Johnston is a privately owned dam located in Allegheny Township, Butler County, Pennsylvania. Built in 1978, this Earth dam stands at 26 feet tall and spans a length of 925 feet, containing a storage capacity of 281 acre-feet of water for recreational purposes. Situated on TR Carrs Run, a small stream with a drainage area of 0.42 square miles, Johnston provides a surface area of 20 acres for recreational activities.

Managed by the Pennsylvania Department of Environmental Protection, Johnston is regulated, permitted, inspected, and enforced by the state to ensure its safety and compliance with regulations. With a low hazard potential and a condition assessment that is not rated, this dam serves as a recreational resource for the local community. Despite not having an Emergency Action Plan (EAP) in place currently, Johnston maintains a relatively low risk profile, emphasizing the importance of ongoing monitoring and maintenance to ensure the safety of its surrounding area.

Overall, Johnston in Butler County, Pennsylvania, is a modest-sized dam that offers recreational opportunities while also being subject to state regulations and inspections. With a focus on public safety and risk management, the dam continues to provide valuable recreational amenities to the local community while emphasizing the need for ongoing monitoring and maintenance to ensure its continued safe operation.