Bonneville Dam spills water to benefit juvenile salmon, June 2, 2021. This year, federal water managers will spill hundreds of thousands of gallons of water over spillways instead of through turbines during annual “spring spill” operations at U.S. Army Corps of Engineers’ dams on the lower Snake and Columbia rivers. The operations start April 3 on the lower Snake River and April 10 on the lower Columbia River. These actions are intended to decrease the time it takes juvenile salmon and steelhead to move through the system of dams to the Pacific Ocean as well as provide a non-turbine passage route past the 

“[It] is the time of year when we have juvenile salmon migrating downriver,” said Julie Ammann, Northwestern Division, Reservoir Control Center chief.

“Whatever water we put over the spillway, we are not able to put through the turbine units. So, it does change our hydropower generation amounts. 

We do spill every spring, typically starting April 3rd on the Lower Snake River; April 10th down here on the Lower Columbia River. We’ve been doing this operation for several decades.

The amount of spill that we do and how that water is released through the spillway might change a little bit; we make adjustments as we learn more about what works best for fish.

These projects provide a big benefit to the Pacific Northwest through the hydropower, the navigation, our fish operations.”

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