Macopin Reservoir Dam
Macopin Reservoir Dam is a stone dam located in Morris County, New Jersey, built in 1892. It carries a High hazard potential classification and has a poor condition assessment.
About Macopin Reservoir Dam
The primary purpose of Macopin Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Newark, Department Of Water And Sewer Utilities (local government). It impounds the Pequannock River.
The dam stands 34 feet tall and stretches 434 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 206 acre-feet, and collects water from a drainage area of 63 square miles. Completed in 1892, the structure is over a century old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 10/18/2024.
At 34 feet, this dam is taller than 80% of dams nationwide.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The New Jersey dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | New Jersey |
| County | Morris |
| River/Stream | Pequannock River |
| Coordinates | 41.01977, -74.40287 |
Physical Characteristics
| Dam Type | Stone |
| NID Height | 34 ft |
| Dam Height | 34 ft |
| Dam Length | 434 ft |
| Year Completed | 1892 (134 years old) |
Storage & Hydraulics
| NID Storage | 206 acre-ft |
| Max Storage | 206 acre-ft |
| Normal Storage | 101 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 63 sq mi |
| Max Discharge | 17,600 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Newark, Department of Water and Sewer Utilities |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/18/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00320 |
| Federal ID | NJ00320 |
| More Info | State Dam Safety Program |