Salish Sea Ecosystem Conference

Forecasted flow and temperature changes in fish-bearing streams of the Hood Canal and Strait of Juan de Fuca

Critical freshwater fish spawning and rearing habitats in western Washington State are sensitive to environmental changes. Concern is growing among tribes and other natural resources managers over the impacts that climate change might have on economically and culturally important fish populations. In 2016, the Point No Point Treaty Council initiated a multi-stage project which aims to forecast stream flow and stream temperature changes throughout the 21st century for fish-bearing watersheds which drain into the Hood Canal and eastern Strait of Juan de Fuca. The high-resolution Distributed Hydrology Soil Vegetation model (DHSVM) and coupled RBM stream temperature model are used to simulate hydrological conditions in select watersheds. Publically available gridded meteorology data (Livneh et al., 2013) and climate forecasts downscaled using the multivariate adaptive constructed analogs method (MACA; Abatzoglou and Brown, 2012) for 10 climate models under two emissions scenarios are used as forcings for the hydrology simulations. Presented and discussed here are stream flow and preliminary stream temperature forecast results for the high-relief and mountainous Big Quilcene River watershed and the relatively low-lying and smaller Tarboo Creek watershed. Topography and watershed relief play an important role in western Washington hydrology and we contrast the forecasted impacts of climate change on the two watersheds as an example of how climate impacts may vary within a similar geographic region. Areas of particular climate sensitivity are identified so that natural resources managers and planners can be better prepared for the future.