Cobbs Mill Dam
Cobbs Mill Dam is an earth dam located in Salem County, New Jersey, built in 1940. It carries a Significant hazard potential classification and has a poor condition assessment.
About Cobbs Mill Dam
The primary purpose of Cobbs Mill Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by William R. Cobb (private). It impounds the Deep Run near Alloway.
The dam stands 10 feet tall and stretches 275 feet across, creates a reservoir covering 14 acres, has a storage capacity of 29 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1940, the structure is well-established, with more than 75 years 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. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. The most recent inspection on record was 03/24/2020.
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Location
| State | New Jersey |
| County | Salem |
| Nearest City | Alloway |
| River/Stream | Deep Run |
| Coordinates | 39.52862, -75.32145 |
Physical Characteristics
| Dam Type | Earth |
| NID Height | 10 ft |
| Dam Height | 10 ft |
| Dam Length | 275 ft |
| Year Completed | 1940 (86 years old) |
Storage & Hydraulics
| NID Storage | 29 acre-ft |
| Normal Storage | 29 acre-ft |
| Surface Area | 14 acres |
| Drainage Area | 1 sq mi |
Ownership & Safety
| Purpose | Recreation |
| Owner | William R. Cobb |
| Owner Type | Private |
| Hazard Classification | Significant |
| Condition Assessment | Poor |
| Last Inspection | 03/24/2020 |
| Emergency Action Plan | No |
Identifiers
| NID ID | NJ00612 |
| Federal ID | NJ00612 |
| More Info | State Dam Safety Program |