Mayham Pond Dam Reservoir Report
Last Updated: December 6, 2025
Mayham Pond Dam, located in Grand Gorge, New York, is a stone dam completed in 1813 with a primary purpose of recreation.
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Summary
The dam stands at a height of 11 feet and has a length of 109 feet, creating a storage capacity of 224 acre-feet. It is situated on Bear Kill, within a drainage area of 3.87 square miles, and has a surface area of 37 acres. The dam is state regulated by the NYS DEC, with state permitting, inspection, and enforcement in place.
Despite being rated as having a low hazard potential and not having a current condition assessment, Mayham Pond Dam poses a moderate risk level (3) according to a risk assessment. The dam features an uncontrolled spillway with a width of 16 feet, and the last inspection was conducted in July 2015. While emergency action plans and inundation maps are not currently prepared, the dam meets state guidelines and has had emergency contacts updated. With its historical significance, recreational purpose, and moderate risk level, Mayham Pond Dam remains a focal point for water resource and climate enthusiasts in the area.
Year Completed |
1813 |
Dam Length |
109 |
Dam Height |
11 |
River Or Stream |
BEAR KILL |
Primary Dam Type |
Stone |
Surface Area |
37 |
Drainage Area |
3.87 |
Nid Storage |
224 |
Hazard Potential |
Low |
Nid Height |
11 |
Seasonal Comparison
Weather Forecast
Nearby Streamflow Levels
Dam Data Reference
Condition Assessment
SatisfactoryNo 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
HighDams 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.
Mayham Pond Dam