That, the U.S. Army Corps of Engineers says, should reduce the number of fish that are killed when traveling through a turbine by up to 4 percent. Survival through the turbines now ranges between 89 percent and 94 percent, depending on flow. With the new turbine, survival rates could improve to between 93 percent and 98 percent. However, the Corps cautions that even though the turbine could be used at other projects to improve juvenile survival, it is not the final answer for downstream migration problems. This is not the silver bullet.
Every project is a little different and fish behave differently at various times of the year.
The 10 turbines at power house number one are 1930's technology, she said, so they need to be replaced anyway. Bonneville's other power house was put into service in 1983 and those turbines do not have to be replaced yet. The conceptual design for the turbine was developed by a regional Turbine Technical Working Group composed of biologists and engineers from the National Marine Fisheries Service, the Corps, the U.S. Dept. of Energy, Bonneville Power Administration, public utility districts, the Idaho National Engineering Laboratory and the Electric Power Research Institute. Chenoweth said the MGR turbine is a specially-designed Kaplan turbine, which is the type it is replacing. In both the old and the new turbines, the blades move to vary pitch.