Otter Brook Dam
Otter Brook Dam is a gravity dam located in Cheshire County, New Hampshire, built in 1958. It carries a High hazard potential classification.
About Otter Brook Dam
The primary purpose of Otter Brook 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 Otter Brook near Keene.
The dam stands 119 feet tall and stretches 1,288 feet across, creates a reservoir covering 76 acres, has a maximum storage capacity of 24,800 acre-feet, and collects water from a drainage area of 47 square miles. Completed in 1958, 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. An emergency action plan is in place for this dam. The most recent inspection on record was 11/07/2022.
At 119 feet, this dam is taller than 98% 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 | Keene |
| River/Stream | Otter Brook |
| Coordinates | 42.94648, -72.23666 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 119 ft |
| Dam Height | 119 ft |
| Dam Length | 1,288 ft |
| Year Completed | 1958 (68 years old) |
Storage & Hydraulics
| NID Storage | 24,800 acre-ft |
| Max Storage | 24,800 acre-ft |
| Normal Storage | 870 acre-ft |
| Surface Area | 76 acres |
| Drainage Area | 47 sq mi |
| Max Discharge | 34,500 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 | 11/07/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00006 |
| Federal ID | NH00006 |
| More Info | State Dam Safety Program |