PENNSYLVANIA RESERVOIR REPORT

Last Updated: December 5, 2025

Pennsylvania has more than 3,000 dams and the majority of them are used for flood control, irrigation and recreational purposes. Some of the major reservoirs in the state are Raystown Lake, Lake Wallenpaupack, and Blue Marsh Lake. These reservoirs are supplied by streams, rivers and creeks such as the Juniata River and the Lackawaxen River. The snowpack in the Pocono Mountains and the Allegheny Mountains contributes to the water supply of these reservoirs. The hydrology in the area is influenced by the Appalachian Mountains and the Atlantic Ocean. The state has experienced record low water levels in some reservoirs during drought conditions. Seasonal trends show that water levels are typically highest in the spring due to snowmelt and lowest in the fall. Overall, these reservoirs play a crucial role in supplying water for the state's agriculture, industries and residents.

Pennsylvania has more than 3,000 dams and the majority of them are used for flood control, irrigation and recreational purposes. Some of the major reservoirs in the state are Raystown Lake, Lake Wallenpaupack, and Blue Marsh Lake. These reservoirs are supplied by streams, rivers and creeks such as the Juniata River and the Lackawaxen River. The snowpack in the Pocono Mountains and the Allegheny Mountains contributes to the water supply of these reservoirs. The hydrology in the area is influenced by the Appalachian Mountains and the Atlantic Ocean. The state has experienced record low water levels in some reservoirs during drought conditions. Seasonal trends show that water levels are typically highest in the spring due to snowmelt and lowest in the fall. Overall, these reservoirs play a crucial role in supplying water for the state's agriculture, industries and residents.