Diamond Mill Pond Dam
Diamond Mill Pond Dam is an earth dam located in Essex County, New Jersey, built in 1937. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Diamond Mill Pond Dam
The primary purpose of Diamond Mill Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by County Of Essex Department Of Public Works (local government). It impounds the Rahway River near Millburn.
The dam stands 9 feet tall and stretches 375 feet across, creates a reservoir covering 4 acres, has a maximum storage capacity of 24 acre-feet, and collects water from a drainage area of 7 square miles. Completed in 1937, the structure is well-established, with more than 75 years of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 03/14/2024.
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Location
| State | New Jersey |
| County | Essex |
| Nearest City | Millburn |
| River/Stream | Rahway River |
| Coordinates | 40.73112, -74.30710 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 9 ft |
| Dam Height | 9 ft |
| Dam Length | 375 ft |
| Year Completed | 1937 (89 years old) |
Storage & Hydraulics
| NID Storage | 24 acre-ft |
| Max Storage | 24 acre-ft |
| Normal Storage | 11 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 7 sq mi |
| Max Discharge | 1,940 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | County of Essex Department of Public Works |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 03/14/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00926 |
| Federal ID | NJ00926 |
| More Info | State Dam Safety Program |