Glenn Lake Dam Reservoir Report

Last Updated: December 6, 2025

Glenn Lake Dam, also known as Glenn Lake Pond Dam, is a private structure located in Haynes, New York.


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Summary

Completed in 1965, this earth dam stands at a height of 43 feet and spans 722 feet in length, creating a storage capacity of 516 acre-feet for recreational purposes. Situated on Lyon Brook, the dam serves as a vital recreational resource for the local community, offering a surface area of 21 acres for various outdoor activities.

Managed by the NYS DEC, Glenn Lake Dam is subject to state regulations, inspections, and enforcement to ensure its safety and compliance. Despite its high hazard potential, the dam's condition assessment in 2019 deemed it satisfactory, with a moderate risk level. The spillway, with a width of 110 feet, is uncontrolled, allowing for a maximum discharge of 880 cubic feet per second. While the dam has not undergone any modifications in recent years, it continues to be monitored with an inspection frequency of every two years to maintain its structural integrity and safety.

With its picturesque surroundings and ample storage capacity, Glenn Lake Dam remains a significant water resource and recreational asset in Chenango County, New York. As a privately owned structure, it plays a crucial role in providing opportunities for outdoor recreation while adhering to state regulations and safety standards. As climate change impacts water resources, the maintenance and monitoring of dams like Glenn Lake Dam are essential to ensure the sustainability and safety of these vital infrastructure assets for future generations.

Year Completed

1965

Dam Length

722

Dam Height

43

River Or Stream

LYON BROOK

Primary Dam Type

Earth

Surface Area

21

Drainage Area

2.09

Nid Storage

516

Hazard Potential

High

Nid Height

43
       
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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.