Midvale Dam Reservoir Report

Last Updated: December 6, 2025

Midvale Dam, located in Wanaque Borough, New Jersey, is a state-regulated earth dam constructed in 1928 for the primary purpose of water supply on the Wanaque River.


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Summary

Standing at a height of 61 feet and stretching 290 feet in length, the dam has a normal storage capacity of 71,325 acre-feet within its 2400-acre surface area. Its hazard potential is classified as high, but its condition assessment as of October 2021 was deemed satisfactory.

The dam, owned by the state of New Jersey and regulated by the NJDEP, undergoes inspections every two years to ensure its structural integrity and safety. The surrounding area of Passaic County benefits from the water storage provided by Midvale Dam, supporting the region's water supply needs. Despite its age, the dam continues to fulfill its purpose efficiently and effectively, showcasing the importance of proper maintenance and regulation in water resource management and climate resilience efforts.

Midvale Dam serves as a vital infrastructure for water resource enthusiasts and climate advocates, highlighting the intersection of environmental conservation and infrastructure development. Its presence on the Wanaque River underscores the significance of sustainable water management practices in ensuring the resilience of communities and ecosystems against the impacts of climate change. As a key component of New Jersey's water supply infrastructure, Midvale Dam stands as a testament to the ongoing efforts to balance resource utilization with environmental protection in the face of evolving climate challenges.

Year Completed

1928

Dam Length

290

Dam Height

61

River Or Stream

Wanaque River

Primary Dam Type

Earth

Surface Area

2400

Drainage Area

90.4

Nid Storage

71325

Hazard Potential

High

Nid Height

61
       
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.