Nabnasset Pond Dam Reservoir Report
Nearby: Stony Brook Dam Brookside Mill Dam
Last Updated: December 17, 2025
Nabnasset Pond Dam, located in Westford, Massachusetts, is a significant earth dam built in 1926 for the primary purpose of recreation.
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Summary
The dam, situated on a tributary of Stony Brook, stands at a height of 14 feet with a hydraulic height of 11 feet, creating a reservoir with a storage capacity of 1500 acre-feet. With a surface area of 140 acres and a drainage area of 1.73 square miles, the dam serves as a popular recreational spot for water enthusiasts in the Middlesex County area.
Managed by the Department of Conservation and Recreation, the dam is regulated by the state and undergoes regular inspections to ensure its structural integrity. The condition assessment of the dam is rated as fair, with a significant hazard potential. In case of emergencies, the dam is equipped with emergency action plans to ensure safety measures are in place. Despite being at moderate risk, the dam continues to be a valuable asset for water resource and climate enthusiasts in the region.
For those interested in water resource management and climate conservation, Nabnasset Pond Dam serves as a prime example of how dams can be utilized for recreational purposes while also being subject to strict regulatory measures to ensure public safety. As a focal point for outdoor activities in the area, the dam stands as a testament to the careful balance between environmental preservation and human enjoyment of natural resources. Its significance in both water management and recreational activities makes it a noteworthy site for enthusiasts looking to explore the intersection of water resources and climate conservation.
Year Completed |
1926 |
Dam Length |
200 |
Dam Height |
14 |
River Or Stream |
TRIBUTARY OF STONY BROOK |
Primary Dam Type |
Earth |
Surface Area |
140 |
Hydraulic Height |
11 |
Drainage Area |
1.73 |
Nid Storage |
1500 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
14 |
Seasonal Comparison
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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.
Nabnasset Pond Dam
Pawtucket Boulevard 936-970, Lowell