The Nooksack watershed, located in northwestern Washington State, encompasses approximately 1,470 square miles of land area. The watershed is characterized by a diverse hydrology, with precipitation falling as both rain and snow. Snowpack accumulation in the winter and spring is critical for maintaining summer streamflow, which supports a variety of aquatic species and human uses such as irrigation and drinking water supply. The watershed contains several large reservoirs, including the Baker River Reservoir, which provides hydroelectric power and recreational opportunities. Climate trends in the Nooksack watershed have included increased winter precipitation and streamflow, as well as earlier snowmelt and peak streamflows. These changes may have implications for water availability and timing of snowmelt-dependent activities such as skiing and tourism. Additionally, the watershed is home to several endangered species, including the Nooksack dace and Chinook salmon.