Upper South Platte River: Slow recovery from sedimentation after the Hayman burn


From The Denver Post (Scott Willoughby):

“How is that poor, mutilated stream doing these days?” [Former Denver Post outdoors editor Bob Saile] queried upon reading the success story of the river through Eleven Mile Canyon last week. “Maybe another follow-up is in order on what is surely going to be a long, long recovery for what used to be the most important section of trout stream in the state.” Like most of the South Platte River, the Deckers section below Cheesman Canyon has seen its share of ups and downs. Along with the upstream reaches of Eleven Mile Canyon profiled on these pages last Wednesday, this downstream segment of the river is on the upswing these days. But a full decade after the fire, it still has a long way to go.

“I thought maybe after 10 years that the sediment would pass, but it’s nowhere near where it needs to be,” said Jeff Spohn, Colorado Parks and Wildlife aquatic biologist for the region. “The lower (Cheesman) canyon is holding up pretty well. But once you get down into that Deckers reach — below Wigwam Creek and Horse Creek — there’s still a lot of sediment coming down. It’s definitely making progress, but if you look at the fish data pre- and post-fire, it’s nowhere close to what it was.”

The most telling statistics relate to brown and rainbow trout size. In 2001, the year before the Hayman Fire, CPW biologists measured the biomass, or pounds of fish per acre, at 216, with 89 fish measuring greater than 14 inches. In 2010, the biomass fell to 88 pounds per acre, 24 fish longer than 14 inches.

The greatest impact is being felt in the lower portion of the 8-mile unit, where the river flattens out. Upstream, from Cheesman Reservoir down to Deckers, the fishery is rebounding, benefiting in part from trophy trout escaping from the privately owned Wigwam Club separating the two reaches.

More South Platte River basin coverage here.

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