Edward Macdowell Dam is an earth dam located in Hillsborough, New Hampshire, built in 1950. It carries a High hazard potential classification.
Dam profile
NID height · 63 ft63 ft tall and 1,100 ft long, taller than 95% of U.S. dams with a recorded height. Height is drawn to scale against a ten-story building, about 100 ft; the profile is a generic embankment section and the water level is illustrative.
About Edward Macdowell Dam
The primary purpose of Edward Macdowell 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 Nubanusit Brook near Peterborough.
The dam stands 63 feet tall and stretches 1,100 feet across, creates a reservoir covering 165 acres, has a maximum storage capacity of 31,600 acre-feet, and collects water from a drainage area of 44 square miles. Completed in 1950, 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 06/06/2023.
At 63 feet, this dam is taller than 95% 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 | Hillsborough |
| Nearest City | Peterborough |
| River/Stream | Nubanusit Brook |
| Coordinates | 42.89395, -71.98640 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 63 ft |
| Dam Height | 63 ft |
| Dam Length | 1,100 ft |
| Year Completed | 1950 (76 years old) |
Storage & Hydraulics
| NID Storage | 31,600 acre-ft |
| Max Storage | 31,600 acre-ft |
| Normal Storage | 150 acre-ft |
| Surface Area | 165 acres |
| Drainage Area | 44 sq mi |
| Max Discharge | 17,800 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | USACE - New England District |
| Owner Type | Federal |
| Hazard Classification | High |
| Condition Assessment | Not assessed |
| Last Inspection | 06/06/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00005 |
| Federal ID | NH00005 |
| More Info | State Dam Safety Program |