Lake Arrowhead Dam Reservoir Report

Last Updated: December 9, 2025

Lake Arrowhead Dam, located in Denville, New Jersey, is a privately owned earth dam completed in 1925 with a primary purpose of recreation.


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Summary

This dam on Den Brook stands at a height of 8 feet and has a length of 375 feet, creating a reservoir with a storage capacity of 114 acre-feet. The dam's surface area covers 19 acres, serving as a popular spot for outdoor activities and water-related recreation.

Managed by the New Jersey Department of Environmental Protection, Lake Arrowhead Dam is regularly inspected and has been deemed to be in satisfactory condition as of the last assessment in August 2021. The dam has a significant hazard potential due to its location and the surrounding area, but its safety measures and emergency action plan are up to date, ensuring prompt response in case of any unforeseen events. With its scenic setting and recreational opportunities, Lake Arrowhead Dam remains a vital water resource for the community while also being a key asset in climate resilience efforts in the region.

Congressional District 11's Representative Mikie Sherrill oversees this area, and the dam's condition is closely monitored to ensure public safety and environmental protection. As climate change continues to impact water resources, the importance of maintaining infrastructure like Lake Arrowhead Dam becomes increasingly crucial. Its role in providing recreational opportunities, water storage, and flood control highlights the significance of sustainable management practices for water resources amidst changing climatic conditions.

Year Completed

1925

Dam Length

375

Dam Height

8

River Or Stream

Den Brook

Primary Dam Type

Earth

Surface Area

19

Drainage Area

0.22

Nid Storage

114

Hazard Potential

Significant

Nid Height

8
       
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.