Pleasant Lake Dam
Pleasant Lake Dam is an earth dam located in Merrimack County, New Hampshire, built in 1850. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Pleasant Lake Dam
The primary purpose of Pleasant Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town Of New London (local government). It impounds the Tr Blackwater River near New London.
The dam stands 13 feet tall and stretches 360 feet across, creates a reservoir covering 604 acres, has a maximum storage capacity of 9,295 acre-feet, and collects water from a drainage area of 11 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 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. 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 07/07/2021.
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 | Merrimack |
| Nearest City | New London |
| River/Stream | Tr Blackwater River |
| Coordinates | 43.42037, -71.93940 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 360 ft |
| Year Completed | 1850 (176 years old) |
Storage & Hydraulics
| NID Storage | 9,295 acre-ft |
| Max Storage | 9,295 acre-ft |
| Normal Storage | 6,806 acre-ft |
| Surface Area | 604 acres |
| Drainage Area | 11 sq mi |
| Max Discharge | 1,689 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | TOWN OF NEW LONDON |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 07/07/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | NH00362 |
| Federal ID | NH00362 |
| More Info | State Dam Safety Program |