Mallory Dam Reservoir Report

Last Updated: December 6, 2025

Mallory Dam, located in Mallory, New York, along Dykeman Creek, is a significant concrete dam completed in 1909 primarily for recreational purposes.


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Summary

With a height of 6 feet and a length of 352 feet, the dam provides a maximum storage capacity of 18 acre-feet, making it an essential water resource in the area. Despite its age, the dam is regularly inspected by the New York State Department of Environmental Conservation to ensure its structural integrity and compliance with safety regulations.

The dam's spillway is uncontrolled and has a width of 25 feet, further enhancing its ability to manage water flow during periods of high discharge. Classified with a significant hazard potential, Mallory Dam is deemed to have a moderate risk level, necessitating ongoing risk management measures to mitigate any potential threats to the surrounding area. Although the dam's condition is currently not rated, its emergency action plan was last revised in 2014, indicating a commitment to preparedness and safety measures in case of any unforeseen events.

Managed by a private entity, Mallory Dam stands as a vital infrastructure for both water resource management and recreational activities in Oswego County. Its strategic location and role in regulating water flow underscore its importance in ensuring a sustainable environment for both wildlife and residents in the region.

Year Completed

1909

Dam Length

352

Dam Height

6

River Or Stream

DYKEMAN CREEK

Primary Dam Type

Concrete

Surface Area

9

Nid Storage

18

Hazard Potential

Significant

Nid Height

6
       
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.