Mountain Lake Dam Reservoir Report
Nearby: Wasserlauf Dam Black Lake Dam
Last Updated: December 7, 2025
Mountain Lake Dam is a privately owned structure located in Smallwood, Sullivan County, New York.
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Summary
Built in 1928, this earth dam stands at a height of 10 feet and stretches 200 feet in length, creating a reservoir with a storage capacity of 394 acre-feet. The dam serves primarily for recreational purposes, providing a serene setting for activities such as fishing, boating, and picnicking.
Managed by the New York State Department of Environmental Conservation, the Mountain Lake Dam is regulated, inspected, and enforced to ensure its safety and functionality. With a low hazard potential and a very high risk assessment rating, measures are in place to mitigate any potential risks associated with the dam. The controlled spillway and a maximum discharge capacity of 30 cubic feet per second help manage water levels and prevent flooding downstream.
Enthusiasts of water resources and climate will appreciate the significance of Mountain Lake Dam in supporting both recreational activities and water supply needs in the area. With its picturesque location and vital role in water management, this dam serves as a testament to the importance of sustainable infrastructure for both human enjoyment and environmental preservation in the region.
Year Completed |
1928 |
Dam Length |
200 |
Dam Height |
10 |
River Or Stream |
WHITE LAKE BROOK |
Primary Dam Type |
Earth |
Surface Area |
64 |
Drainage Area |
8.59 |
Nid Storage |
394 |
Hazard Potential |
Low |
Nid Height |
10 |
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.
Mountain Lake Dam