Ellsworth (Detention Pond) Dam Reservoir Report

Last Updated: December 6, 2025

Ellsworth (Detention Pond) Dam, located in Somerset, New Jersey, serves as a vital flood risk reduction structure along the North Branch Raritan River.


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Summary

This private earth dam stands at a height of 9.3 feet and has a length of 400 feet, providing a storage capacity of 20 acre-feet. With a significant hazard potential, the dam is regularly inspected by the New Jersey Department of Environmental Protection to ensure its satisfactory condition and readiness for emergency situations.

The dam's primary purpose is flood risk reduction, serving as a crucial infrastructure in protecting the surrounding area from potential inundation during heavy rainfall or storm events. Despite its relatively small surface area of only 1 acre, the dam plays a critical role in mitigating flood impacts and ensuring the safety of the community in Bedminster Township. Managed by private owners, the Ellsworth Dam is subject to state regulations, inspections, and enforcement to uphold its structural integrity and operational effectiveness.

In the event of an emergency, the dam is equipped with an Emergency Action Plan (EAP) to guide response efforts and ensure public safety. With a designated inspection frequency and a satisfactory condition assessment, the Ellsworth (Detention Pond) Dam stands as a resilient barrier against flooding and a testament to effective water resource management in New Jersey's water infrastructure landscape.

Dam Length

400

Dam Height

9.3

River Or Stream

N. Branch Raratin River-TR

Primary Dam Type

Earth

Surface Area

1

Drainage Area

0.13

Nid Storage

20

Hazard Potential

Significant

Nid Height

9
       
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.