• Adult fish ladders at the dams

    In 2015, adult spring Chinook returns to Bonneville Dam were the fourth highest on record. (Counts go back to 1938, averaging less than 100,000 per year.The highest 4 returns have all been in the past 15 years.)

    Adult fish returning from the ocean to their spawning grounds pass the dams through fish ladders. Snake River chinook and steelhead go through 8 dams (Bonneville to Lower Granite) and Upper Columbia chinook and steelhead go through 4 federal dams (Bonneville to McNary). Upper Columbia stocks also go through public utility-owned dams above McNary. See route here.

    The FCRPS BiOp sets adult fish survival standards for each interior Columbia Basin ESA-listed species. Survival estimates (shown in the chart above) are designed to isolate the effects of dam passage from harvest-related mortality and straying, but unreported harvest and inaccurate stray rates still affect these estimates.

    For 2013 (the most recent year for which we have estimates) three stocks surpassed the BiOp performance standard and two were below it. In 2013, the Corps initiated a two-year adult passage study to better understand and quantify the losses.
    McNary Dam - a fish ladder I 450
    McNary Dam

    Lower Monumental Dam - a fish ladder 380 John Day - a fish ladder 360
    Lower Monumental Dam                                                                              John Day Dam                
    The Dalles Dam - a fish ladder 380 McNary Dam - a fish ladder III 200
    The Dalles Dam                                                                                           McNary Dam
  • Juvenile fish passage

    Juvenile salmon and steelhead pass the dams by many routes - through surface passage and spill, through bypass sytems and turbines. See the surface passage and other routes at each FCRPS dam and the survival estimates based on the most recent scientifically designed tests. All dams are on track to meet the BiOp performance standards for juvenile fish survival, 96 percent for spring chinook and steelhead; 93 percent for summer migrating fish. 


    Bonneville Dam

    The Dalles Dam

    John Day Dam

    McNary Dam

    Ice Harbor Dam

    Lower Monumental Dam

    Little Goose Dam

    Lower Granite Dam

    Adult Survival Standard
    Snake River fall Chinook, Upper Columbia River springChinook and Upper Columbia steelhead all surpassed NOAA Fisheries’ performancestandard for survival through the hydrosystem in 2013 (8 dams for Snake Riverstocks and 4 dams for Upper Columbia stocks). Snake River spring/summer Chinookand Snake River steelhead were below the standard.
    Adult Survival Small
    (Click here for larger size)