Manahawkin Lake Dam
Manahawkin Lake Dam is an earth dam located in Ocean County, New Jersey, built in 1929. It carries a Significant hazard potential classification and has a poor condition assessment.
About Manahawkin Lake Dam
The primary purpose of Manahawkin Lake 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 Ocean (local government). It impounds the Mill Creek near Manahawkin.
The dam stands 12 feet tall and stretches 900 feet across, creates a reservoir covering 54 acres, has a storage capacity of 127 acre-feet, and collects water from a drainage area of 19 square miles. Completed in 1929, 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 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 09/15/2023.
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Location
| State | New Jersey |
| County | Ocean |
| Nearest City | Manahawkin |
| River/Stream | Mill Creek |
| Coordinates | 39.69623, -74.25948 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 12 ft |
| Dam Height | 12 ft |
| Dam Length | 900 ft |
| Year Completed | 1929 (97 years old) |
Storage & Hydraulics
| NID Storage | 127 acre-ft |
| Normal Storage | 127 acre-ft |
| Surface Area | 54 acres |
| Drainage Area | 19 sq mi |
| Max Discharge | 1,908 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | County of Ocean |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 09/15/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00057 |
| Federal ID | NJ00057 |
| More Info | State Dam Safety Program |