Moose Pac Lake Dam Reservoir Report

Last Updated: December 9, 2025

Moose Pac Lake Dam, located in Jefferson Township, Morris County, New Jersey, stands as a significant earth dam constructed in 1918 primarily for recreational purposes.


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Summary

With a height of 10 feet and a length of 75 feet, the dam holds a normal storage capacity of 165 acre-feet and covers a surface area of 22 acres. It impounds the East Branch Rockaway River and is regulated by the New Jersey Department of Environmental Protection.

Despite its historical significance and recreational value, Moose Pac Lake Dam is rated as having a poor condition assessment with a significant hazard potential. The last inspection in January 2021 raised concerns about its structural integrity and safety measures. While the dam has an emergency action plan in place, there are ongoing efforts to address its risk management measures and ensure compliance with regulatory guidelines to mitigate potential hazards.

For water resource and climate enthusiasts, the Moose Pac Lake Dam serves as a focal point for understanding the importance of dam safety and maintenance in balancing recreational benefits with public safety. Efforts are underway to address the dam's poor condition assessment and enhance its risk management measures to ensure the protection of downstream communities and the ecological health of the East Branch Rockaway River. Stay tuned for updates on the conservation and rehabilitation efforts surrounding this iconic New Jersey landmark.

Year Completed

1918

Dam Length

75

Dam Height

10

River Or Stream

East Branch Rockaway River

Primary Dam Type

Earth

Surface Area

22

Drainage Area

0.4

Nid Storage

165

Hazard Potential

Significant

Nid Height

10
       
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.