Harrison Mountain Lake Dam Reservoir Report

Last Updated: December 6, 2025

Harrison Mountain Lake Dam in Ringwood Borough, New Jersey, is a privately owned structure with a primary purpose of recreation.


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Summary

Completed in 1930, this Earth-type dam stands at a height of 15 feet and has a length of 470 feet, creating a reservoir with a normal storage capacity of 76 acre-feet. Situated on Branch Brunt Meadow Brook in Passaic County, the dam boasts a surface area of 12 acres and serves as a popular spot for outdoor activities such as fishing, boating, and picnicking.

Managed by the New Jersey Department of Environmental Protection, Harrison Mountain Lake Dam is classified as a low hazard potential structure with its last inspection conducted in November 2001. While its condition assessment is currently listed as "Not Rated," the dam is subject to state regulation, permitting, inspection, and enforcement to ensure its safety and compliance with regulatory standards. With its tranquil surroundings and recreational opportunities, this dam is a valuable resource for water enthusiasts and climate advocates seeking to enjoy and protect New Jersey's natural landscapes.

Located in Congressional District 05, the Harrison Mountain Lake Dam is part of the Philadelphia District of the US Army Corps of Engineers. Despite not being a USACE-owned structure, the dam's design and construction are overseen by state agencies to uphold safety standards and mitigate potential risks. As a significant feature in the local landscape, this dam serves as a reminder of the importance of responsible water resource management and environmental stewardship in the face of changing climate conditions.

Year Completed

1930

Dam Length

470

Dam Height

15

River Or Stream

Branch Brunt Meadow Brook

Primary Dam Type

Earth

Surface Area

12

Drainage Area

0.21

Nid Storage

76

Hazard Potential

Low

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.