Effects of hydropower operations on spawning habitat, rearing habitat, and standing/entrapment mortality of fall Chinook salmon in the Hanford Reach of the Columbia River

This report describes research conducted primarily in 2003 and 2004 to evaluate the effects of upstream dam operations on spawning and rearing conditions for fall Chinook salmon, Oncorhynchus tshawytscha, in the Hanford Reach of the Columbia River. Results from habitat modeling tasks which continued in 2005 and 2006 are also included in this report. This study is focused on the effects of streamflows and streamflow fluctuations on 1) entrapment and entrapment mortality of juveniles, 2) adult spawning habitat, and 3) juvenile rearing habitat. An independent peer review was conducted on the draft version of this report utilizing three reviewers, each with different areas of expertise and different levels of knowledge regarding hydrodynamic modeling, fall Chinook biology, life history, and habitat requirements, and fishery issues relating to hydropower development and operations. Peer review comments have been incorporated into this final version.