Snake River Juvenile Salmon Transportation Program: An Overview of a Long-Term Hydropower Mitigation Effort

The US Army Corps of Engineers has been transporting juvenile salmonids downstream through the Snake and Columbia River hydro power system in barges and trucks since 1981 as mitigation for the impacts of hydropower dam construction and operations.  Criticism of this mitigation effort has focused on its overall efficacy, cost and unintended consequences including elevated stray rates and differential delayed mortality.    Long-term research, monitoring, and evaluation of the transportation program has guided adaptive management of transport operations and modification and replacement of infrastructure.  Comparisons of fish survival to adulthood for juveniles transported versus those migrating in-river is compared throughout the migration season to evaluate temporal periods when transportation provides a survival benefit.   Transportation continues to be an important tool in the recovery of Snake River salmon and steelhead.  Operational and configuration changes in dams and the hydrosystem are continuing and have been successful in reducing hydrosystem effects on salmon and steelhead populations.  With continuing improvements we hope to eliminate the need for this extensive mitigation program.