Flexible Spill Operations in the Columbia River

December 20, 2018

On December 14, 2018, the Columbia River System Operations (previously Federal Columbia River Power System) Action Agencies, the States of Oregon, Washington, and the Nez Perce Tribe entered into a “Flexible Spill Agreement” in the spirit of regional collaboration with the shared goal of meeting three objectives: provide fish benefits, provide federal power system benefits, and provide operational feasibility for the U.S. Army Corps of Engineers at federal dams. The flexible spill agreement includes an approximately three-year spill operation at eight federal dams on the lower Columbia and Snake rivers. It is intended to avoid further litigation until the Action Agencies can complete their EIS.

Spill can be an important tool in promoting safe juvenile passage through dams. However, spill must be carefully crafted to address specific dam features and flow conditions in order reduce the potential harm posed by increased spill. Real-time monitoring will alert regional co-managers to any unintended consequences and necessary adjustments. Long-term monitoring will assist with evaluating the effects of the flexible spill operation on fish passage and survival as well as adult returns.

Once NOAA Fisheries formally receives a new proposed action including the flex spill agreement, we will then evaluate the effects of “the flexible spill” operation on salmon and steelhead through models and other means. We plan to issue a new biological opinion for the Columbia River Power System operations in March 2019, in time for the spring spill season.