Crews at Mud Mountain Dam moved more than 450,000 pink salmon and returned them to their natural spawning grounds in the White River.

Since August, crews have worked 24 hours a day, seven days week to haul approximately 750 fish every hour from the Mud Mountain Dam trapping facility near Buckley to a location upstream on the White River.

“I do believe that this is a record number of salmon hauled at any facility in the country in a single season,” said Steve Fransen, a fish biologist with the National Marine Fisheries Service. “Efforts like these serve to substantiate the feasibility of trap-and-haul fish passage alternatives when fish ladders are not feasible.”

Working in conjunction with the Muckleshoot and Puyallup tribes, National Marine Fisheries Service, Washington Department of Fish and Wildlife and U.S. Fish and Wildlife Service, the U.S. Army Corps of Engineerse transports the fish upstream of the dam in specially-equipped tanker trucks and releases them back into the White River.

After the fingerlings hatch, they pass through the tunnels of the dam heading for Puget Sound. Removal of the penstocks and control valves from the intake works and installation of the new radial gates significantly improved their chances of survival.

Pink salmon have always been present in the White River, but the population size was very small.

“The pink salmon didn’t flourish on the White until recently. Improved passage conditions on the White River by increasing instream flow and removal of Tacoma Public Utilities’ pipeline crossing, which may have been a partial barrier, likely contributed to their success, said Jeff Dillon, biologist with the U.S. Army Corps of Engineers. “Once the pink salmon were given free access to the trap, they were able to start colonizing the upper White River watershed and assist their explosive increase in run size.”

Before this year’s run, the record for pink salmon at the trap was more than 127,000 in 2007. Biologists plan to look into causes for the remarkable increase.

The U.S. Army Corps of Engineers operates Mud Mountain Dam on the White River to provide flood risk reduction to the Puyallup River Valley.

For more information on Mud Mountain Dam, visit the Corps of Engineers Web site at www.nws.usace.army.mil and select “Dams and Locks” then “Mud Mountain Dam” from the left column.