Surry Mountain Dam
Surry Mountain Dam is a rockfill dam located in Cheshire County, New Hampshire, built in 1941. It carries a High hazard potential classification.
About Surry Mountain Dam
The primary purpose of Surry Mountain 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 Usace - New England District (federal). It impounds the Ashuelot River near Surry.
The dam stands 83 feet tall and stretches 1,800 feet across, creates a reservoir covering 260 acres, has a maximum storage capacity of 44,000 acre-feet, and collects water from a drainage area of 100 square miles. Completed in 1941, the structure is well-established, with more than 75 years of service.
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. An emergency action plan is in place for this dam. The most recent inspection on record was 06/01/2023.
At 83 feet, this dam is taller than 97% of all dams in the United States.
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 | Cheshire |
| Nearest City | Surry |
| River/Stream | Ashuelot River |
| Coordinates | 42.99778, -72.30926 |
Physical Characteristics
| Dam Type | Rockfill |
| NID Height | 83 ft |
| Dam Height | 83 ft |
| Dam Length | 1,800 ft |
| Year Completed | 1941 (85 years old) |
Storage & Hydraulics
| NID Storage | 44,000 acre-ft |
| Max Storage | 44,000 acre-ft |
| Normal Storage | 1,320 acre-ft |
| Surface Area | 260 acres |
| Drainage Area | 100 sq mi |
| Max Discharge | 50,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - New England District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not Available |
| Last Inspection | 06/01/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00007 |
| Federal ID | NH00007 |
| More Info | State Dam Safety Program |