Glen Canyon Dam - Background

Background

In 1922, six U.S. states signed the Colorado River Compact to officially allocate the flow of the Colorado River and its tributaries. Each half of the Colorado River Basin – the upper basin, comprising Colorado, New Mexico, Utah and Wyoming – and the lower basin, with California and Nevada – was allotted 7,500,000 acre feet (9.3 km3) of water annually, and a treaty between the U.S. and Mexico was signed in 1944 allocating 1,500,000 acre feet (1.9 km3) to the latter country. The third lower basin state, Arizona, did not ratify the Compact until 1944 because it was concerned that California might seek to appropriate a portion of its share before it could be put to use. The total, 16,500,000 acre feet (20.4 km3) annually, was believed to represent the river's flow at the time as measured at Lee's Ferry, Arizona (the official dividing point of the upper and lower basins), 16 miles (26 km) downstream of present-day Glen Canyon Dam, while in fact it turned out to be the result of one of the Southwest's climatic shifts during the past 800 years. The actual annual flow past Lee's Ferry is now believed to be about 13,500,000 acre feet (16.7 km3).

Annual discharge from the Colorado River and its tributaries ranges from 4,000,000 to 22,000,000 acre feet (4.9 to 27 km3), and 10-year averages may fluctuate as much as 1,000,000 acre feet (1.2 km3). In addition, the Colorado carries a heavy silt load that led to difficulties for the irrigation interests in the lower Colorado River Valley that were a primary benefactor of the treaties. The general consensus among inhabitants of the Colorado River basin and government officials was that a high dam had to be built on the Colorado to provide flood control and carry-over water storage for times of drought. Possible locations for this dam were debated for years, and in fact the Bureau of Reclamation's first study for a dam at Glen Canyon was made in 1924, in addition to studies for locations at Black and Boulder Canyons lower on the Colorado, below Grand Canyon. However, these studies found that the lower Colorado sites had stronger foundation rock, might result in less reservoir seepage and were easier to access.

The initial need for a reservoir was realized in 1936 with the completion of Hoover Dam in Black Canyon, marking the first time man held control of the Colorado. However, even with Lake Mead's mammoth storage capacity, it was not able to handle the worst floods or droughts, and was filling with sediment at a rate that would render it useless in a few hundred years. But most importantly, Hoover only controlled the lower portion of the river, and the upper basin, whose rivers flowed wild and free, had no way to ensure it could utilize its water allotment in dry years because of the lack of sufficient storage. Arizona also had qualms over the chosen site of Hoover Dam, because it was located in a relatively inaccessible northwestern corner of the state and was too far to provide water to the Gila River Valley, its major population center. A dam at Glen Canyon, just upstream of Lee's Ferry, would both be located entirely within that state and provide much of the power needed to pump water from the Colorado River to Phoenix and Tucson. Finally, the Glen Canyon dam would provide flow regulation between Lee's Ferry and Lake Mead which would make it more economically feasible for the USBR to go ahead with even more ambitious plans to construct hydroelectric generating facilities in the Grand Canyon as part of the Pacific Southwest Water Plan (see Bridge Canyon Dam).

This lack of water surcharge or insurance for the upper Colorado River basin led to a demand for what would later become the Colorado River Storage Project. The general outline of this project was for a dam on the Colorado River at Glen Canyon, several other dams on the Gunnison and San Juan tributaries of the Colorado, and a pair of dams to be built on the Green River, the Colorado's major upper tributary, at Echo Park and Split Mountain. The two Green River dams would have submerged more than 110 miles (180 km) of canyons in the federally protected Dinosaur National Monument, a move abhorred by environmentalists who did not want to see a repeat of the 1924 O'Shaughnessy Dam controversy, when a dam was built in a scenic valley in Yosemite National Park.

Led by David Brower, the environmentalist organization Sierra Club fought a protracted battle against the Bureau of Reclamation, on the basis that "building the dam would not only destroy a unique wilderness area, but would set a terrible precedent for exploiting resources in America's national parks and monuments". In the mid-1950s, the USBR agreed not to build the two dams – an act widely hailed as a major victory for the American environmentalist movement – but only if they could go ahead without opposition with other proposed dams at Flaming Gorge and Glen Canyon. In fact, Brower and the Sierra Club supported the expansion of the proposed dam at Glen Canyon to replace the storage that would have been provided by the Echo Park dam on the Green River. The only qualm that the environmentalists had about the proposed Glen Canyon Dam was that high elevations of its reservoir would extend into Rainbow Bridge National Monument, and a proposal to build a barrier to keep water out of the monument was fought over and litigated for years until it was permanently shelved in 1973. The Colorado River Storage Project was authorized in April 1956, and groundbreaking of Glen Canyon Dam began in October of the same year. A common misconception is that the environmentalists were given a choice between damming Echo Park and damming Glen Canyon, but the USBR "had always planned to build a dam at Glen Canyon, regardless of the outcome of the Echo Park debate".

In 1963, when construction on the dam was well underway, the Sierra Club published a book on Glen Canyon, The Place No One Knew, lamenting the loss of the scenic gorge before most of the American public had a chance to visit, or indeed know it. Brower had visited Glen Canyon shortly after the decision to build the dam, and "realized once he arrived that this was not a place for a reservoir". This was not strictly true as a handful of hikers and boaters (John Wesley Powell for whom the reservoir is named, leader of the Powell Geographic Expedition of 1869, among them) had explored the canyon pre-dam, and some had even been interviewed by Brower. As said to Brower by writer Wallace Stegner, who had been to the canyon in 1947, "Echo doesn't hold a candle to Glen."