Souhegan River Site 33 Dam
Souhegan River Site 33 Dam is an earth dam located in Hillsborough, New Hampshire, built in 1971. It carries a High hazard potential classification and has a fair condition assessment.
About Souhegan River Site 33 Dam
The primary purpose of Souhegan River Site 33 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 Nh Des Water Division (state). It impounds the King Brook near Wilton.
The dam stands 21 feet tall and stretches 510 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 900 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1971, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 10/25/2022.
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 Hampshire 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 Hampshire |
| County | Hillsborough |
| Nearest City | Wilton |
| River/Stream | King Brook |
| Coordinates | 42.86110, -71.74940 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 21 ft |
| Dam Height | 21 ft |
| Dam Length | 510 ft |
| Year Completed | 1971 (55 years old) |
Storage & Hydraulics
| NID Storage | 900 acre-ft |
| Max Storage | 900 acre-ft |
| Normal Storage | 24 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 1 sq mi |
| Max Discharge | 2,100 cfs |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | NH DES WATER DIVISION |
| Owner Type | State |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 10/25/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00265 |
| Federal ID | NH00265 |
| More Info | State Dam Safety Program |