Prospertown Dam
Prospertown Dam is an earth dam located in Ocean County, New Jersey, built in 1966. It carries a High hazard potential classification and has a poor condition assessment.
About Prospertown Dam
The primary purpose of Prospertown Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by Division Of Fish & Wildlife (state). It impounds the Lahaway Creek near Upper Freehold Township.
The dam stands 19 feet tall and stretches 550 feet across, creates a reservoir covering 70 acres, has a maximum storage capacity of 490 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1966, the structure is well into its service life at over 50 years 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 10/23/2024.
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 | Ocean |
| Nearest City | Upper Freehold Township |
| River/Stream | Lahaway Creek |
| Coordinates | 40.13317, -74.46060 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 19 ft |
| Dam Height | 19 ft |
| Dam Length | 550 ft |
| Year Completed | 1966 (60 years old) |
Storage & Hydraulics
| NID Storage | 490 acre-ft |
| Max Storage | 490 acre-ft |
| Normal Storage | 402 acre-ft |
| Surface Area | 70 acres |
| Drainage Area | 3 sq mi |
| Max Discharge | 834 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | Division of Fish & Wildlife |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 10/23/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00455 |
| Federal ID | NJ00455 |
| More Info | State Dam Safety Program |