The Lower Grande Ronde Watershed covers an area of approximately 1,805 square miles in northeastern Oregon. It is primarily composed of steep, forested mountainous terrain, with the Grande Ronde River serving as the main drainage outlet. The watershed experiences a semi-arid climate, with the majority of precipitation occurring as snow in the winter months. The snowpack is an important component of the hydrology of the watershed, as it provides a significant portion of the water supply for the region. Surface water in the watershed is characterized by high-quality coldwater streams that support a variety of fish species, including steelhead and Chinook salmon. There are several reservoirs in the watershed, including the Catherine Creek Reservoir and the Grande Ronde Reservoir, which provide irrigation water and hydropower generation. Climatic trends in the region include increasing temperatures and decreasing snowpack, which could have significant impacts on water resources in the future.