Introduction
Recent analyses of PIT tag data suggests that juvenile migration survival is strongly correlated with river temperature (Anderson 2003, Connor et al. 2003, Smith et al. 2003). Because of this relationship there is a renewed interest in the possible value of using cool water releases from reservoirs in the Snake River system to increase survival of the juvenile migrants through the hydrosystem. In this white paper we explore the impact of such temperature control actions on survival of juvenile migrants through the hydrosystem. We examine the relationship of Snake River chinook salmon and steelhead survival to environmental conditions using a water heat budget model and a juvenile passage survival model.