The effects of two large scale fish bypass systems on salmonid passage and survival on the mid-Columbia River

Salmonid migration on the Columbia River in the Pacific Northwest was initially impeded in 1933 with the completion of Rock Island Dam.  Subsequently, 13 additional hydropower facilities have been installed throughout the Columbia River Basin.  Fish experience direct injury and mortality from physically passing dams (turbines/spillway) and also indirect mortality due to the effects dams on the environment (i.e. habitat alterations leading to increased predation by birds and piscivorous fishes).  Improving fish passage throughout the Columbia Basin has been a high priority for over three decades for both downstream migrating juvenile salmonids as well as upstream migrating adults.  To improve fish passage, many hydropower facilities have undertaken major construction projects to build effective fish bypass systems.  On the mid-Columbia River, Grant County PUD has designed, built, and installed two juvenile fish bypass systems over the past 6 years.  Both systems provide migrating juvenile salmonids an efficient alternative to turbine or spillway passage.   Data presented will highlight fish passage behavior and survival at both projects before and after the installation of fish bypass systems.   In addition data will be presented on the efforts being made to curb indirect mortality from birds and piscivorous fishes.