Mance Pond Dam Reservoir Report

Last Updated: December 6, 2025

Mance Pond Dam, also known as Alder Pond, is a privately owned earth dam located in Delaware County, New York.


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Summary

Completed in 1991, this recreational structure stands at a height of 12 feet and spans a length of 470 feet, with a storage capacity of 79 acre-feet. Situated on the TR-Tremper Kill river/stream, the dam's primary purpose is for recreation, offering a serene 9-acre surface area for water enthusiasts and nature lovers to enjoy.

Managed by the New York State Department of Environmental Conservation (NYS DEC), Mance Pond Dam is regulated, permitted, inspected, and enforced to ensure its safety and compliance with state guidelines. Despite its low hazard potential and moderate risk assessment, the dam's condition remains unrated as of the last inspection in April 2006. With an uncontrolled spillway width of 76 feet, the dam continues to provide a tranquil and secure environment for visitors seeking outdoor recreational activities in the heart of New York's picturesque countryside.

For water resource and climate enthusiasts, Mance Pond Dam stands as a testament to the harmonious balance between human recreation and environmental stewardship. With its modest size and careful management, this earth dam serves as a sustainable oasis for those seeking solace in nature while upholding the importance of responsible dam operation and maintenance. As climate change continues to impact water resources, Mance Pond Dam exemplifies the resilience and adaptability needed to preserve our natural landscapes for future generations to enjoy.

Year Completed

1991

Dam Length

470

Dam Height

12

River Or Stream

TR-TREMPER KILL

Primary Dam Type

Earth

Surface Area

9

Drainage Area

0.51

Nid Storage

79

Hazard Potential

Low

Nid Height

12
       
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.