Jefferson Lake Dam Reservoir Report

Last Updated: December 7, 2025

Jefferson Lake Dam, located in Sussex, New Jersey, is a state-regulated earth dam primarily used for recreation purposes.


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Summary

With a height of 15 feet and a length of 450 feet, the dam provides a storage capacity of 250 acre-feet and covers a surface area of 50 acres. Situated on Lubbers Run-TR, the dam is under the jurisdiction of the New Jersey Department of Environmental Protection (NJDEP) and has been inspected for safety and regulatory compliance.

Despite its low hazard potential, Jefferson Lake Dam has been assessed as being in poor condition as of 2005. The dam has not undergone any modifications or improvements since its completion, raising concerns about its structural integrity and long-term viability. Additionally, there is no Emergency Action Plan (EAP) in place, indicating a potential lack of preparedness for emergency situations related to the dam.

As a significant recreational resource in Byram Township, Jefferson Lake Dam plays a crucial role in providing water-based activities for the community. However, the dam's poor condition and lack of risk management measures highlight the need for proactive maintenance and safety planning to ensure the continued safety and sustainability of this valuable water resource.

Dam Length

450

Dam Height

15

River Or Stream

Lubbers Run-TR

Primary Dam Type

Earth

Surface Area

50

Drainage Area

5

Nid Storage

250

Hazard Potential

Low

Nid Height

15
       
Seasonal Comparison

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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.