Mountain Lake Dam is an earth dam located in Hampden County, Massachusetts, built in 1923. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 32 ft32 ft tall and 250 ft long, taller than 74% of U.S. dams with a recorded height. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Mountain Lake Dam
The primary purpose of Mountain Lake Dam is flood risk reduction. The dam is designed to control downstream flooding by temporarily storing excess water during storms and releasing it at a controlled rate. The dam is owned by City of Chicopee (local government). It impounds the Willimansett Brook, Tributary of Chicopee River near Chicopee.
The dam stands 32 feet tall and stretches 250 feet across, has a maximum storage capacity of 74 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1923, 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 11/14/2023.
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 | Hampden |
| Nearest City | Chicopee |
| River/Stream | Willimansett Brook, Tributary of Chicopee River |
| Coordinates | 42.19294, -72.58492 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 32 ft |
| Dam Length | 250 ft |
| Year Completed | 1923 (103 years old) |
Storage & Hydraulics
| NID Storage | 74 acre-ft |
| Max Storage | 74 acre-ft |
| Drainage Area | 2 sq mi |
| Max Discharge | 1,735 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Flood Risk Reduction |
| Owner | City of Chicopee |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/14/2023 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00530 |
| Federal ID | MA00530 |
| More Info | State Dam Safety Program |