Black Reservoir Dam is a concrete dam located in Cheshire County, New Hampshire, built in 1850. It carries a Significant hazard potential classification and has a poor condition assessment.
Dam profile
NID height · 10 ft10 ft tall and 180 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic concrete gravity section and the water level is illustrative.
About Black Reservoir Dam
The primary purpose of Black Reservoir Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Nh Des Water Division (state). It impounds the Willow Brook near Jaffrey.
The dam stands 10 feet tall and stretches 180 feet across, creates a reservoir covering 48 acres, has a maximum storage capacity of 253 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1850, the structure is one of the older dams in the region, with over a century and a half of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 09/02/2022.
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Location
| State | New Hampshire |
| County | Cheshire |
| Nearest City | Jaffrey |
| River/Stream | Willow Brook |
| Coordinates | 42.79000, -71.97989 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 10 ft |
| Dam Height | 10 ft |
| Dam Length | 180 ft |
| Year Completed | 1850 (176 years old) |
Storage & Hydraulics
| NID Storage | 253 acre-ft |
| Max Storage | 253 acre-ft |
| Normal Storage | 109 acre-ft |
| Surface Area | 48 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 580 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Nh Des Water Division |
| Owner Type | State |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 09/02/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00497 |
| Federal ID | NH00497 |
| More Info | State Dam Safety Program |