The Puget Sound watershed covers approximately 12,000 square miles in western Washington State. It is characterized by a complex hydrology that includes more than 40 freshwater streams and rivers. The region experiences high levels of rainfall, particularly during the winter months, which contributes to its lush vegetation and diverse wildlife. The snowpack in the Cascades Mountains is a critical source of water for the region, particularly during the dry summer months. Surface water in the Puget Sound watershed is impacted by a variety of constituents, including nutrients, sediment, and organic matter, which can negatively impact aquatic habitats. Climate change is expected to have significant impacts on the region, including changes in precipitation patterns and sea-level rise. Efforts to protect and restore the Puget Sound watershed are ongoing, including initiatives to improve water quality and restore habitat for endangered species.