Land & Environment

High Tide for the Colorado River

The first flood was a practice run, as it turned out.

Gates holding back the collected waters of the Colorado River were opened in 1996, and the river, trapped behind the Glen Canyon Dam since 1963, surged free.
The goal was to rebuild sandbars and beaches worn away by the dam’s regulated flow and restore wildlife and fish habitat to a more natural state — in short, to bring a little wildness back to the thoroughly tamed Colorado River ecosystem.
But the roiling, mud-brown floodwaters soon ran crystal clear.
The Nov. 29 issue of the science journal "Nature" highlighted studies conducted by Utah State University geomorphologist Jack Schmidt. His studies determined that there was not enough sediment in the floodwaters to restore beaches and riverbanks. Instead, Schmidt said, the scouring effects of the deluge added to erosion problems. The flood initially built up riverbanks, but the net effect, after the floodwaters had boiled through the channel, was destructive. Some sandbars were partially swept downstream.
The attempt was also a lose-lose situation for hydroelectric companies, who picked up the $2.5 million tab in lost electricity generation.
The project failed.
But not completely, according to "Nature."
"It was a tremendous success as an experiment," Schmidt said. "We learned important things we could not have known had the experiment not been run."
Schmidt and his colleagues carefully gleaned information from the trial run and believe they now have the knowledge to ensure that a second flood will be successful.
Timing, Schmidt discovered, is everything. For hundreds of thousands of years before Glen Canyon Dam was constructed, the river rose and fell in rhythm with the seasons. Its muddy, brown waters were replenished each spring by an icy-clear, ferocious runoff. The scouring torrent swept debris downstream, depositing sediment on sandbars and beaches, creating riverbanks and habitat.
The next flood attempt, Schmidt said, will be timed to coincide with an infusion of fresh sediment from the Colorado’s upstream tributaries, brought by end of summer rains.
Many stakeholders — state governments, Native American tribes, hydroelectric power companies, National Park rangers, conservationists, recreationists, tour guides and archeologists — will be watching the second flood anxiously.
The cold-running river has generated a lot of heat. Power companies and environmental groups have clashing interests, and river restoration efforts may interrupt the smooth flow of hydroelectric power to 15 states.
But according to "Nature," stakeholders all agree the river is in trouble. The historic river has been washed downstream, its beaches in a state of deterioration. The Colorado is now managed to achieve a steady, regulated flow. The unnaturally cold, clear water has given rise to non-native predatory fish populations, while native fish populations have plummeted. Ninety percent of the sediment load settles on the bottom of Lake Powell.
Scientists and planners agree that a second flood is risky because of the long-lasting regional drought, which has lowered the flow and reduced sediment load. But planners are moving forward — cautiously. The carefully negotiated flood plan is part of a compromise agreement. Interested parties would rather thrash out their differences over a negotiating table than in court, and they agree that restoration is long overdue.
Now all parties are waiting for the green light, which is expected to be issued by Secretary of the Interior Gale Norton in the near future.
"We have river guides, power customers and environmentalists looking over our shoulders," said Schmidt. "It’s a pain in the neck and time-consuming. Collecting data is difficult and expensive.
"But it’s one of the most beautiful places on Earth. I would hope people would care about it."
Writer: Nadene Steinhoff, 435-797-1429,
Contact: Jack Schmidt, 435-1791,

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