Reservoir unleashes more than water

  • Dead trout along the North Fork of the Poudre

    Miles Blumhardt/The Coloradoan
  Biologists braved a morass of mud and fish carcasses in early October while investigating a section of the Poudre River near Fort Collins, Colo. More than 4,000 fish were killed when an irrigation company drained its reservoir to check water gates at the bottom of the dam.

Mike Cola, a dam-safety engineer for the Colorado Division of Water Resources, says the suction created by the open gates pulled out tons of sediment that had accumulated at the bottom of the reservoir.

"It's like something out of Pompeii," says Dave Nickum, Southern Rockies conservation director for Trout Unlimited. The muddy water smothered a three-mile section of the river where deep river pools had supported a prized trout fishery, says Nickum.

Steve Puttmann, the state Division of Wildlife's senior fisheries biologist, believes the situation could have been prevented. "If I had seen what was happening with the sediment, I would have asked the dam folks to shut their gates," he says.

Duane Aranci, acting manager for the North Poudre Irrigation Company, says, "The whole thing's been blown out of proportion." He predicts the silt will eventually move downstream.

But state officials think it will take years for the mud to dissipate and are discussing ways to speed up the process. Puttmann says they're considering trenching the river with backhoes or flushing it with a series of high-water releases.

Puttmann also warns that sediment is accumulating in thousands of small reservoirs all over the Intermountain West, and that more disasters will occur. "It's not a matter of if, just when."

* Patrick Dowd, HCN intern

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