Hanover Lake Dam Reservoir Report

Last Updated: December 8, 2025

Hanover Lake Dam, located in Browns Mills, New Jersey, is a Federal-owned structure managed by the US Air Force with a primary purpose of recreation.


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Summary

This Earth dam, completed in 1948, stands at a height of 9 feet and spans 400 feet in length, providing a storage capacity of 847 acre-feet. The dam controls the flow of the Hartshorne Mill Stream and has a significant hazard potential, with a moderate risk assessment rating.

Managed by the US Air Force, Hanover Lake Dam is subject to state regulation and inspection by the New Jersey Department of Environmental Protection. While the dam's condition assessment is not available, it has an established Emergency Action Plan last revised in 2014. The dam has a spillway type of Uncontrolled and a drainage area of 17 square miles, with a maximum discharge capacity of 840 cubic feet per second.

Water resource and climate enthusiasts interested in Hanover Lake Dam will find its historical significance, recreational purpose, and management by the US Air Force intriguing. With its moderate risk assessment and significant hazard potential, the dam plays a crucial role in controlling the water flow of the Hartshorne Mill Stream and ensuring public safety in the surrounding area of Pemberton, New Jersey.

Year Completed

1948

Dam Length

400

Dam Height

9

River Or Stream

HARTSHORNE MILL STREAM

Primary Dam Type

Earth

Surface Area

75

Drainage Area

17

Nid Storage

847

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

9
       
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.