The Atison Lake Dam is an earthen embankment originally constructed around 1800. The spillway was reconstructed in 1930, 1934, and 1944 and again in 2009. In accordance with NJDEP files, the Atison Lake Dam is classified as a Class I, High Hazard Potential dam with reduced Spillway Design Flood (SDF) to ½ PMP based on a Phase II Inspection Report.​

​Van Cleef performed a formal Inspection Report. The inspection report indicated that the newly rehabilitated structure was in good condition and required no immediate repairs or long-term improvements.