Cos Cob Pond Dam is an earth dam located in Fairfield County, Connecticut. It carries a Significant hazard potential classification and has a fair condition assessment.
Dam profile
NID height · 8 ft8 ft tall and 240 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 Cos Cob Pond Dam
The primary purpose of Cos Cob Pond Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Town of Greenwich (local government). It impounds the Brothers Brook near Greenwich.
The dam stands 8 feet tall and stretches 240 feet across, creates a reservoir covering 4 acres, has a maximum storage capacity of 40 acre-feet, and collects water from a drainage area of 1 square miles.
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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. The most recent inspection on record was 02/10/2022.
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Location
| State | Connecticut |
| County | Fairfield |
| Nearest City | Greenwich |
| River/Stream | Brothers Brook |
| Coordinates | 41.04885, -73.60084 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 8 ft |
| Dam Height | 8 ft |
| Dam Length | 240 ft |
Storage & Hydraulics
| NID Storage | 40 acre-ft |
| Max Storage | 40 acre-ft |
| Normal Storage | 20 acre-ft |
| Surface Area | 4 acres |
| Drainage Area | 1 sq mi |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Recreation |
| Owner | Town of Greenwich |
| Owner Type | Local Government |
| Hazard Classification | Significant |
| Condition Assessment | Fair |
| Last Inspection | 02/10/2022 |
| Emergency Action Plan | No |
Identifiers
| NID ID | CT00950 |
| Federal ID | CT00950 |
| More Info | State Dam Safety Program |