Mine Hill Reservoir Dam Reservoir Report

Last Updated: December 7, 2025

Mine Hill Reservoir Dam, located in Hackettstown, New Jersey, stands as a vital structure in the region's water supply system.


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Summary

Completed in 1896, this concrete dam spans 310 feet in length and reaches a height of 30 feet, holding a maximum storage capacity of 35 acre-feet. The dam overlooks Mine Brook and serves as a key component in managing the area's surface water resources, with a normal storage capacity of 32 acre-feet spread over a surface area of 3 acres.

Despite its historical significance, Mine Hill Reservoir Dam's condition assessment reveals a poor rating, indicating a significant hazard potential. This assessment, last conducted in April 2019, highlights the urgent need for maintenance and potential rehabilitation efforts to ensure the dam's structural integrity and safety. The dam is regulated by the New Jersey Department of Environmental Protection (NJDEP), with regular inspections and enforcement measures in place to mitigate risks and safeguard the surrounding community.

As a private-owned structure, Mine Hill Reservoir Dam plays a crucial role in water resource management in Morris County, New Jersey. With its strategic location and historical importance, ongoing efforts are essential to address its poor condition assessment and significant hazard potential. Collaborative action between the dam's owners, regulatory agencies, and local stakeholders is imperative to secure the dam's long-term resilience and uphold its critical function in the region's water supply infrastructure.

Year Completed

1896

Dam Length

310

Dam Height

30

River Or Stream

Mine Brook

Primary Dam Type

Concrete

Surface Area

3

Drainage Area

1.8

Nid Storage

35

Hazard Potential

Significant

Nid Height

30
       
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.