Lake Arcadia Dam #1 Dam Reservoir Report

Last Updated: December 7, 2025

Located in West Milford Township, New Jersey, the Lake Arcadia Dam #1 Dam is a concrete structure completed in 1926 for the primary purpose of recreation.


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Summary

With a height of 22 feet and a length of 315 feet, the dam impounds Bear Swamp Brook, creating a surface area of 86 acres and a maximum storage capacity of 1,000 acre-feet. Despite its recreational value, the dam is classified as having a significant hazard potential and is currently in poor condition, as assessed in October 2021.

Owned privately, the dam falls under the regulatory jurisdiction of the New Jersey Department of Environmental Protection (NJDEP), which oversees its permitting, inspection, and enforcement. Although the dam has not been modified in recent years and lacks certain safety features such as an emergency action plan (EAP) and inundation maps, it is subject to regular inspections every two years to ensure its structural integrity and public safety. Given its condition assessment and hazard potential, the Lake Arcadia Dam #1 Dam serves as a critical reminder of the importance of maintaining and monitoring aging infrastructure in the face of evolving climate conditions.

As a key feature of the Passaic County landscape, the Lake Arcadia Dam #1 Dam poses both opportunities for recreation and potential risks in the event of a failure. With its historical significance dating back nearly a century, the dam serves as a testament to the engineering achievements of the past while highlighting the ongoing challenges of managing water resources and climate impacts in the present day. As water resource and climate enthusiasts continue to monitor the state of dams like Lake Arcadia Dam #1, they play a vital role in promoting resilience and sustainability in the face of a changing environment.

Year Completed

1926

Dam Length

315

Dam Height

22

River Or Stream

Bear Swamp Brook

Primary Dam Type

Concrete

Surface Area

86

Drainage Area

0.4

Nid Storage

1000

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.