LOWELL, Ore. — Winter time is when reservoir levels are dropped to accommodate spring runoff. But at Fall Creek Reservoir, the U.S. Army Corps of Engineers is trying something new.
Fall Creek Reservoir is one of 13 dams the U.S. Army Corps of Engineers regulates in the Willamette Valley.
Greg Taylor, a USACE fisheries biologist, took us across to get us a better view of how low the water level is.
“In February, we start to refill, so we’ll be letting out less water than what’s coming,” Taylor said.
Taylor says it’s a balancing act. Winter and spring engineers make sure there’s enough room to accommodate runoff. In summer, they regulate and augment flow to maintain water quality. They also monitor the ecosystem and the fish.
When the dam was built back in the ’60s, engineers installed the fish horns for fish to pass through, but they never worked as planned. It had a high mortality associated with it. Two years ago, the Army Corps of Engineers tried a different approach, taking the water down to historic lows.
National Marine Fisheries Service and Sanctuary Video Production & Design produced a time lapse video of the full draw down (click above to watch). For about three days in December water flowed much like it did before the dam, in the actual stream bed.
Taylor is in charge of monitoring fish that pass through the gate. His team check on 600 tagged juvenile salmon. All 600 passed through the gate. The fish that passed through at normal winter levels, the survival rate came in at 80 percent.
When the water was at its lowest, it increased to 97.5 percent, almost a 20-percent improvement.
Some residents voiced concern about what the reservoir looked like. Another issue, sediment deposited down stream. Taylor says the sediment levels are lower this year than last year. He expects if the winter draw down continues, the water quality continue to improve. Most importantly, this alternative approach is helping the fish survive.
“This is an alternative that we’ve come up with that is something we can do. It’s not costly, and it’s working well for the fish,” Taylor said.