Glen Canyon Dam is an arched dam that has been constructed on the Colorado River in the northern part of the US State of Arizona, close to the town of Page. This 220m high dam was constructed from 1956 to 1966 by the United States Bureau of Reclamation. The Glen Canyon Dam led to the creation of Lake Powell, which is considered one of the largest artificial reservoirs in the United States. The dam has been named after the Glen Canyon, which is a chain of deep sandstone gorges that have currently been filled by the Lake Powell reservoir.
About the Dam
The Glen Canyon Dam is an arch-gravity dam that is situated about 178m above the Colorado River and has a maximum height of 220m from the foundation. The crest of the dam has a length of 480m and a width of 7.6m. The base of the dam has a maximum thickness of 91m and the crest of the dam is placed at an elevation of 1,132m. It is estimated that the dam contains more than 4,110,000 cubic meters of concrete and 13,100,000kg of reinforcing steel. According to the United States Bureau of Reclamation, the dam was built about 26.6km upstream of Lee’s Ferry due to stronger foundation rocks and easy access to the gravel deposits that were present on the Wahweap Creek. As the dam is situated in a rugged and remote area of the Colorado Plateau, a paved road named US Route 89 was also constructed. On August 11, 1957, a 387m long and 210m high Glen Canyon Bridge was built. The Glen Canyon Bridge is considered one of the world’s highest bridges as well as one of the highest bridges in the United States.
On October 15, 1956, construction of the dam began with the first demolition blast that started the process of clearing two diversion tunnels to divert the flow of the Colorado River. By 1959, water began to flow through these tunnels and led to the beginning of the construction of the actual concrete arch dam. Over the next four years, concrete was poured into the dam at the rate of about 6,100 cubic meters every day. The Glen Canyon Dam helps in the equitable distribution of water between the upper basin states and the lower basin states.The closure of the Glen Canyon Dam led to the creation of Lake Powell at the beginning of 1963. To prevent the complete drying of the Colorado River, a minimum flow of 28 cubic meters per second was allowed through the Glen Canyon Dam. The construction of the Glen Canyon Dam finally ended on September 13, 1963. After the construction of the dam wall was complete, the work on building the power plant and spillways began. On September 4, 1964, the first electricity was generated from the Glen Canyon Dam. The Dam currently generates more than 4 billion kilowatt-hours of hydroelectricity annually and is considered the second-biggest hydroelectric power producer in the Southwestern United States.
It took more than 17 years to fill Lake Powell that finally reached its full level of 1,100m on June 22, 1980. Lake Powell is mainly used as a water storage basin for the upper basin states and with a capacity of 33 cubic kilometers of water, the lake is considered as United States’ second-largest artificial lake. The lake is well known for its scenic beauty and offers many recreational activities thereby attracting numerous tourists to the Glen Canyon National Recreation Area every year.
The Glen Canyon Dam brought a lot of changes in the Colorado River ecosystem that severely affected the native aquatic species in the Colorado River. Three species of fish including the bonytail chub, roundtail chub, and the Colorado squawfish have already become extinct and five more fish species are endangered. This is mainly attributed to the fact that there has been an extreme drop in the water temperature associated with the release of sediment-free water from the dam. The dam has also obstructed the free flow of the Colorado River and also significantly reduced its water quality. In addition to this, several invasive species like zebra mussels, channel catfish, Quagga mussels, black crappie, bluegill sunfish, walleye, smallmouth bass, striped bass, largemouth bass, etc have been introduced into Lake Powell and the Colorado River. Moreover, there has been a serious drop in the water level in the Lake Powell reservoir mainly due to climate change that has also led to widespread droughts throughout the western United States.
In the early 1900s, parts of the city of Yuma in Arizona and California’s Imperial Valley were affected by several large floods that destroyed agricultural areas. Following such natural disasters, discussions arose regarding the need of building dams for preventing further floods. In 1922, the Colorado River Impact was passed by both the lower basin and the upper basin states. The lower basin states included Arizona, Nevada, and California, while the upper basin states included Utah, Colorado, Wyoming, and New Mexico. According to the compact, about 9.3 cubic kilometers of water per year would be allotted to the lower basin states and as per the 1944 Mexican Water Treaty, about 1.9 cubic kilometers of water would be given to Mexico. However, since the measurements were taken in an unusually wet season, the upper basin states in some years face trouble in meeting the requirements leading to disagreements between the US States as well as between the US and Mexico. Therefore, to provide more water to the upper basin states and ensure the smooth and proper delivery of water to the lower basin states, the Colorado River Storage Project was proposed by the United States Bureau of Reclamation. Initially, the Echo Park area was chosen for building the dam, but the proposal had to be given up due to severe protests by the conservationists. On April 11, 1956, the construction of the Glen Canyon Dam was authorized by the Colorado River Storage Project. On September 22, 1966, the Glen Canyon Dam was officially dedicated to the nation.