Ashby Reservoir Dam Reservoir Report
Last Updated: December 15, 2025
Ashby Reservoir Dam, located in Middlesex County, Massachusetts, was completed in 1918 and is primarily used for water supply purposes.
°F
°F
mph
Wind
%
Humidity
Summary
The dam stands at a height of 28 feet and has a hydraulic height of 18 feet, with a storage capacity of 294 acre-feet. The reservoir has a surface area of 41 acres and drains an area of 2.07 square miles, providing crucial water resources to the surrounding community.
Managed by the Department of Conservation and Recreation, the dam is regulated and inspected by the state of Massachusetts to ensure its structural integrity and safety. Despite being classified as having a significant hazard potential, the condition assessment of the dam is rated as fair. The last inspection of the dam was conducted in December 2013, with a scheduled frequency of every 5 years to monitor any potential risks or issues.
With an uncontrolled spillway type and no associated locks, Ashby Reservoir Dam poses a moderate risk level according to the data provided. The dam is situated on Willard Brook in the town of Ashby and plays a vital role in providing water supply for the region. Climate and water resource enthusiasts would find the engineering details and regulatory oversight of this concrete dam intriguing, highlighting the importance of maintaining and monitoring critical infrastructure for water management in the face of changing climate conditions.
Year Completed |
1918 |
Dam Length |
180 |
Dam Height |
28 |
River Or Stream |
WILLARD BROOK |
Primary Dam Type |
Concrete |
Surface Area |
41 |
Hydraulic Height |
18 |
Drainage Area |
2.07 |
Nid Storage |
294 |
Hazard Potential |
Significant |
Foundations |
Unlisted/Unknown |
Nid Height |
28 |
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.
Ashby Reservoir Dam