The Lower Columbia Sandy Watershed (HUC 17080001) covers an area of approximately 2,100 square miles in western Oregon. The watershed is characterized by a diverse landscape of mountains, forests, and agricultural lands. The hydrology of the watershed is heavily influenced by snowmelt from the Cascade Mountains, which contributes to the surface water flows of the Sandy River and its tributaries. The watershed is home to several reservoirs, including the Bull Run Reservoir, which is the primary source of drinking water for the city of Portland. The area has experienced significant climate variability in recent years, with above-average snowpack and precipitation in some years and below-average snowpack and drought conditions in others. The watershed has also been impacted by human activities, including logging, agricultural practices, and urban development, which have led to increased sedimentation and habitat loss for fish and wildlife.