The Hells Canyon Watershed, located in the Pacific Northwest, covers an area of approximately 9,220 square miles. Hydrologically, the watershed is characterized by the Snake River, which runs through Hells Canyon, the deepest river gorge in North America. The area receives significant snowfall in the winter months, with the highest snowpacks occurring in the higher elevations of the watershed. The surface water in the watershed is primarily used for agricultural purposes and hydroelectric power generation. The reservoirs in the area are key components of the hydroelectric power systems and contain significant quantities of sediment and nutrients. Interesting climatic facts include the occurrence of regular winter inversions in the lower elevations, leading to poor air quality, and the occurrence of significant wildfires in recent years due to a combination of drought and human activity. Climate change is expected to result in reduced snowpack and increased frequency of extreme weather events in the region.