Mountain Street Reservoir Dam
Mountain Street Reservoir Dam is an earth dam located in Hampshire County, Massachusetts, built in 1902. It carries a High hazard potential classification and has a fair condition assessment.
About Mountain Street Reservoir Dam
The primary purpose of Mountain Street Reservoir Dam is water supply. The dam stores water for municipal, industrial, or agricultural use, helping ensure a reliable supply for the surrounding area. The dam is owned by City Of Northampton (local government). It impounds the Beaver Brook near Williamsburg.
The dam stands 33 feet tall and stretches 1,300 feet across, creates a reservoir covering 20 acres, has a maximum storage capacity of 761 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1902, 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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 07/27/2022.
At 33 feet, this dam is taller than 78% of dams nationwide.
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 | Hampshire |
| Nearest City | Williamsburg |
| River/Stream | Beaver Brook |
| Coordinates | 42.40024, -72.67130 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 33 ft |
| Dam Length | 1,300 ft |
| Year Completed | 1902 (124 years old) |
Storage & Hydraulics
| NID Storage | 761 acre-ft |
| Max Storage | 761 acre-ft |
| Normal Storage | 550 acre-ft |
| Surface Area | 20 acres |
| Drainage Area | 0 sq mi |
| Max Discharge | 560 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Northampton |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Last Inspection | 07/27/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00082 |
| Federal ID | MA00082 |
| More Info | State Dam Safety Program |