Lake Ashroe Dam Reservoir Report

Last Updated: December 13, 2025

Lake Ashroe Dam, located in Sussex, New Jersey, is a state-owned structure primarily used for recreation purposes.


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Summary

Built in 1972, this earth dam stands at a height of 19 feet and has a storage capacity of 697 acre-feet, providing ample water resources for the area. With a surface area of 42 acres and a drainage area of 1.2 square miles, the dam plays a significant role in managing water flow and storage in the region.

Managed by the New Jersey Department of Environmental Protection (NJDEP), Lake Ashroe Dam is subject to regular state inspections, ensuring its structural integrity and safety. The dam has a significant hazard potential, but its condition assessment in 2020 deemed it satisfactory. In case of emergencies, an Emergency Action Plan (EAP) may be in place, although details on its preparation and guidelines adherence are not currently available. The dam's location on Big Flat Brook-TR and its proximity to Sandyston Township make it a key water resource for the surrounding area.

For water resource and climate enthusiasts, Lake Ashroe Dam presents a fascinating case study in dam management and regulation. Its construction by the Natural Resources Conservation Service and oversight by state agencies highlight the importance of maintaining infrastructure for both recreational and water storage purposes. The dam's role in controlling water flow, its storage capacity, and its potential risks underscore the critical need for continuous monitoring and maintenance to ensure the safety and sustainability of this essential water resource in New Jersey.

Year Completed

1972

Dam Length

220

Dam Height

19

River Or Stream

Big Flat Brook-TR

Primary Dam Type

Earth

Surface Area

42

Drainage Area

1.2

Nid Storage

697

Hazard Potential

Significant

Nid Height

19
       
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.