Portland Reservoir Dam
Portland Reservoir Dam is an earth dam located in Middlesex County, Connecticut, built in 1964. It carries a High hazard potential classification and has a satisfactory condition assessment.
About Portland Reservoir Dam
The primary purpose of Portland 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 Town Of Portland (local government). It impounds the Reservoir Brook near Portland.
The dam stands 28 feet tall and stretches 800 feet across, creates a reservoir covering 30 acres, has a maximum storage capacity of 510 acre-feet, and collects water from a drainage area of 3 square miles. Completed in 1964, the structure is well into its service life at over 50 years 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 10/10/2024.
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 Connecticut 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 | Connecticut |
| County | Middlesex |
| Nearest City | Portland |
| River/Stream | Reservoir Brook |
| Coordinates | 41.61522, -72.57018 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 28 ft |
| Dam Height | 28 ft |
| Dam Length | 800 ft |
| Year Completed | 1964 (62 years old) |
Storage & Hydraulics
| NID Storage | 510 acre-ft |
| Max Storage | 510 acre-ft |
| Normal Storage | 375 acre-ft |
| Surface Area | 30 acres |
| Drainage Area | 3 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Water Supply |
| Owner | Town of Portland |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 10/10/2024 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00149 |
| Federal ID | CT00149 |
| More Info | State Dam Safety Program |