Lake Washington Dam Reservoir Report

Last Updated: December 6, 2025

Located in Haskell, New Jersey, the Lake Washington Dam is a key structure along the Wanaque River, serving as a recreational hotspot in Passaic County.


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Summary

Built in 1930, this earth and gravity dam stands at 11 feet tall and stretches 475 feet in length, with a storage capacity of 60 acre-feet. With a primary purpose of recreation, the dam offers a surface area of 8 acres for water enthusiasts to enjoy various activities.

Managed by the local government and regulated by the New Jersey Department of Environmental Protection, the Lake Washington Dam has a low hazard potential and is deemed to be in "Not Rated" condition as of the last inspection in September 2007. While the dam's emergency action plan and risk assessment status are currently undetermined, the structure's ability to handle a maximum discharge of 125 cubic feet per second underscores its importance in water resource management in the region. With its serene surroundings and ample storage capacity, the Lake Washington Dam continues to play a vital role in providing water-based recreational opportunities for residents and visitors alike.

As the centerpiece of Wanaque Borough, the Lake Washington Dam stands as a testament to the engineering prowess of its time and the enduring value of water resources in the community. With its rich history and functional design, this dam serves as a focal point for outdoor enjoyment and environmental stewardship, making it a must-visit destination for water resource and climate enthusiasts seeking to explore the intersection of human ingenuity and natural beauty in New Jersey's landscape.

Year Completed

1930

Dam Length

475

Dam Height

11

River Or Stream

Wanaque River

Primary Dam Type

Earth

Surface Area

8

Drainage Area

6.7

Nid Storage

60

Hazard Potential

Low

Nid Height

11
       
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.