Short Takes: Fish Collector

September/October 2009

Safe Passage

Complex new fish collector system captures fish and moves them safely around an Oregon dam

By Debra Wood

Natt McDougall Co. built the Floating Surface Collector superstructure on dry land in March 2007, then installed it on the water and put it into operation behind Upper Baker Dam. (Photo Courtesy of Puget Sound Energy.)

The innovative Upper Baker Dam Floating Surface Collector in Concrete, Wash., attracts and captures young salmon for their safe transport around two dams on the Baker River. “It’s a new method of fish migration,” says Natt McDougall, president, Natt McDougall Co., Tualatin, Ore., and a member of the AGC Oregon-Columbia Chapter. “Several more are on the drawing boards, but this was the first design and installation.”

McDougall completed the $25.2-million project in May 2008 for Puget Sound Energy, Bellevue, Wash., and received a 2009 Aon Build America award for it.

“It’s working and working really well,” says Roger Thompson, PSE spokesman. The utility’s fisheries crews have collected and transported approximately 470,000 young salmon in the 13 months since installation of the collector, moving more than 90% of the watershed’s sea-bound sockeye salmon.

McDougall began the project in February 2007, even as some design work continued. The system includes the floating surface collector, a 130-ft x 60-ft barge with water pumps, fish-holding chambers and control rooms; a 75-ft-high steel net transition structure floating on the surface and attached to the collector assembly; and nylon guide nets, stretching 2,000 ft from one shore to the other and 270 ft deep, reaching to the lake bottom.

(Photo Courtesy of Puget Sound Energy.)

“An exit in the net opens into a large, funnel-shaped transition structure,” says Jerry Johnson, vice president of WorleyParsons Westmar, Bellevue, which engineered the net, transition structures and moorings. “The fish are captured, concentrated into holding chambers, trucked downstream and released.”

The Washington Division of URS in Boise engineered the floating surface collector. McDougall built the main structures onshore, when water levels were 55 ft shallower. When water levels came up in the summer, crews floated the structure’s skeleton and moored it to a causeway to finish the assembly.

The transition structure required building a 400-ft-long, four-rail launch ramp with a 70-ton sled to carry the 130-ton structure into one position, at which time two barge assemblies with eight 50-ton hoists lifted it off the rails and into deeper water, where it was towed into its final position. “It was tricky and scary,” McDougall says. “It’s one of the things I won’t forget.”

Looking through the net transition structure before it was lowered into the water. (Photo Courtesy Natt McDougall Co.)
The FSC corrals young salmon and directs them into containers for transport downstream around two North Cascades dams. (Photo Courtesy Puget Sound Energy(left). & Natt McDougall Co.(right))