The Pend Oreille Watershed (HUC 17010216) covers an area of approximately 2,900 square miles in Idaho, Montana, and Washington. The hydrology of the region is dominated by the Pend Oreille River, which is fed by numerous tributaries and has a drainage basin of over 13,000 square miles. The region experiences significant snowpack accumulation, with the highest levels typically occurring in the Selkirk Mountains in the north. Surface water quality is good overall, but there are some areas of concern due to agricultural runoff and other factors. There are several reservoirs in the watershed, including Box Canyon Reservoir and Boundary Reservoir, which are used for hydroelectric power generation and recreation. Interesting climatic facts and trends in the region include a trend towards decreasing snowpack levels in recent years, as well as increasing average temperatures and more frequent extreme weather events.