The Big Fork Watershed (HUC 09030006) covers a land area of approximately 1,717 square miles in northwest Montana. The hydrology of the watershed is dominated by the Flathead River, which is fed by numerous tributaries, including the Big Fork River. Snowpack is a significant contributor to surface water in the watershed, with an average annual snowfall of 120 inches. Surface water in the watershed is used for a variety of purposes, including irrigation and recreation. The reservoirs in the Big Fork Watershed are primarily used for hydroelectric power generation. Interesting climatic facts include the presence of a Mediterranean climate in some parts of the watershed, which is characterized by hot, dry summers and mild, wet winters. Climate change is expected to impact the snowpack and water availability in the watershed, with potentially significant consequences for agriculture, forest health, and other ecosystem services.