Klamath River Impoundments, Oregon & California

PacifiCorp operates several hydropower facilities on the Klamath River, starting in southern Oregon and extending down to northern California. MaxDepth Aquatics was contracted to characterize the fisheries in Copco and Iron Gate Reservoirs. J. Eilers served as principal investigator for studies of the bathymetry for all impoundments in the project (Ewauna, Keno, JC Boyle, Copco, and Iron Gate) and the reach of water between Ewauna and Keno. In addition, J. Eilers has supervised studies of sediment oxygen demand throughout the project area.

Iron Gate and Copco Reservoirs are the terminal impoundments in PacifiCorps’s Klamath Hydroelectric Project located on the Klamath River in northern California. As part of the FERC relicensing activities for the Project, PacifiCorp contracted with MaxDepth Aquatics to assess the fisheries abundance and distribution in the deeper water habitats of the impoundments.

MaxDepth crews surveyed the two impoundments in August and October 2003 and April 2004 using a BioSonics split-beam hydroacoustic unit to provide information on the fish communities. The results not only documented the sparse fish abundance, but also revealed the short-term release of gas from the sediment during fall turnover in Copco Reservoir.