Artificial "Flushing" of the Grand Canyon May Damage Sites

Artificial "Flushing" of the Grand Canyon May Damage Sites

Wednesday, March 5, 2008

Keywords: erosion, sediment, preservation, Basketmaker culture, Puebloans
A plan to flush sediment down the Grand Canyon started yesterday over objections raised by the Grand Canyon National Park Superintendent. The US Interior Secretary has ordered that Glen Canyon Dam release millions of cubic feet of water down the Colorado River through the Grand Canyon. Park officials have ten years of studies, done at a cost of $80 million, that prove such artificial flooding will damage the parks' natural and archaeological resources "almost to the point of no return." The Interior Secretary insists the flushes will restore sandy beaches and side pools for wildlife and campers. The Park Superintendent was given only a day to comment on the plan, and he argued that the reasons given for the flooding are "unsubstantiated" by the studies. Instead, he suspects that this has more to do with profits for hydroelectric power companies during peak demand. This suspicion was confirmed, at least in part, by the U.S. Geological Survey. The effects, however, will certainly include irreparable damage to archaeological sites of the Basketmaker culture and Puebloans.
Above: The Colorado River flows at the bottom of the Grand Canyon. Credit: National Park Service.
Excerpts from the Los Angeles Times:
Plans to "Flush" Grand Canyon Stirs Concerns
By Janet Wilson
The Grand Canyon is about to take a bath, and National Park Service officials who oversee the natural wonder are worried.
Federal flood control managers, led by Interior Secretary Dirk Kempthorne, this week plan to unleash millions of cubic feet of water from behind Glen Canyon Dam to "flush" the huge canyon bottom with a simulated springtime flood.
Bureau of Reclamation and U.S. Geological Survey specialists say the 60-hour "blowout," followed by a series of smaller flows this fall, are needed to scour accumulated sand off the Colorado River bottom, then gradually restore sandy beaches and side pools for endangered species and campers. . .
National park officials said that 10 years of research at a cost of $80 million had shown that the flooding as planned could irreparably harm the national park's ecology and resources.
Grand Canyon National Park Supt. Steve Martin said he was given a day to formulate comments to a cursory environmental assessment of the project. In those comments, he wrote that statements by the Bureau of Reclamation used to justify the flows' timing were "unsubstantiated." Far from restoring crucial sand banks and other areas, the flows could destroy habitat, Martin said.
One flood was not enough, Martin said. . . Holding off follow-up flows for months would leave. . . archaeological treasures at river's edge diminished "almost to the point of no return". . .
Martin suggested the timing of the flows served hydroelectric power producers who need peak production during hot summer months. . . The U.S. Geological Survey acknowledged the floods had been timed in part to maximize power generation during peak demand. . .

To read the rest of the article, visit the Los Angeles Times website:
http://www.latimes.com/news/science/environment/la-na-grand4mar04,0,2189507.story
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Excerpts from the Desert Morning News:
High Flow: Glen Canyon Dam Water Release To Move Sediment Downstream
By Stephen Speckman
Caretakers of the Colorado River below the Glen Canyon Dam keep going back to one word when they talk about the health and well-being of the habitat and abundant resources along its 277-mile path through the Grand Canyon.
Balance.
For the hundreds of archaeological sites on or near the river. For the delicate ecosystem beneath the water's surface. For recreation and habitat along its shore. For generating power at the point where the Colorado slips from beneath the 710-foot dam. For resource conservation below the dam. . .
As recently as last Friday, the scales tipped in favor of final approval for what the BOR is careful to say is a "high-flow" experiment — not a flood — that starts at the dam. For 60 hours beginning this morning, 41,000 cubic feet of water per second will flow from the dam's power plant, or pin stocks, and jet tubes.
The flow is supposed to move sediment built up on the river bottom to rebuild or repair beaches downstream. . .
Janet Balsom is the deputy chief of science and resource management for the Grand Canyon National Park. There's a section of shore where she has overseen excavation of an archaeological site that will probably get washed away. Her approach to archeology along the Colorado is preservation first, then, if necessary, excavation.
The problem, however, is that some sites are becoming exposed due to a lack of sediment, or sand, deposited along the banks of the river as a result of the dam's presence. Throughout history most sites have remained hidden because sand and dirt from beaches and shore get moved, usually by wind, around or over sites, in effect protecting them against humans and the elements. There was balance before the dam. . .
"You can't create archaeology," Balsom said about recouping losses that have come over the past 20 years. Currently there are nine sites being actively excavated, also in danger of being lost along the river.
She and others will be watching closely in the months and years ahead how and where sediment deposits settled and how those settlements will interact with irreplaceable archaeological sites. . .

To read the rest of the article, visit the Desert Morning News website:
http://deseretnews.com/article/1,5143,695258755,00.html

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