Concrete dam gone, but Whychus work not over
Feb 03, 2015
Footbridge replacement, channel filling set for this yearBy Dylan J. Darling
The last concrete dam blocking Whychus Creek is gone, but more work remains along the creek upstream of Sisters.
Late last summer, excavators tore apart the Pine Meadow Ranch dam along the creek as it parallels the road to Three Creek Lake. The 6-foot-tall dam was the last of about a half-dozen concrete dams taken out of Whychus Creek and its tributaries over recent years.
The dam removal done, the U.S. Forest Service and partnering conservation groups are now focused on replacing a nearby footbridge over the creek and filling in parts of the creek’s deepest channel.
“There is still a lot of earth-moving that is going to happen,” said Mathias Perle, project manager for the Upper Deschutes Watershed Council. The council, a Bend-based restoration group, and the Deschutes River Conservancy, also based in Bend, are working with the Forest Service on the project.
Total cost of the dam removal, creek restoration and other work connected to the project is about $2 million. The National Fish and Wildlife Foundation, the National Forest Foundation, The Nature Conservancy, Oregon Watershed Enhancement Board, Patagonia, Pelton-Round Butte Mitigation Fund and the Reser Family Foundation all contributed money to pay for the project.
The goal is to create habitat for steelhead and salmon, which have been returning to Whychus Creek since 2009, when Portland General Electric and the Confederated Tribes of Warm Springs finished a submerged fish tower in Lake Billy Chinook. The structure allows fish to migrate from waters flowing to the lake, like Whychus Creek, out to the Pacific Ocean.
Since the late 1800s, a dam of some type has blocked and diverted water from Whychus Creek to Pine Meadow Ranch, about a mile away. Doug Sokol, a member of the family that has long owned the ranch, replaced a log diversion dam at the site with a concrete dam in the late 1980s. Comprised of 120 cubic yards of concrete over a metal frame, the dam stood strong until last September.
Planning the removal took much longer than the removal itself. Devising the plan took about five years of talks, Perle said. Removing the dam took about a week.
The dam sat in a floodplain for Whychus Creek. Along with the dam, berms and dikes — man-made earthen walls — kept the creek mainly in one channel. Part of the planned pending earthwork will include filling in sections of the channel, Perle said, prompting the creek to return to a seasonal pattern of spreading over the floodplain.
Storms in September and December have already brought floods to the stretch of Whychus Creek.
“We had some pretty good flood events that came through,” Perle said.
Project planners wanted to see the flooding, a sign of the creek’s recuperation.
Part of the next step in the revival of this portion of Whychus Creek will be replacing the Whychus Creek Mainline Footbridge . The design of the current bridge creates a narrow passage for the creek, with a pier in the center that may trap passing debris and create a blockage. Originally installed in the 1950s as a bridge for cars, the bridge was decommissioned in the 1980s and converted into a footbridge by the Forest Service, Mike Riehle, supervisory fish biologist for the Sisters Ranger District on the Deschutes National Forest wrote in an email.
Bridge replacement should start the second week in July and take until the end of September, he said. The Forest Service installed a similar bridge a few years ago on Link Creek by Suttle Lake.
Riehle wrote in an email Monday he does not have an exact cost estimate yet, with the planned bridge about to go out for bid.
“The new bridge will be made of steel, will have a slight arch and will have a cedar wooden deck,” he wrote. “The old bridge was made from reused car bridge beams that were treated with creosote.”
While the current footbridge spans about 40 feet, the new steel truss bridge is set to stretch nearly 125 feet, according to plans from the Deschutes National Forest. The new design will also completely clear the creek, removing the pier support for the current bridge.
“So it won’t be as narrow right there for the creek to go through,” Perle said.
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