Monksville Dam Reservoir Report
Last Updated: December 6, 2025
Monksville Dam, located in Ringwood Borough, New Jersey, is a state-regulated structure on the Wanaque River with a primary purpose of water supply.
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Summary
Standing at a height of 150 feet and completed in 1986, the dam boasts a storage capacity of 27,500 acre-feet and a drainage area of 42.9 square miles. With a maximum discharge rate of 21,684 cubic feet per second, the dam plays a crucial role in managing water resources in the region.
Despite its satisfactory condition assessment as of October 2021, Monksville Dam poses a high hazard potential, highlighting the importance of regular inspections and maintenance to ensure its continued safety and functionality. The dam's emergency action plan (EAP) status and risk management measures are currently unclear, underscoring the need for ongoing monitoring and preparedness in the face of potential emergencies. As a key component of the water infrastructure in Passaic County, Monksville Dam serves as a vital resource for water supply and flood control, emphasizing the significance of its proper management and maintenance for the community and the environment.
As a state-owned structure overseen by the New Jersey Department of Environmental Protection (NJDEP), Monksville Dam plays a crucial role in water resource management in the region. With its significant storage capacity and high hazard potential, the dam underscores the importance of proactive risk assessment, emergency preparedness, and ongoing maintenance to ensure the safety and reliability of the water supply system. Climate and water resource enthusiasts alike can appreciate the intricate balance of engineering, regulation, and environmental stewardship that goes into managing a vital infrastructure like Monksville Dam in the context of our changing climate and growing water needs.
Year Completed |
1986 |
Dam Length |
2170 |
Dam Height |
150 |
River Or Stream |
Wanaque River |
Primary Dam Type |
Other |
Surface Area |
533 |
Drainage Area |
42.9 |
Nid Storage |
27500 |
Hazard Potential |
High |
Nid Height |
150 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Monksville Dam
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