Lake Ames Dam Reservoir Report

Last Updated: December 9, 2025

Lake Ames Dam, located in Rockaway Township, Morris County, New Jersey, is a local government-owned structure that serves the primary purpose of recreation.


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Summary

Built in 1934, this earth dam stands at a height of 9 feet and spans a length of 320 feet, with a storage capacity of 128 acre-feet. Situated on the Hibernia Brook, the dam's normal storage level is 95 acre-feet, covering a surface area of 16 acres within a drainage area of 5.3 square miles.

Despite its recreational significance, Lake Ames Dam exhibits poor condition assessment and a significant hazard potential. The last inspection in November 2020 raised concerns about its structural integrity, prompting a biennial inspection frequency. The dam's emergency action plan (EAP) status is uncertain, with no recent updates on its preparedness or compliance with guidelines. Given its critical location and potential risks, it is crucial for the appropriate regulatory agencies, including the New Jersey Department of Environmental Protection (NJDEP), to ensure regular inspections, maintenance, and emergency response protocols for the safety of surrounding communities.

As an essential water resource within the region, Lake Ames Dam's management and maintenance require close attention and proactive measures to address its deteriorating condition and potential hazards. With the support of local and state authorities, including NJDEP, efforts should be made to enhance the dam's safety measures, conduct timely inspections, and update emergency response plans to mitigate risks and ensure the protection of the environment, infrastructure, and public safety in the area. By prioritizing the dam's rehabilitation and risk management strategies, stakeholders can safeguard this vital water infrastructure for future generations and uphold its recreational and ecological values amid changing climate conditions.

Year Completed

1934

Dam Length

320

Dam Height

9

River Or Stream

Hibernia Brook

Primary Dam Type

Earth

Surface Area

16

Drainage Area

5.3

Nid Storage

128

Hazard Potential

Significant

Nid Height

9
       
Seasonal Comparison

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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.