News Release
| Release Number: | 08-039 |
| Dated: | 3/20/2008 |
| Contact: | Amy Echols, 503-808-4510 |
PORTLAND, Ore. — Fish passage at the John Day Dam should get a little easier as the transport and installation of two overflow prototype structures, or weirs, to the dam will begin this weekend, the U.S. Army Corps of Engineers announced today.
These top spillway weirs will support the Corps’ efforts to increase survival for out-migrating juvenile salmon and steelhead in the Columbia River while spilling less water. The weirs, new vertical spillway gates and installation cranes will barge up the Columbia River to the John Day Dam, starting late on March 22. The Corps will install the weirs and gates on March 24 in spillway bays 15 and 16 and begin biological monitoring immediately.
Advanced American Construction Inc. of Portland, Ore., built the weirs and gates at a cost of $1.4 million.
“To help determine the best locations for placing the weirs on the dam’s spillway and the optimal flow patterns to attract fish to the weirs’ entrances, we used research data from two prototype weirs installed at McNary Dam in 2007,” said Bob Wertheimer, Portland District fisheries biologist. “While we made adjustments to weir design for John Day Dam, the application of lessons learned and the information and advances of our salmon recovery efforts up and down the river are saving time and money.”
The weirs are about 25 feet high and 54 feet wide and weigh about 50 tons. The structure can fit into any one of John Day’s spillway bays to create surface spill. The crest of each weir is shaped to create an overflow trajectory that contacts the spillway at a relatively shallow angle.
Juvenile salmon and steelhead using this surface overflow route can pass the dam near the water’s surface under lower accelerations and lower pressures than passing through normal spill. This is anticipated to provide a more efficient and less stressful route while reducing migration delays at the dam.
The U.S. Army Corps of Engineers Portland District provides a variety of services to the citizens of the Pacific Northwest, including safe river navigation, hydropower production and recreation. As part of its environmental stewardship mission, the Corps plays a leadership role in contributing to the sustainability of fish and wildlife species in the Columbia and Willamette river basins that is good for the fish and for people. For more information on fish recovery in the Columbia River Basin, visit www.salmonrecovery.gov.