Great Gorge Dam Reservoir Report

Last Updated: December 7, 2025

Great Gorge Dam in Vernon Township, New Jersey, stands as a vital structure for water supply purposes.


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Summary

Completed in 1971, this private-owned Earth dam holds a storage capacity of 290 acre-feet, with a maximum discharge of 25 cubic feet per second. Sitting on the Black River-TR, the dam spans 160 feet in length and stands at 28 feet in height, serving as a crucial resource for Sussex County.

With a high hazard potential, Great Gorge Dam has been deemed to be in satisfactory condition as of its last assessment in August 2020. The dam is regulated by the New Jersey Department of Environmental Protection, ensuring proper inspections, permitting, and enforcement. Its location in a picturesque setting in Sussex County highlights the importance of its function in providing water resources to the surrounding area.

Despite its significant role in water supply, Great Gorge Dam also poses risks that necessitate emergency action planning. While its condition is currently deemed acceptable, regular inspections and maintenance are essential to ensure the safety and reliability of this crucial infrastructure. As climate change continues to impact water resources, the management of dams like Great Gorge becomes increasingly important for sustainable water management and climate resilience efforts in the region.

Year Completed

1971

Dam Length

160

Dam Height

28

River Or Stream

Black River-TR

Primary Dam Type

Earth

Surface Area

23

Drainage Area

0.25

Nid Storage

290

Hazard Potential

High

Nid Height

28
       
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.