Lost Lake Dam
Lost Lake Dam is a concrete dam located in Middlesex County, Massachusetts, built in 1910. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Lost Lake Dam
The primary purpose of Lost 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 Groton (local government). It impounds the Martin's Pond Brook near Groton.
The dam stands 10 feet tall and stretches 100 feet across, creates a reservoir covering 300 acres, has a maximum storage capacity of 1,960 acre-feet, and collects water from a drainage area of 5 square miles. Completed in 1910, the structure is over a century 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. 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 05/05/2023.
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 Massachusetts 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 | Massachusetts |
| County | Middlesex |
| Nearest City | Groton |
| River/Stream | Martin's Pond Brook |
| Coordinates | 42.60070, -71.51825 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 10 ft |
| Dam Length | 100 ft |
| Year Completed | 1910 (116 years old) |
Storage & Hydraulics
| NID Storage | 1,960 acre-ft |
| Max Storage | 1,960 acre-ft |
| Normal Storage | 1,500 acre-ft |
| Surface Area | 300 acres |
| Drainage Area | 5 sq mi |
| Max Discharge | 200 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Groton |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 05/05/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00808 |
| Federal ID | MA00808 |
| More Info | State Dam Safety Program |