Mallory Pond Dam Reservoir Report

Last Updated: December 6, 2025

Mallory Pond Dam, located in Black Lake, Sullivan County, New York, is a private earth dam primarily used for recreational purposes.


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Summary

Completed in 1950, the dam stands at 7 feet high and stretches for 310 feet, with a storage capacity of 90 acre-feet. The dam impounds Mallory Brook, creating a surface area of 38 acres for recreational activities such as fishing and boating.

Despite being classified as having a low hazard potential, Mallory Pond Dam is regulated by the New York State Department of Environmental Conservation (NYS DEC) and undergoes regular inspections, permitting, and enforcement to ensure its safety and compliance with state regulations. The dam's spillway, with a width of 17 feet, is uncontrolled, allowing for controlled release of water during periods of high flow. The risk assessment for the dam is moderate, indicating a level 3 risk rating.

While Mallory Pond Dam has not been rated for its condition, it is important for water resource and climate enthusiasts to monitor its maintenance and management to prevent potential risks. With a history dating back to the early 20th century, this dam serves as a vital recreational resource in the region, highlighting the importance of sustainable dam operations and safety measures to protect both the environment and the community.

Year Completed

1950

Dam Length

310

Dam Height

7

River Or Stream

MALLORY BROOK

Primary Dam Type

Earth

Surface Area

38

Nid Storage

90

Hazard Potential

Low

Nid Height

7
       
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.