Johnson Millpond Dam is an earth dam located in Middlesex County, Connecticut, built in 1880. It carries a Significant hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 25 ft25 ft tall and 414 ft long, taller than 50% of U.S. dams with a recorded height. 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 Johnson Millpond Dam
The primary purpose of Johnson Millpond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Rajon Realty Corporation (private). It impounds the Moodus River near East Haddam.
The dam stands 25 feet tall and stretches 414 feet across, creates a reservoir covering 13 acres, has a maximum storage capacity of 143 acre-feet, and collects water from a drainage area of 15 square miles. Completed in 1880, the structure is over a century old.
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. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 04/28/2022.
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Location
| State | Connecticut |
| County | Middlesex |
| Nearest City | East Haddam |
| River/Stream | Moodus River |
| Coordinates | 41.49423, -72.46606 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 25 ft |
| Dam Height | 25 ft |
| Dam Length | 414.5 ft |
| Year Completed | 1880 (146 years old) |
Storage & Hydraulics
| NID Storage | 143 acre-ft |
| Max Storage | 143 acre-ft |
| Normal Storage | 143 acre-ft |
| Surface Area | 13 acres |
| Drainage Area | 15 sq mi |
| Max Discharge | 2,544 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Rajon Realty Corporation |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Satisfactory |
| Last Inspection | 04/28/2022 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CT00353 |
| Federal ID | CT00353 |
| More Info | State Dam Safety Program |