Assunpink #4 Dam Reservoir Report

Last Updated: December 7, 2025

Assunpink #4 Dam, located in Upper Freehold Township, New Jersey, is a state-owned structure designed for flood risk reduction along Assunpink Creek.


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Summary

The dam, primarily made of earth and gravity components, stands at a height of 24.2 feet and spans a length of 2900 feet. With a storage capacity of 4300 acre-feet, the dam serves multiple purposes including flood risk reduction, fish and wildlife pond creation, and recreation.

Despite its essential role in managing water resources and mitigating flooding in the area, Assunpink #4 Dam has been classified with a high hazard potential and poor condition assessment. The last inspection in July 2021 highlighted the need for improvements and maintenance to ensure the structure's continued effectiveness and safety. The dam falls under the jurisdiction of the New Jersey Department of Environmental Protection and is subject to state regulation, permitting, inspection, and enforcement.

As water resource and climate enthusiasts monitor the status of Assunpink #4 Dam, there is a growing emphasis on the importance of maintaining and upgrading infrastructure to enhance resilience to climate change impacts and safeguard communities and ecosystems. With its critical role in flood risk reduction and ecosystem management, the dam serves as a focal point for ongoing efforts to balance water resource management, environmental conservation, and public safety in the region.

Dam Length

2900

Dam Height

24.2

River Or Stream

Assunpink Creek

Primary Dam Type

Earth

Surface Area

225

Drainage Area

6.3

Nid Storage

4300

Hazard Potential

High

Nid Height

24
       
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.