North Grosvenordale Dam
North Grosvenordale Dam is an earth dam located in Windham County, Connecticut, built in 1900. It carries a High hazard potential classification and has a poor condition assessment.
About North Grosvenordale Dam
The primary purpose of North Grosvenordale Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by 929 Riverside Drive Llc;windham North Properties Llc (private). It impounds the French River near North Grosvenordal.
The dam stands 25 feet tall and stretches 380 feet across, creates a reservoir covering 60 acres, has a maximum storage capacity of 840 acre-feet, and collects water from a drainage area of 99 square miles. Completed in 1900, 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 poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 11/30/2021.
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 | Windham |
| Nearest City | North Grosvenordal |
| River/Stream | French River |
| Coordinates | 41.99186, -71.89523 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 23 ft |
| Dam Length | 380 ft |
| Year Completed | 1900 (126 years old) |
Storage & Hydraulics
| NID Storage | 840 acre-ft |
| Max Storage | 840 acre-ft |
| Normal Storage | 540 acre-ft |
| Surface Area | 60 acres |
| Drainage Area | 99 sq mi |
| Max Discharge | 4,950 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | 929 Riverside Drive LLC;Windham North Properties LLC |
| Owner Type | Private |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 11/30/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | CT00183 |
| Federal ID | CT00183 |
| More Info | State Dam Safety Program |