If a draft plan for managing the massive Glen Canyon Dam in northern Arizona gains final approval, the Colorado River could run through the Grand Canyon much as it did before dam-builders arrived there in 1963.
The Glen Canyon draft EIS, released by the Bureau of Reclamation Jan. 6, would protect the canyon from the erratic flows that have characterized the last quarter century.
“Virtually every page of this document represents a new way of thinking about water in the West,” says Tom Jensen, director of the Grand Canyon Trust. “Commissioner Dan Beard and the Bureau of Reclamation have gone far beyond the Bureau’s traditional perspective which viewed Glen Canyon Dam as just a tool to store water and generate power.”
Former Secretary of the Interior Manuel Lujan ordered the EIS in 1989, in response to complaints that changes in water levels of up to 13 feet in one day swept away beaches and artifacts, damaged native plants and fish, and short-changed Indian reservations and other users downstream (HCN, 8/26/91).
In 1991, the Bureau of Reclamation issued interim regulations to manage flows until the EIS was completed. These cut the daily water fluctuations by 75 percent and kept dam discharges between 5,000 and 20,000 cubic feet per second (cfs). Legislators wrote these conservation measures into law in 1992 with the Grand Canyon Protection Act (HCN, 11/2/93). Chief EIS scientist Duncan Patten says that law “now puts the teeth into the draft EIS, and guarantees the measures will be followed.”
The draft EIS lists nine flow alternatives which will be open for public comment through April 11. The Bureau’s preferred alternative, the “Modified Low Fluctuating Flow Alternative,” advocates continuing the same flow levels set by the interim regulations in 1991.
But the new plan also includes important flow exceptions for research and power production, and a new approach which the Bureau calls “adaptive management.” Duncan Patten, senior researcher for the EIS, says “the draft EIS is unique because the flows aren’t set in concrete.” Adaptive management could alter the EIS for endangered fish research, beach habitat restoration and flood protection, he says. This provision makes some environmentalists and power brokers uneasy.
Power distributors worry about the Bureau’s plans to protect the endangered humpback chub and razorback sucker. While biologists say the fish need steady flows through the spring and summer for spawning, representatives from the federal agency that markets hydropower, the Western Area Power Administration, aren’t convinced. WAPA engineer Ron Moulton says the benefits of the steady flows may only be minor. Instead of steady flows, he suggests gradually modifying interim flows to protect the fish.
Almost one-third of the dam’s 1350 megawatt capacity cannot be used under steady flows, says Jerry Demel, a manager for Denver’s Tristate Electric Association. Demel says the limitations would force WAPA to purchase surplus energy from coal-burning plants and other dams during peak energy demand. The switch could cost the average household an additional $180 per year, and would also hurt small businesses and irrigators, he says.
In another conservation measure, the draft EIS suggests allowing 40,000 cfs releases about once every decade to mimic flash floods. Scientists hope the floodwaters would deposit sand and nutrients high above the typical water level, restoring sediments lost to gradual erosion.
The plan would also allow exceptions for power producers. In the preferred alternative, WAPA can still violate dam restrictions about 20 hours per month to respond to sudden demands for power. The 1991 interim guidelines allowed for this exception as well, but WAPA has seldom used it, according to Patten.
Some environmentalists worry that such flexibility might lead to abuse. American Rivers vice president Dale Pontius says his group wants to make sure the final EIS does not allow any changes in dam operations that would compromise the management of the Colorado River as a dynamic natural system.
This article appeared in the print edition of the magazine with the headline Draft plan foresees a freer-flowing Colorado River.
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