Assunpink #20 Dam
Assunpink #20 Dam is an earth dam located in Mercer County, New Jersey. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Assunpink #20 Dam
The primary purpose of Assunpink #20 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 County Of Mercer Park Commission (local government). It impounds the Assunpink Creek.
The dam stands 26 feet tall and stretches 4,070 feet across, creates a reservoir covering 275 acres, has a maximum storage capacity of 14,730 acre-feet, and collects water from a drainage area of 30 square miles.
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 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 04/15/2024.
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 | Mercer |
| River/Stream | Assunpink Creek |
| Coordinates | 40.26670, -74.66273 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 26 ft |
| Dam Height | 26 ft |
| Dam Length | 4,070 ft |
Storage & Hydraulics
| NID Storage | 14,730 acre-ft |
| Max Storage | 14,730 acre-ft |
| Normal Storage | 2,700 acre-ft |
| Surface Area | 275 acres |
| Drainage Area | 30 sq mi |
| Max Discharge | 29,450 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | County of Mercer Park Commission |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/15/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NJ00552 |
| Federal ID | NJ00552 |
| More Info | State Dam Safety Program |