Wednesday, November 22, 2017

Swan River comes another year closer to freedom with 43,000 cubic yards of dredge rock cleared

#Breckenridge #Colorado
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At the turn of the 20th century, dredge miners turned Summit County's rivers upside down in search of gold.
Now, more than 100 years later, restoration workers are flipping the Swan River right-side up again, allowing surface water to flow freely. They hope to eventually transform the barren rubble field back into a healthy ecosystem and trout fishery.
"If we've done our job right, no one will even know we've been there in the next 20 years," said Jason Lederer, a resource specialist with the Summit County Open Space and Trails Department.
The Swan hasn't flowed freely since the dredges chewed up its banks, kept the gold and spat the rocks back out. All of the sand and silt that kept the water out of the ground washed downstream, so the river has quietly gurgled under the rocks for the century since.
"One way to think of it is like a bathtub full of marbles, and the water is just sort of flowing through those," Lederer said. "Sometimes you see it on the surface and sometimes you don't."
The Open Space and Trail Department has teamed up with Breckenridge and at least a half-dozen other partners to breathe life back into the Swan. Clearing out all of the marbles is the first step.
For the past two years, workers have been collecting and milling hundreds of thousands of cubic yards of the gravel and rocks that have been suffocating the river.
On Wednesday, Nov. 22, crews are set to wrap up another season of work, pulling out more than 43,000 tons of material since July. Over that time, the county netted roughly $122,000 in royalties from the sale of that processed material.
A big load of the rock from last season was used for the Iron Springs bypass project, an ambitious re-routing of Highway 9 between Breckenridge and Frisco that was finished just weeks ago.
"The royalties add a lot of value to the project," Lederer said. "These are really expensive projects, but if we're able to get a revenue source out of our contractor's work out there, that's a real win-win for everybody."
Last summer, the project liberated one of four sections of the Swan, digging out a channel that now meanders across a wide floodplain.
"We look at the geometry of the valley as a whole: how wide it is, how steep it is, how big the floodplain is," Lederer explained. "And looking at these different parameters, we can make an inference into what the channel should look like."
This summer, workers planted thousands of willows along the new banks of the Swan to help anchor the river while it stretches it legs for the first time in years. But it's not stuck in place just yet.
"We've given the stream a lot of flexibility to move across the floodplain," Lederer said. "It's able to move a little bit over time, and that's OK — that's kind of what we want up there."
After a dry start to the season, the area greened up nicely before the first snowfall, a stark contrast to the moonlike surface from just two years ago.
The stretch that's flowing, dubbed Reach A, is one of four sections identified for de-dredging. That phase cost around $2.3 million total, provided by a combination of state and local government grants.
Gravel milling work this summer has taken place upriver on Reach B, and that's set to continue next summer. Workers need to clear at least 195,000 cubic yards of material before restoration can begin.
The final two sections, however, are being actively quarried on private land and could take some time to free up for restoration.
"Everyone in the valley is sort of supportive of this work, but I don't have a good idea of the timing on anything on private property," Lederer said. "But ideally, we'll continue to move upstream as the opportunity allows."