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.
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.)
"There are two kinds of problems. You might divide them into high water and low water," he begins.
The high-water problems include flooding of beaches (campers wake up in the middle of the night with the water up to the bottoms of their sleeping bags), reduced numbers of beaches available for camping, or equipment and boat losses as the water level surges.
Because the total amount of water flowing through the dam yearly will remain about the same as it has been, higher maximum flows also mean longer periods of low flow. The major danger from this comes from the rapids, which get smaller but more intense.
"This spring we had two accidents directly related to low flow levels," claims mr. Elliot. It is the private boaters who are most at risk because they are not as familiar with the river, he points out. A decade ago only 8 percent of the trips made on the river were made by private parties. Today, private trips have increased to 30 percent and are expected to increase substantially in the future.
Grand Canyon Forest Ranger Marvin jensen, the park's river manager, says that since 1976 the dam has been managed in a way that is less conducive to recreation in the park. WAPA's Wilson, on the other hand, attributes operating differences solely to the 1977 drought and the low-flow conditions that have persisted since then.
In Addition, the increased maximum flow rates threaten "a serious degradation in the quality of wilderness experience and a significant reduction in river use ," says biologist and white-water guide Lawrence E. Stevens. Mr. Stevens is a member of one of four teams that the Bureau of Reclamation has established to investigate the consequences of adding the new turbines.
Along the banks of the Colorado, stretches of vegetation have been established. So far, these have been exotic species such as tamarisk, but gradually native vegetation is taking over, says Stevens. The periodic flow rates that are possible with the proposed modifications to the dam would destroy this vegetation along 31 percent of the river, he estimates.He also argues that during periods of high flow the flooding of beaches in certain stretches of the canyon would lead to several raft trips per day going without adequate campsites.
From the point of view of the recreationists and environmentalists, the best way to operate Glen Canyon would be to moderate variations in water flow.
"I've changed the operation at other dams when there is a reason to. I don't see any benefit in doing this at Glen Canyon," says Wilson. The only people who would benefit, he says, are those who wish to put "Cadillac"-sized boats on the river rather than the "Ford"-sized rafts they are limited to today. "What's so special about the Grand Canyon, anyway?" he asks.
To address these and other concerns, the Bureau of Reclamation has set up a teams of concerned people to make recommendations on the Glen Canyon modifications. "The bureau is patiently and patronizingly answering our questions," river runner Elliot acknowledges.
"We will look for some sort of compromise," assures John Davison, the Bureau of Reclamation's team leader on the Glen Canyon project.