Alder Marsh, located in Lebanon Township, Pennsylvania, is a state-regulated Earth dam completed in 1948 with a primary purpose of recreation. This dam, standing at a height of 10 feet and a length of 175 feet, has a storage capacity of 266 acre-feet and a normal storage of 78 acre-feet. The dam is situated on Alder Marsh Brook and is under the jurisdiction of the Pennsylvania Department of Environmental Protection.

Despite its fair condition assessment, Alder Marsh poses a high hazard potential due to its location and design. With a drainage area of 0.91 square miles, this dam plays a crucial role in managing water resources in the area and providing recreational opportunities for the community. The dam's maintenance and inspection are regularly carried out by the state, ensuring its structural integrity and safety for the surrounding environment.

Alder Marsh serves as a vital infrastructure for water resource management and recreation in Wayne County, Pennsylvania. As a regulated state dam, it underscores the importance of sustainable water practices and ecosystem preservation in the face of climate change challenges. With its historical significance and ongoing maintenance efforts, Alder Marsh stands as a testament to the intersection of water resource management and environmental stewardship in the region.