Will fluctuating water flow ruin Grand Canyon?
Grand Canyon, Ariz.
Once again a controversy that pits recreational and environmental values against energy interests is echoing through the Grand Canyon. As before, the Glen Canyon Dam at the head of the canyon is the focus of the current altercation. The daily variations in water flow coming from the dam are the source of the controversy. Fluctuations of water flow through the dam to meet varying power demands cause dramatic changes in downstream water levels.Skip to next paragraph
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Since Glen Canyon Dam was completed, the nature of river and the ecology of the canyon floor have been radically altered. The warm, silt-laden water has become clear and cold. Annual flooding has been eliminated and, in certain stretches, flourishing plant and animal communities have been established. The stream has been stocked with trout and coho salmon. The dam has allowed year-round river rafting even in dry years such as this one.
But environmentalists, who still refer to Glen Canyon as "the dam which never should have been built," are opposed to proposed and ongoing modifications and expansion that would increase the power of the dam.
The dam's turbines are being "rewound" so they can handle larger power flows, in creasingly capacity to 1,150 from 1,000 megawatts. And the Bureau or Reclamation has proposed adding extra turbines which will further increase Glen Canyon's generating capacity by 250 megawatts.
All this is part of an effort to meet an estimated 1.4 million kilowatt increase in peaking power that will be required in the Colorado, Utah, Arizona, and New Mexico area, says Ken Wilson of the western Area Power Administration (WAPA) that distributes the dam's electricity.
Peaking power, needed only during periods of highest demand, is the most expensive form of electricity. It is usually generated by natural gas-burning turbines and oil-fired power plants. WAPA's customer's get peaking power from Glen Canyon at about one-third to one-half the going rate in the region.
"From purely a power point of view, we would maximize our revenue by operating Glen Canyon entirely for peaking power," Mr. Wilson says.
However, the dam is being run continuously at a low level as well to maintain river flows for recreation and wildlife in the canyon, and to fulfill the terms of the interstate Colorado River Compact.
The rewinding and the additional turbines could increase the range of fluctuations in the river level. This is already a problem for commercial and private boaters and rafters who "run" the Grand Canyon.
To a large extent, the Grand Canyon boating industry has grown up with the daily, 10-fold variations in water flows from Glen Canyon. In the last few years, however, they say the variations have gotten larger and more unpredictable.Not only is this creating safety problems, but it also accelerates the rate of deterioration of the canyon's 400 beaches. And they fear that the 22 percent increase in maximum flows possible after the rewindling operation and a further 21 percent increase should the new turbines be added will not only increase these problems but also disrupt the canyon's present environment.
Rob Elliot of Arizona Raft Adventures is a second generation Colorado River runner. He explains the problems which these changes represent for his $12 million per year industry. (About 16,000 people run the canyon each year.)