Powder Mill
Powder Mill is a concrete dam located in Hillsborough, New Hampshire, built in 1924. It carries a Low hazard potential classification and has a satisfactory condition assessment.
About Powder Mill
The primary purpose of Powder Mill is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Monadnock Paper Mills, Inc. (private). It impounds the Contoocook River near Bennington.
The dam stands 21 feet tall and stretches 366 feet across, creates a reservoir covering 435 acres, has a maximum storage capacity of 8,600 acre-feet, and collects water from a drainage area of 184 square miles. Completed in 1924, the structure is over a century old.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 06/15/2017.
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Location
| State | New Hampshire |
| County | Hillsborough |
| Nearest City | Bennington |
| River/Stream | Contoocook River |
| Coordinates | 42.99270, -71.92420 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 21 ft |
| Dam Height | 21 ft |
| Dam Length | 366 ft |
| Year Completed | 1924 (102 years old) |
Storage & Hydraulics
| NID Storage | 8,600 acre-ft |
| Max Storage | 8,600 acre-ft |
| Normal Storage | 2,400 acre-ft |
| Surface Area | 435 acres |
| Drainage Area | 184 sq mi |
| Max Discharge | 18,200 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Monadnock Paper Mills, Inc. |
| Owner Type | Private |
| Hazard Classification | Low |
| Condition Assessment | Satisfactory |
| Last Inspection | 06/15/2017 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NH00248 |
| Federal ID | NH00248 |
| More Info | State Dam Safety Program |