PENNSYLVANIA RESERVOIR REPORT

Last Updated: December 24, 2025

Pennsylvania's dams and reservoirs play a critical role in water supply, flood control, and recreation. The latest observations indicate that most reservoirs are at or near their average storage levels. Prompton Reservoir, General Edgar Jadwin Reservoir, and Lake Arthur at Moraine State Park are observed to have water surface elevations close to their respective averages, with Prompton Reservoir being slightly below average at an elevation of 1125 feet, compared to its average of 1125.34 feet. General Edgar Jadwin Reservoir is slightly above its average, at 990 feet compared to the average of 989.21 feet, while Lake Arthur maintains equilibrium, matching its average elevation of 1190.19 feet. These conditions suggest stable reservoir operations and controlled water management practices.

However, some deviations from the norm are noted. Beltzville Lake near Parryville and Blue Marsh Lake are reporting levels below their average elevations, with Beltzville Lake measuring at 625 feet against an average of 627.57 feet and Blue Marsh Lake at 285 feet, falling short of its 287.91 feet average. The most significant deviation is seen at the Indian Rock Dam, with its water surface at a concerning 371 feet, well below the average of 375.38 feet. These conditions potentially point to a reduced snowpack or lower river inflows, which may affect water availability if persistent. These anomalies could be related to shifts in seasonal weather patterns, water usage policies, or ecological changes documented in sources such as the 2025 Pennsylvania Soybean Yield Contest Winners announcement by GlobeNewswire, which might indirectly reflect on agricultural water demand and regional hydrological changes. It is essential to continue monitoring these reservoirs and investigating the causes of these abnormal conditions to manage potential impacts on water supply and ecosystem health.

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.