Cobbs Mill Dam Reservoir Report
Nearby: Thundergut Pond Dam Coxhat Pond Dam
Last Updated: December 5, 2025
Cobbs Mill Dam, located in Alloway Township, New Jersey, is a privately owned structure built in 1940 primarily for recreational purposes along the Deep Run river.
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Summary
This earth dam stands at a height of 9.5 feet and has a length of 275 feet, creating a reservoir with a normal storage capacity of 29 acre-feet. Despite its age, the dam is in poor condition with a significant hazard potential, as indicated by the last inspection in March 2020.
Managed by the New Jersey Department of Environmental Protection, Cobbs Mill Dam is subject to state regulation, permitting, inspection, and enforcement. The dam poses a potential risk to surrounding areas in the event of a structural failure, highlighting the importance of ongoing maintenance and risk management measures. With a condition assessment rating of poor, there is a clear need for attention and potential upgrades to ensure the safety and integrity of this recreational structure for water resource and climate enthusiasts who frequent the area.
As climate change continues to impact water resources and infrastructure, the significance of maintaining and assessing dams like Cobbs Mill becomes increasingly critical. With its location in a congressional district represented by Jeff Van Drew, the dam's condition and potential risks should be closely monitored and addressed to mitigate any potential threats to the community and environment. As enthusiasts of water resources and climate resilience, staying informed and engaged in the safety and upkeep of structures like Cobbs Mill Dam is vital for ensuring the long-term sustainability of our water systems.
Year Completed |
1940 |
Dam Length |
275 |
Dam Height |
9.5 |
River Or Stream |
Deep Run |
Primary Dam Type |
Earth |
Surface Area |
14 |
Drainage Area |
1.8 |
Nid Storage |
29 |
Hazard Potential |
Significant |
Nid Height |
10 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo existing or potential dam safety deficiencies are recognized. Acceptable performance is expected under all loading conditions (static, hydrologic, seismic) in accordance with the minimum applicable state or federal regulatory criteria or tolerable risk guidelines.
Fair
No existing dam safety deficiencies are recognized for normal operating conditions. Rare or extreme hydrologic and/or seismic events may result in a dam safety deficiency. Risk may be in the range to take further action. Note: Rare or extreme event is defined by the regulatory agency based on their minimum
Poor A dam safety deficiency is recognized for normal operating conditions which may realistically occur. Remedial action is necessary. POOR may also be used when uncertainties exist as to critical analysis parameters which identify a potential dam safety deficiency. Investigations and studies are necessary.
Unsatisfactory
A dam safety deficiency is recognized that requires immediate or emergency remedial action for problem resolution.
Not Rated
The dam has not been inspected, is not under state or federal jurisdiction, or has been inspected but, for whatever reason, has not been rated.
Not Available
Dams for which the condition assessment is restricted to approved government users.
Hazard Potential Classification
HighDams assigned the high hazard potential classification are those where failure or mis-operation will probably cause loss of human life.
Significant
Dams assigned the significant hazard potential classification are those dams where failure or mis-operation results in no probable loss of human life but can cause economic loss, environment damage, disruption of lifeline facilities, or impact other concerns. Significant hazard potential classification dams are often located in predominantly rural or agricultural areas but could be in areas with population and significant infrastructure.
Low
Dams assigned the low hazard potential classification are those where failure or mis-operation results in no probable loss of human life and low economic and/or environmental losses. Losses are principally limited to the owner's property.
Undetermined
Dams for which a downstream hazard potential has not been designated or is not provided.
Not Available
Dams for which the downstream hazard potential is restricted to approved government users.
Cobbs Mill Dam
Piney Point Trail Cumberland County