Etra Mill Dam is an earth dam located in Mercer County, New Jersey, built in 1930. It carries a Low hazard potential classification.
Dam profile
NID height · 11 ft11 ft tall and 300 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 Etra Mill Dam
The primary purpose of Etra Mill Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Township of East Windsor (local government). It impounds the Rocky Brook near Hightstown.
The dam stands 11 feet tall and stretches 300 feet across, creates a reservoir covering 21 acres, has a storage capacity of 66 acre-feet, and collects water from a drainage area of 9 square miles. Completed in 1930, the structure is well-established, with more than 75 years of service.
This dam has a low hazard potential classification, meaning that failure would cause minimal damage, limited primarily to the dam owner's property, with no expected loss of life. The most recent inspection on record was 09/30/2004. That was over 22 years ago.
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Location
| State | New Jersey |
| County | Mercer |
| Nearest City | Hightstown |
| River/Stream | Rocky Brook |
| Coordinates | 40.25320, -74.50308 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 11 ft |
| Dam Height | 11 ft |
| Dam Length | 300 ft |
| Year Completed | 1930 (96 years old) |
Storage & Hydraulics
| NID Storage | 66 acre-ft |
| Normal Storage | 66 acre-ft |
| Surface Area | 21 acres |
| Drainage Area | 9 sq mi |
| Max Discharge | 380 cfs |
Ownership & Safety
| Purpose | Recreation |
| Owner | Township of East Windsor |
| Owner Type | Local Government |
| Hazard Classification | Low |
| Condition Assessment | Not assessed |
| Last Inspection | 09/30/2004 |
| Emergency Action Plan | Not Required |
Identifiers
| NID ID | NJ00298 |
| Federal ID | NJ00298 |
| More Info | State Dam Safety Program |