Mary Elmer Lake Dam Reservoir Report

Last Updated: December 5, 2025

Mary Elmer Lake Dam, located in Bridgeton City, Cumberland County, New Jersey, is a significant earth dam completed in 1924 for recreational purposes.


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Summary

This local government-owned structure on the Cohansey River is regulated by the New Jersey Department of Environmental Protection, ensuring regular inspections, permitting, and enforcement to maintain its satisfactory condition. With a height of 15 feet and a length of 500 feet, the dam holds a storage capacity of 68 acre-feet and covers a surface area of 22 acres.

Despite its age, Mary Elmer Lake Dam poses a significant hazard potential due to its size and location, making emergency preparedness crucial. The dam's condition assessment in 2021 deemed it satisfactory, but a comprehensive risk assessment and management plan may be necessary to mitigate potential threats. The dam's inspection frequency of every two years ensures ongoing monitoring, with the last inspection conducted in March 2021. The dam does not fall under the jurisdiction of the US Army Corps of Engineers.

Enthusiasts of water resources and climate in New Jersey can appreciate Mary Elmer Lake Dam as a vital recreational and water management structure on the Cohansey River. Its historical significance, regulatory oversight, and potential hazards underscore the importance of maintaining and managing this earth dam to ensure the safety of surrounding communities and the preservation of the local environment.

Year Completed

1924

Dam Length

500

Dam Height

15

River Or Stream

Cohansey River

Primary Dam Type

Earth

Surface Area

22

Drainage Area

7.5

Nid Storage

68

Hazard Potential

Significant

Nid Height

15
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.