Stony Brook W.S. Site 11 (Amwell) Dam Reservoir Report

Last Updated: December 6, 2025

Stony Brook W.S.


°F

°F

mph

Wind

%

Humidity

Summary

Site 11 (Amwell) Dam, located in East Amwell Township, New Jersey, was completed in 1963 with a primary purpose of flood risk reduction along the Stony Brook-TR. This earth dam stands at a height of 22 feet and has a length of 951 feet, providing a storage capacity of 41 acre-feet and covering a surface area of 10 acres. The dam is owned and regulated by the state of New Jersey, specifically by the NJ Department of Environmental Protection (NJDEP), and is funded, designed, and constructed by the Natural Resources Conservation Service.

Despite being categorized as having a significant hazard potential, the condition assessment of Stony Brook W.S. Site 11 (Amwell) Dam is rated as fair, with the last inspection taking place in July 2020. The dam has an inspection frequency of 2 years and is in compliance with state permitting, inspection, and enforcement regulations. While there are no associated structures or locks, the dam serves as an essential infrastructure for flood risk mitigation in the region and is monitored closely to ensure public safety and environmental protection.

With Congressman Tom Malinowski representing the area in Congressional District 07, Stony Brook W.S. Site 11 (Amwell) Dam plays a crucial role in managing water resources and climate resilience in Hunterdon County, New Jersey. As a key component in the local watershed system, this dam serves as a vital tool in reducing flood risks and safeguarding the community against potential disasters. Keeping a close eye on its maintenance and structural integrity remains a top priority to ensure its continued effectiveness in protecting the surrounding area from water-related hazards.

Year Completed

1963

Dam Length

951

Dam Height

22

River Or Stream

Stony Brook-TR

Primary Dam Type

Earth

Surface Area

10

Drainage Area

0.93

Nid Storage

41

Hazard Potential

Significant

Nid Height

22
       
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.