Creek work: Water begins flowing in new channel
Steering Fountain Creek into an fish-friendly permanent channel is the latest advance in the restoration project at the north end of the Gold Hill Mesa development.
Only the project area's easternmost 500 feet remain in the temporary channel that contractor Colorado Structures Inc. cut in last summer so it could start developing the new creekbed in a dry state.
The joint $2.3 million project is funded by the City Stormwater Enter-prise, Gold Hill Mesa and the Colorado Department of Transportation (CDOT).
Filling in the gap between two segments of a broader-channeled city stormwater project six years ago (one near 21st Street, the other near Eighth), the current upgrade starts a few hundred feet east of 21st Street and continues east to the boundary of Gold Hill and the trailer park.
It had previously been announced that the work would continue 100 feet farther east than that, to tie in better with the previous city upgrade, but now “there is uncertainty that this second smaller project will happen given the ending of the Stormwater Enterprise and estimated project costs,” said city stormwater engineer Lisa Ross.
The current project's expected completion date is mid-March. Stormwater Director Ken Sampley had predicted a late-December date to City Council in December, but crews were hindered “mainly by weather-related issues, such as the ground being frozen and unable to plant,” Ross said.
A visit to the site Jan. 22 showed steady progress on the project, with extensive bank work on the south side by the finished creekbed, fencing construction along Highway 24, and the start of the last 500 feet of channel.
The permanent creek displays some features that had been requested by Trout Unlimited last year to make the project more fish-friendly, including a narrower main channel, a meandering low-flow channel and strategically placed rocks resulting in fish-inviting pools.
“We're trying to make it as natural as possible in an urban environment,” said Mark Wilson, an architect with THK, the project landscape consultant. “The cobble bottom replicates a natural stream. The fish have opportunities to hide and go to pocket pools.”
Ray Fournier, head of of Colorado Structures, said his crew had found a couple of trout in the creek before the diversion. “We had sushi that night,” he joked, then added seriously, “We salvaged them. They survived.”
Wilson said he doesn't expect fish to be too prevalent for at least a year, saying that time is needed for the newly built creek channel to start attracting the kinds of insects that fish like.
Other work on Fountain Creek has sloped the banks back evenly and sown them with grass and other plantings for stability. There has been a drive for natural water quality in the project, through the use of several “submerged aquatic pools” using types of rushes, sedges and grasses, Wilson said. These capture runoff from Highway 24, acting as a filter for some of the pollutants before the water gets into the creek, he explained.
Prominent along the north creek banks (and eventually on the south as well) are young willows, amid a yellow bed of insulating straw. Wilson said 23,000 willows in all are being planted. He said most should survive - they are hardy, and deer don't like the plant until it starts to put out leaves.
One major operation that can be seen from the highway is the placement of 20-feet-long steel strips called “sheet piles.” At an angle to the creek channel, they are being driven in with hydraulic pressure five feet into bedrock. The piles will help hold the creek banks in place in a big flood, according to Aaron Smith, engineer for project consultant CH2M HILL. Once driven in, the tops of the piles are barely visible, and they will eventually be covered completely by dirt and vegetation, he said.
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