The UCSRB Board of Directors approved the third in a series of “All-H” Integrated Recovery summaries at their February 28th meeting. The Hydropower Background Summary located at
This report follows the release of the Habitat Summary in 2014 and the Hatchery Summary in 2017. The background summary documents are intended to support “All-H” collaboration and can be used: a) to improve integrated decision-making; b) as a communication and outreach tool; c) to identify key uncertainties and gaps in knowledge and understanding; and d) to better track and understand progress toward integrated recovery. These documents are based on scientific information and data compiled from a variety of entities working within each sector. This summary is intended to gather information about current dams and dam operations in the mainstem Columbia River in the U.S., their potential risks and benefits, and to summarize what actions have occurred that directly address risk factors or recovery actions identified in the Upper Columbia Spring Chinook Salmon and Steelhead Recovery Plan (Recovery Plan).
The Hydropower Background Summary covers a range of topics including the history of hydropower, hydropower actions outlined in the Upper Columbia Salmon and Steelhead Recovery Plan, policies and management, an explanation of the nine hydropower projects through which Upper Columbia species must pass, data on juvenile and adult survival through these hydropower projects, and an overview of how hydropower can affect the viability of Upper Columbia spring Chinook and steelhead. Hydropower development on the mainstem Columbia began in the 1930’s with the building of Rock Island Dam (1933) and Bonneville Dams (1938) and continued through the 1960’s with the last mainstem Columbia dam in the U.S. being built in 1979 (Chief Joseph Dam). Construction of Grand Coulee dam in 1942 and Chief Joseph Dam without upstream fish passage cut off over 50% of the habitat of Upper Columbia salmon and steelhead. Almost immediately following construction federal and local public utility district dam owners, managers, and regulators have worked to ensure and improve fish passage.
Since construction of the dams, managers and regulators have worked to ensure adequate fish passage for juveniles and adult salmon, steelhead, and bull trout. Survival of juveniles and adults as they migrate through the reservoirs and dams is affected by numerous environmental and hydrosystem-related factors. Management of the hydrosystem pertains not just to survival through the dams but also survival through the reservoirs that connect them. Existing agreements, plans, and strategies lay out the standards for survival. Public Utilities and Federal Action Agencies are currently meeting these standards or expect to be able to at each of their hydropower projects. Current estimates for Upper Columbia spring Chinook and steelhead indicate that 40-50% of juveniles migrating downstream (to Bonneville Dam tailrace) and 75-80% of adults migrating upstream survive their migration through the hydrosystem. Although much progress has been made to better understand and improve mainstem Columbia migration survival, uncertainties remain that must be considered in future management of the hydrosystem as they pertain to recovery of listed species in the Upper Columbia.
Photo Credit: The Dalles Dam. Photo from USACE