Cocassett Lake Dam Reservoir Report
Nearby: Sunset Lake Dam Foundry Lake Dam
Last Updated: December 19, 2025
Cocassett Lake Dam, located in Foxborough, Massachusetts, is a privately owned structure that serves primarily for recreational purposes.
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Summary
Built in 1886, this earth dam on the Cocassett River stands at a height of 16 feet, with a hydraulic height of 13 feet and a length of 350 feet. The dam has a storage capacity of 215 acre-feet, with a normal storage level of 180 acre-feet and a surface area of 32 acres.
Despite its age, Cocassett Lake Dam is in fair condition and has a significant hazard potential, with a very high risk assessment rating. The dam is state-regulated by the Department of Conservation and Recreation and undergoes inspections every five years. The spillway type is controlled, and there are no locks associated with the dam. The dam's hazard potential and risk assessment highlight the importance of continued monitoring and maintenance to ensure its safety and longevity for both recreational use and water resource management in the area.
Year Completed |
1886 |
Dam Length |
350 |
Dam Height |
16 |
River Or Stream |
COCASSETT RIVER |
Primary Dam Type |
Earth |
Surface Area |
32 |
Hydraulic Height |
13 |
Drainage Area |
2.5 |
Nid Storage |
215 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
16 |
Seasonal Comparison
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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.
Cocassett Lake Dam
Beach Street Sharon