Mavis Pond #1 Dam is an earth dam located in Windham County, Connecticut, built in 1870. It carries a Significant hazard potential classification.
Dam profile
NID height · 13 ft13 ft tall and 172 ft long. Height is drawn to scale against a two-story house, about 25 ft; the profile is a generic embankment section and the water level is illustrative.
About Mavis Pond #1 Dam
The primary purpose of Mavis Pond #1 Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Sandra L. Warner & Frank R. Hallett (private). It impounds the Fivemile River near Thompson.
The dam stands 13 feet tall and stretches 172 feet across, creates a reservoir covering 12 acres, has a maximum storage capacity of 65 acre-feet, and collects water from a drainage area of 2 square miles. Completed in 1870, the structure is one of the older dams in the region, with over a century and a half of service.
This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life.
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Location
| State | Connecticut |
| County | Windham |
| Nearest City | Thompson |
| River/Stream | Fivemile River |
| Coordinates | 42.00530, -71.81541 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 13 ft |
| Dam Height | 13 ft |
| Dam Length | 172 ft |
| Year Completed | 1870 (156 years old) |
Storage & Hydraulics
| NID Storage | 65 acre-ft |
| Max Storage | 65 acre-ft |
| Normal Storage | 65 acre-ft |
| Surface Area | 12 acres |
| Drainage Area | 2 sq mi |
| Max Discharge | 32 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Sandra L. Warner & Frank R. Hallett |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Not assessed |
| Emergency Action Plan | No |
Identifiers
| NID ID | CT00188 |
| Federal ID | CT00188 |
| More Info | State Dam Safety Program |