Cambridge Reservoir Dam
Cambridge Reservoir Dam is an earth dam located in Middlesex County, Massachusetts, built in 1897. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Cambridge Reservoir Dam
The primary purpose of Cambridge 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 Cambridge (local government). It impounds the Hobbs Brook near Waltham.
The dam stands 31 feet tall and stretches 1,450 feet across, creates a reservoir covering 546 acres, has a maximum storage capacity of 10,380 acre-feet, and collects water from a drainage area of 6 square miles. Completed in 1897, 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 11/02/2022.
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 | Waltham |
| River/Stream | Hobbs Brook |
| Coordinates | 42.39864, -71.27312 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 31 ft |
| Dam Length | 1,450 ft |
| Year Completed | 1897 (129 years old) |
Storage & Hydraulics
| NID Storage | 10,380 acre-ft |
| Max Storage | 10,380 acre-ft |
| Normal Storage | 7,360 acre-ft |
| Surface Area | 546 acres |
| Drainage Area | 6 sq mi |
| Max Discharge | 744 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | City of Cambridge |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 11/02/2022 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | MA00750 |
| Federal ID | MA00750 |
| More Info | State Dam Safety Program |