The Thornapple Watershed (HUC 04050007) covers approximately 174 square miles in west-central Michigan. The hydrology of the watershed is dominated by the Thornapple River and its tributaries, which provide a significant source of surface water for the region. The watershed experiences significant snowpack during the winter months, with an average snowfall of around 50 inches per year. Surface water in the Thornapple watershed is primarily used for recreational activities, such as fishing and boating, as well as for agricultural purposes. Reservoir constituents in the Thornapple watershed include nutrients, sediment, and other pollutants, which can have significant impacts on water quality and aquatic ecosystems. Climate trends in the region include increasing temperatures and more frequent extreme weather events, such as heavy rainfall and flooding. These trends can exacerbate the impacts of pollution and other environmental stressors on the watershed. Overall, the Thornapple watershed is an important resource for both local communities and the broader region, and efforts are ongoing to protect and improve its water quality and ecological health.