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Habitat resurrection means aquatic love connection

Brown trout swarm to spawn at newly restored section of Williams Fork.
Brown trout like this one descended on newly restored river habitat on the Williams Fork. The habitat work led to an intense flurry of spawning activity last fall that surprised biologists. Photo credit: GEI Consultants.


The hottest new place for hookups on the West Slope? A stretch of the Williams Fork River near its confluence with the Colorado.

That’s where the brown trout are frolicking in newly improved habitat that biologists say set the stage for “massive” spawning levels this fall.

The upgraded stream habitat is the outcome of a river restoration partnership between Denver Water and Colorado Parks and Wildlife, with the support of Grand County Learning By Doing partners.

The project, on a nearly 1-mile stretch of the Williams Fork within the Kemp-Breeze State Wildlife Area, increased habitat diversity for all life stages of trout. The restoration work reshaped the channel, removed sediment, created deeper pools and more variety in rock riffles and point bars. All of it designed to create more opportunities for trout to eat, thrive and reproduce.

The work wrapped up in October and the results are exciting — both for the fish and for the biologists who track them.

"The level of spawning that we observed almost immediately after completion of the reclamation work was extraordinary," said Jon Ewert, area aquatic biologist for Colorado Parks and Wildlife. "We saw large spawning beds, indicating thousands of eggs at every tail of the newly constructed pools.”

“It is clear evidence of how beneficial the restoration work will be into the future along this stretch of the Williams Fork River," Ewert added.

Don Conklin, a consultant for Denver Water on the project, visited the site two weeks after the habitat improvement work was completed and had a similar reaction.

“All these pools were constructed as part of the project, and pretty much every one of them had a massive amount of spawning activity,” said Conklin, of GEI Consultants. “The trout are already taking advantage of the new river environment.”

A newly construction "point bar" (left) and cobble lining the opposite bank in the Williams Fork help direct lower flows to the central channel and can also create depth and pools attractive to fish. Photo credit: Denver Water.


A key indicator for spawning success: the presence of “redds,” which are nests in the gravel bottoms where females leave their eggs. Conklin observed a dozen or more redds in most pools.

Ewert reminded anglers to be alert for the redds — areas where the gravel has been cleared off by fish.

“That’s where the eggs are incubating so we ask anglers to be on the lookout for that," Ewert said. "We recommend keeping your distance to avoid causing disturbance and damage."

The river restoration work at the Kemp-Breeze State Wildlife Area is one of several such projects Denver Water and various partners have tackled over the last seven years. Other river restoration work targeted a second stretch of the Williams Fork just upstream of the reservoir, parts of the Fraser River and South Boulder Creek.

The restoration work is tied to commitments in the landmark Colorado River Cooperative Agreement of 2013 and, in certain cases, through Denver Water’s permit with the U.S. Army Corps of Engineers to address impacts of the Gross Reservoir Expansion.