CDOT working to reduce Straight Creek sediment |

CDOT working to reduce Straight Creek sediment

DILLON – Colorado Department of Transportation (CDOT) workers will spend the next 60 days removing loose rocks and revegetating slopes to keep sediment out of Dillon’s water supply.

The $800,000 project will take place along a 4-mile stretch on the north side of Interstate 70 between the Eisenhower Tunnel and Silverthorne. In addition to removing rocks and planting, workers will remove “scarps,” the eyebrow-like ridges at the tops of slopes, under which nothing can grow.

CDOT crews also will build sediment ponds along the stormwater inlets into Straight Creek. The stream has been adversely affected by the sand CDOT places on the road to provide traction for cars and the sediment that erodes from the steep slopes on the north side of the interstate.

Other work involves replacing some rock-lined filtration structures that have become clogged with sediment and no longer function well, said CDOT project engineer Kevin Brown.

That work will complement work the town of Dillon has done in the past decade to protect its water supply, said public works director Eric Holgerson. The town recently received a $175,000 grant to divert water from the springs near the Eisenhower Tunnel into pipes that flow directly into Straight Creek. Currently, that water flows through culverts along the interstate, picks up sediment and gravel along the way and deposits it in the creek.

CDOT will chip in an additional $100,000 toward those efforts, and Dillon Valley and the town of Dillon will each contribute $5,000.

The Straight Creek Clean-Up Committee and CDOT have worked together since the late 1980s to improve conditions in the stream. But it’s a long way from being complete, Holgerson said.

“Ever since the interstate was built, there has been a lot of sand and erosion that have gotten into Straight Creek,” he said. “I don’t know if it will ever be completely clear of sand. But what’s been done on the upper reaches of Straight Creek has worked. It’s a lot clearer than it’s been before.”

He estimates it will take $15 million to $20 million in capital improvements to restore the stream. But the state only guarantees $100,000 each year for the work.

Holgerson said the state allocates about $40,000 a year to CDOT to clean up the sediment ponds each year, but the state agency needs closer to $430,000, particularly since some of that money is also used to restore Black Gore Creek on the west side of Vail Pass.

That creek, which flows into the Eagle Valley, faces the same problems as Straight Creek.

“There’s not enough money to get it all done,” Holgerson said. “That’s the fight that we have.”

Even incremental work, however, is important.

The work will not only clean up Dillon and Dillon Valley’s source of drinking water, but also will provide a better habitat for fish in the creek – and in the Gold Medal fishing waters downstream in the Blue River.

“We are seeing improvements in the upper reaches where the sediment ponds have been built,” Holgerson said. “Over time, all the sand will be transported out of Straight Creek.”

CDOT plans to seed the slopes with native grasses and flowering plants in the fall. And Holgerson will offer a tour of the stream and the projects on June 24.

Jane Stebbins can be reached at (970) 668-3998 ext. 228 or

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