses parts of seven U.S. s ...

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

hydroelectric Hydroelectricity, or hydroelectric power, is electricity generated from hydropower (water power). Hydropower supplies one sixth of the world's electricity, almost 4500 TWh in 2020, which is more than all other renewable sources combined an ...

power generation.

Description

The dam, powerplant and reservoir are contained in pre-Cambrian metamorphic rocks, primarily micaceous

quartzite Quartzite is a hard, non- foliated metamorphic rock which was originally pure quartz sandstone.Essentials of Geology, 3rd Edition, Stephen Marshak, p 182 Sandstone is converted into quartzite through heating and pressure usually related to tec ...

, quartz-mica,

mica Micas ( ) are a group of silicate minerals whose outstanding physical characteristic is that individual mica crystals can easily be split into extremely thin elastic plates. This characteristic is described as perfect basal cleavage. Mica is ...

and

biotite Biotite is a common group of phyllosilicate minerals within the mica group, with the approximate chemical formula . It is primarily a solid-solution series between the iron- endmember annite, and the magnesium-endmember phlogopite; more ...

schist Schist ( ) is a medium-grained metamorphic rock showing pronounced schistosity. This means that the rock is composed of mineral grains easily seen with a low-power hand lens, oriented in such a way that the rock is easily split into thin flakes ...

s, with granitic veining. The dam site is in a narrow canyon about wide at the river and wide at the top. The spillway discharge falls into a stilling basin whose waters are retained by a weir below the dam. Intake structures near the south abutment feed two diameter penstock tunnels with steel linings leading to the powerplant. A streamflow of is maintained at all times, equivalent to per day.

History

The Curecanti Project (later renamed the Wayne N. Aspinall Project) was conceived in 1955, initially with four dams. It was approved by the Secretary of the Interior in 1959, comprising Blue Mesa Dam and Morrow Point Dam. Crystal Dam's design was unfinished and was approved in 1962. Plans for a fourth dam were dropped as uneconomical. The project was restricted to the stretch of the Gunnison above Black Canyon of the Gunnison National Monument (later designated a national park), a length of the river. Work began at the damsite in 1961 with foundation drilling. In 1962 the power plant exploratory tunnel was excavated. The construction contract for the dam was awarded to a joint venture between the Al Johnson Construction Company and Morrison-Knudsen, with notice to proceed given on June 13, 1963. Access roads and a diversion tunnel were begun that year, with the diversion tunnel complete by May 1964. Keyway excavation on either side of the dam continued through 1964. In 1965 work got underway on the powerplant, with several tunnels started. Concrete for the dam was first placed on September 3, 1965. The powerplant was excavated by April 1966. Final concrete placement on the dam took place on September 14, 1967. The diversion tunnel was closed on January 24, 1968, with releases through the outlet structures the next day. Final completion was achieved for the dam on October 7, 1968, while work continued on the powerplant. The plant was accepted and a visitor center was completed in 1971, with final completion on May 12, 1972. The dam's grout curtain was extended in 1970 after leakage into the power plant reached 429 gallons per minute, using asphaltic emulsion and cement grout, reducing leakage to 37 gpm.

Powerplant

Morrow Point Dam's powerplant is tunneled into the canyon wall below the surface at the dam's left abutment. It houses two 86.667 MW generators, uprated from 60 MW each in 1992-1993. The generating hall measures by , with between and of height. First operating in 1970, it is operated as a peaking plant. An exploratory tunnel became a ventilation tunnel, while initial access during construction was made through the cable tunnel, with two headings raising the head of the tunnel arch. An access tunnel intersects the generating hall at a right angle, with two draft tubes excavated below. In irrigation season the powerplant is operated as a base load plant, providing peaking power in other seasons.

References

External links

Morrow Point Dam
at the Bureau of Reclamation
Morrow Point Powerplant
at the Bureau of Reclamation

at Curecanti National Recreation Area Morrow Point PP Exterior CO2

{{authority control Dams in Colorado Dams on the Gunnison River Arch dams Buildings and structures in Montrose County, Colorado Colorado River Storage Project Curecanti National Recreation Area Hydroelectric power plants in Colorado United States Bureau of Reclamation dams Dams completed in 1968 Energy infrastructure completed in 1968 1968 establishments in Colorado