Valhalla Lake Dam Reservoir Report

Last Updated: December 10, 2025

Valhalla Lake Dam, located in Montville, New Jersey, was completed in 1910 for recreational purposes.


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Summary

This private earth and gravity dam stands at a height of 18 feet and has a length of 620 feet, creating a storage capacity of 1020 acre-feet. With a surface area of 85 acres and a drainage area of 2.37 square miles, the dam regulates the flow of the Morris Canal-TR river.

Despite its historical significance and recreational value, Valhalla Lake Dam poses a high hazard potential and has been assessed as being in poor condition. The last inspection in November 2019 highlighted the need for improved maintenance and monitoring to ensure the safety of the surrounding community. With a designated inspection frequency of every two years, it is crucial for stakeholders to address the dam's structural integrity and emergency preparedness.

As water resource and climate enthusiasts, the data on Valhalla Lake Dam serves as a reminder of the importance of proper dam management and maintenance in safeguarding communities and the environment. With the dam being regulated by the New Jersey Department of Environmental Protection and located in a high-risk area, proactive measures must be taken to mitigate potential hazards and ensure the long-term sustainability of this vital water resource infrastructure.

Year Completed

1910

Dam Length

620

Dam Height

18

River Or Stream

Morris Canal-TR

Primary Dam Type

Earth

Surface Area

85

Drainage Area

2.37

Nid Storage

1020

Hazard Potential

High

Nid Height

18
       
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.