This article was published on: 09/22/20 12:00 AM
For Chinook salmon heading upstream in Whychus Creek in search of prime spawning grounds, the journey is about to become much easier.
Work is underway to remove the Plainview Dam, a barrier that for decades prevented fish from migrating to the farthest reaches of Whychus Creek.
Work to remove the dam started earlier this month and was planned for completion by late October. The recent fires and smoke impacting Oregon temporarily halted the project, but organizers remain hopeful the work to remove the dam can resume this fall, according to Kris Knight, executive director of the Upper Deschutes Watershed Council, which is leading and managing the project.
The Plainview Dam is the sixth and final project to remove or retrofit dams on Whychus Creek. The projects, which date back to 2008, open up 38 miles of spawning and rearing habitat for fish.
“All of those previous projects were important like this project is important, but this one has special meaning because it is the culmination of more than a decade of work by many partners and private landowners,” said Knight.
“There is more work that remains on Whychus Creek to restore habitat for salmon, steelhead and resident fish and more work to do to keep conserving water to put back in Whychus Creek, but removing this last fish passage barrier is a moment worthy of celebrating.”
Hundreds of dams have been removed from U.S. rivers over the past two decades as states pursue habitat restoration policies. Restoration of Whychus Creek will benefit fish, which saw large population declines after the construction of dams in the middle and upper Deschutes.
Modern irrigation technology is helping too, as less water will need to be diverted for farming once canals are converted to pipes.
The project to remove the Plainview Dam, which was erected in the 1950s, is a collaborative effort by multiple entities. The Watershed Council has been joined by the Three Sisters Irrigation District, the Deschutes National Forest, the Natural Resources Conservation Service, and private water rights holders are jointly participating.
Dam removal and river restoration allows steelhead, salmon, and other anadromous fish to migrate farther into the river systems of Central Oregon, where they can find cooler waters that are more suitable for spawning and rearing.
“The goal with these restoration projects is to restore conditions within the watershed that will help re-introduction of anadromous fish be as successful as possible,” said Mathias Perle, restoration program manager for the Upper Deschutes Watershed Council.
“This includes making sure fish can access all available habitat through removal of barriers and it also includes restoring and protecting habitat while also ensuring there is sufficient cold water in the creek,” Perle added.
Chinook and steelhead were re-introduced in Whychus Creek starting in 2007. Since then, biologists have seen a slow increase in the numbers of returning fish from the ocean.
In 2019, 11 Chinook returned to Whychus Creek from the ocean and some made it within a mile of Sisters, said Perle.
In addition to removing the Plainview Dam, the agencies are also installing a fish screen on an irrigation diversion to prevent fish from entering an irrigation canal belonging to the Three Sisters Irrigation District.
Another aspect of the project includes piping over 3,000 feet of unlined canal to improve water conservation in the Whychus Creek basin.
The total cost of the project, including the dam removal, piping the canal, and the fish screen will total around $600,000, said Perle. The Oregon Watershed Enhancement Board and the Pelton Round Butte Fund supplied most of the funding for the project for the dam removal and fish screen. The Natural Resources Conservation Service is funding most of the piping project.
Whychus Creek has its headwaters at the foot of Broken Top Mountain, winds through the town of Sisters, and eventually connects with the Deschutes River. The Plainview Dam is located about 4 miles south of Sisters. The project will help fish at various stages of their life cycle, said Perle.
“While juveniles may need calm, slow-moving water with plenty of cover to grow and escape predators, adults may need clean gravels in swifter moving water to lay their eggs,” said Perle. “Having full access to all 38 miles of Whychus Creek will allow fish to find and access the suitable habitats that meet their specific life stages.”
Brett Hodgson, a fish biologist with the Deschutes District of the Oregon Department of Fish and Wildlife, said the project is an important final step for Whychus Creek but work on dams at the lower parts of the river opened up more areas for fish to maneuver.
Plainview “is not a complete barrier and some fish are able to pass over it at the right flows,” said Hodgson. “It is upstream of most of the habitat that is likely to utilized by salmon and steelhead and there is a natural barrier about a mile upstream. “Thus it is positive that this barrier is being addressed; however, it is not as significant as some of the previous projects implemented downstream.”
Work to improve fish habitats and water conservation on Whychus Creek has been ongoing for nearly two decades. The flow of water on the creek was less than 5 cubic feet per second in the early 2000s. Two out of every three years the creek went dry due to the irrigation diversions, according to the Deschutes River Conservancy.
Piping of the canals and water transfers from the mid-2000s helped Whychus recover its streamflow. By 2010, more than 35 cubic feet of water per second was flowing through the creek. That figure is now over 45 cubic feet per second.
Whychus Creek is just one of several waterways in Central Oregon that have been restored in recent years to help fish migrate up and downstream. Projects in the area include a fish ladder completed last year on the Crooked River.
The Deschutes River has also seen restorations, especially in the lower stretches of the river to help fish get around the massive Pelton Round Butte Hydroelectric Project.
In late 2019 Portland General Electric placed dozens of logs and boulders, plus 1,500 tons of river rock, into the Deschutes near Warm Springs to improve habitats for fish.
Reporter: 541-617-7818, mkohn@bendbulletin.com