Big Spring, located in St. Clair Township, Pennsylvania, is a vital water supply dam that has been serving the community since its completion in 1907. With a height of 43 feet and a length of 1000 feet, this earth dam holds a maximum storage capacity of 161 acre-feet and a normal storage of 129 acre-feet. It sits on the Big Spring Run, within the Westmoreland County, and covers a surface area of 6 acres, with a drainage area of 1.16 square miles.

Managed by the Pennsylvania Department of Environmental Protection, Big Spring is regulated, inspected, and enforced by the state authorities to ensure its structural integrity and safety. The dam has a high hazard potential, yet it has been assessed to be in satisfactory condition. Its last inspection in October 2020 confirmed its operational readiness, with an inspection frequency of once per year. Although no emergency action plan has been reported, the dam continues to meet guidelines and is in compliance with regulatory standards.

For water resource and climate enthusiasts, Big Spring serves as a crucial infrastructure for water supply in the region. Its historical significance, combined with its ongoing management and maintenance, underscores the importance of balancing water resource development with environmental protection. As a key component of the local government's water management strategy, Big Spring exemplifies the intersection of human needs and natural ecosystems, highlighting the complexities and challenges of sustainable water resource management in a changing climate.