Crystal Lake Dam Reservoir Report

Last Updated: December 9, 2025

Crystal Lake Dam, located in Mountain Lakes Borough, New Jersey, is a local government-owned structure that serves primarily for recreation purposes.


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Summary

Situated on Troy Brook, this earth-type dam stands at a height of 16.3 feet with a length of 160 feet, providing a storage capacity of 118 acre-feet. Despite its small size, the dam has a high hazard potential, making regular inspections crucial to ensure its structural integrity.

The dam, regulated by the New Jersey Department of Environmental Protection, has a satisfactory condition assessment as of December 2020. With a significant surface area of 19 acres and a drainage area of 0.29 square miles, Crystal Lake Dam plays a vital role in water resource management in Morris County. However, its high hazard potential underscores the importance of maintaining and monitoring this structure to mitigate any potential risks and ensure public safety.

As a focal point for water resource and climate enthusiasts, Crystal Lake Dam offers a glimpse into the intersection of infrastructure, recreation, and environmental stewardship. With its picturesque location and recreational opportunities, this dam serves as both a functional water management asset and a popular destination for outdoor activities. Ongoing inspections and risk assessments are essential to safeguard the dam and the surrounding community from any potential hazards and uphold its role in sustaining the local ecosystem.

Dam Length

160

Dam Height

16.3

River Or Stream

Troy Brook

Primary Dam Type

Earth

Surface Area

19

Drainage Area

0.29

Nid Storage

118

Hazard Potential

High

Nid Height

16
       
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.