Lower Great Falls
Lower Great Falls is a masonry dam located in Strafford County, New Hampshire, built in 1984. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
About Lower Great Falls
The primary purpose of Lower Great Falls is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. It impounds the Salmon Falls River near Rollinsford.
The dam stands 36 feet tall and stretches 270 feet across, creates a reservoir covering 32 acres, has a maximum storage capacity of 472 acre-feet, and collects water from a drainage area of 220 square miles. Completed in 1984, the structure is 42 years old.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 05/19/2022.
At 36 feet, this dam is taller than 83% of dams nationwide.
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Location
| State | New Hampshire |
| County | Strafford |
| Nearest City | Rollinsford |
| River/Stream | Salmon Falls River |
| Coordinates | 43.25440, -70.84460 |
Physical Characteristics
| Dam Type | Masonry |
| NID Height | 36 ft |
| Dam Height | 36 ft |
| Dam Length | 270 ft |
| Year Completed | 1984 (42 years old) |
Storage & Hydraulics
| NID Storage | 472 acre-ft |
| Max Storage | 472 acre-ft |
| Normal Storage | 472 acre-ft |
| Surface Area | 32 acres |
| Drainage Area | 220 sq mi |
| Max Discharge | 8,460 cfs |
| Spillway Type | Controlled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner Type | Not Listed |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/19/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00126 |
| Federal ID | NH00126 |
| More Info | State Dam Safety Program |