Lower Mill Pond Or Stoney Brook Dam Reservoir Report
Last Updated: December 21, 2025
The Lower Mill Pond or Stoney Brook Dam in Brewster, Massachusetts, is a vital water resource managed by the local government for recreational purposes.
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Summary
Built in 1920, this earth dam stands at a height of 6.5 feet and has a hydraulic height of 5.1 feet, providing storage of 690 acre-feet with a normal storage capacity of 250 acre-feet. The dam is located on the Stony Brook River and covers a surface area of 51 acres within a drainage area of 4.7 square miles.
Managed by the Department of Conservation and Recreation, the dam is state-regulated and undergoes regular inspections to ensure its safety and structural integrity. With a low hazard potential and a satisfactory condition assessment, the dam poses a moderate risk according to the risk assessment rating. The emergency action plan is in place, and the dam meets regulatory guidelines for its operation and maintenance.
Enthusiasts of water resources and climate will appreciate the significance of the Lower Mill Pond or Stoney Brook Dam as a recreational area while recognizing the importance of its management and regulatory oversight. This earth dam serves not only as a storage facility but also as a safety measure for the surrounding area. With its historical background, structural details, and risk assessment information, the dam stands as a symbol of responsible water resource management in Barnstable County, Massachusetts.
Year Completed |
1920 |
Dam Height |
6.5 |
River Or Stream |
STONY BROOK |
Primary Dam Type |
Earth |
Surface Area |
51 |
Hydraulic Height |
5.1 |
Drainage Area |
4.7 |
Nid Storage |
690 |
Hazard Potential |
Low |
Foundations |
Unlisted/Unknown |
Nid Height |
7 |
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.
Lower Mill Pond Or Stoney Brook Dam
Slough Road 159-265, Brewster