Ponaganset Reservoir
Ponaganset Reservoir is an earth dam located in Providence County, Rhode Island, built in 1865. It carries a High hazard potential classification and has a fair condition assessment.
About Ponaganset Reservoir
The primary purpose of Ponaganset Reservoir 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 Providence Water Supply Board/city Of Providence (local government). It impounds the Ponaganset River near Glocester.
The dam stands 26 feet tall and stretches 635 feet across, creates a reservoir covering 230 acres, has a maximum storage capacity of 3,657 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1865, the structure is one of the older dams in the region, with over a century and a half of service.
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. Notably, no emergency action plan is currently on file for this high-hazard dam.
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 Rhode Island 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 | Rhode Island |
| County | Providence |
| Nearest City | Glocester |
| River/Stream | Ponaganset River |
| Coordinates | 41.86777, -71.74194 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 26 ft |
| Dam Height | 25 ft |
| Dam Length | 635 ft |
| Year Completed | 1865 (161 years old) |
Storage & Hydraulics
| NID Storage | 3,657 acre-ft |
| Max Storage | 3,657 acre-ft |
| Normal Storage | 2,277 acre-ft |
| Surface Area | 230 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 130 cfs |
Ownership & Safety
| Purpose | Water Supply |
| Owner | PROVIDENCE WATER SUPPLY BOARD/CITY OF PROVIDENCE |
| Owner Type | Local Government |
| Hazard Classification | High |
| Condition Assessment | Fair |
| Emergency Action Plan | No |
Identifiers
| NID ID | RI01304 |
| Federal ID | RI01304 |
| More Info | State Dam Safety Program |