The Raystown watershed (HUC 02050303) covers an area of approximately 1,020 square miles in central Pennsylvania. The hydrology of the area is characterized by steep mountainous terrain, which leads to rapid runoff during heavy rain events. The watershed is also influenced by seasonal snowpack that contributes to the surface water supply during the spring and early summer months. Surface water in the Raystown watershed is primarily sourced from the Raystown Branch of the Juniata River, which flows through the Raystown Lake Reservoir. The reservoir is used for flood control, recreation, and water supply purposes. The constituents of the Raystown Lake Reservoir are influenced by a variety of factors, including land use practices, agricultural runoff, and atmospheric deposition. In recent years, the Raystown watershed has experienced an increase in extreme precipitation events, which has led to flooding and erosion in some areas. Climate projections suggest that the region will continue to experience more frequent and intense precipitation events in the future.