Lower Mountain Lake Dam
Lower Mountain Lake Dam is an earth dam located in Mercer County, New Jersey. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Lower Mountain Lake Dam
The primary purpose of Lower Mountain Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Princeton (local government). It impounds the Stony Brook-tr near Lawrence.
The dam stands 13 feet tall and stretches 270 feet across, creates a reservoir covering 6 acres, has a maximum storage capacity of 25 acre-feet, and collects water from a drainage area of 1 square miles.
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 11/25/2024.
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Location
| State | New Jersey |
| County | Mercer |
| Nearest City | Lawrence |
| River/Stream | Stony Brook-tr |
| Coordinates | 40.36047, -74.67568 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 270 ft |
Storage & Hydraulics
| NID Storage | 25 acre-ft |
| Max Storage | 25 acre-ft |
| Normal Storage | 15 acre-ft |
| Surface Area | 6 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 1,000 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Princeton |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/25/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00747 |
| Federal ID | NJ00747 |
| More Info | State Dam Safety Program |