Montour Ash Basin No 1, located in Derry Township, Pennsylvania, is a privately owned earth dam completed in 1971 with a height of 40 feet and a length of 8400 feet. The dam serves a primary purpose classified as "Other" and has a normal storage capacity of 465 acre-feet. With a hazard potential rated as "High" and a condition assessment deemed as "Satisfactory," the dam is under the regulatory jurisdiction of the Pennsylvania Department of Environmental Protection.

The Montour Ash Basin No 1 sits within the watershed of Chillisquaque Creek and is monitored for state permitting, inspection, and enforcement. In 2011, mechanical modifications were made to the dam, ensuring its continued stability and safety. The dam's maximum storage capacity is 5070 acre-feet, with a surface area of 117 acres and a drainage area of 0.2 square miles. Despite its high hazard potential, the dam's condition assessment indicates that it is currently in satisfactory condition, providing a crucial water resource management function in the region.

As an essential part of the water infrastructure in Montour County, Pennsylvania, Montour Ash Basin No 1 plays a vital role in regulating water flow and storage within the region. With its satisfactory condition assessment and regular inspection schedule, the dam ensures the safety of nearby communities and the environment. Monitoring agencies and regulatory bodies work together to uphold the dam's integrity and safeguard against potential risks, highlighting the importance of maintaining a robust water resource management system in the face of changing climate conditions.