Union Lake Dam Reservoir Report

Last Updated: December 5, 2025

Union Lake Dam, located in Millville, New Jersey, along the Maurice River, serves as a vital recreational resource for the community.


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Summary

Built in 1869, this earth dam stands at a height of 35 feet, with a length of 2000 feet, and a storage capacity of 20,100 acre-feet. The dam's primary purpose is for recreation, offering a surface area of 850 acres for boating, fishing, and other leisure activities.

Managed by the New Jersey Department of Environmental Protection (NJDEP), Union Lake Dam is state-regulated and undergoes regular inspections to ensure public safety. Despite its age, the dam is assessed to be in fair condition with a high hazard potential. This assessment prompts the implementation of risk management measures to safeguard the surrounding area in case of emergencies. With Congressman Jeff Van Drew representing the district, the dam plays a crucial role in water resource management and climate resilience efforts in the region.

As an integral part of the Cumberland County landscape, Union Lake Dam not only provides recreational opportunities but also serves as a key water management infrastructure. With its historical significance and ongoing maintenance efforts, the dam stands as a testament to the intersection of human development and environmental stewardship in the face of changing climate patterns. Moving forward, continued collaboration between state agencies, local stakeholders, and the community will be essential in ensuring the long-term sustainability and safety of Union Lake Dam for generations to come.

Year Completed

1869

Dam Length

2000

Dam Height

35

River Or Stream

Maurice River

Primary Dam Type

Earth

Surface Area

850

Drainage Area

218

Nid Storage

20100

Hazard Potential

High

Nid Height

35
       
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.