Hydroacoustic evaluation of steelhead fallback and kelt passage at the dalles dam in 2008/2009 and 2009/2010

The ice and trash sluiceway at The Dalles Dam on the Columbia River is opened from April through December each year to provide a non-turbine passage route for salmonids.  The sluiceway is capable of passing juvenile salmonids migrating downstream, as well as upstream migrants that fall back downstream after passing up a fish ladder and steelhead kelts migrating downstream to the ocean after spawning.  However, sluiced water is unavailable for hydroelectric generation.  To optimize the trade-off between fish passage conditions and power production, fisheries and dam managers need information about rates of adult salmon passage over time and space.  Therefore, we conducted hydroacoustic studies in 2008/2009 and 2009/2010 to characterize adult steelhead spatial and temporal distributions and passage rates at the sluiceway.  The study is still in the data collection and analysis phase.  A preliminary report is due in May 2010.  Expected results include run timing, passage rates, horizontal distribution, and passage efficiency of the sluiceway for adult steelhead.  Results from the two study periods will be compared to identify consistencies and differences.  The data will be applied to decisions on sluiceway operations.