Hopkinton Reservoir Dam Reservoir Report

Last Updated: December 14, 2025

Hopkinton Reservoir Dam, located in Ashland, Massachusetts, was completed in 1891 and serves as a crucial water resource in the area.


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Summary

The dam, made of concrete with a height of 58 feet, creates a fish and wildlife pond that covers 213 acres and has a normal storage capacity of 4500 acre-feet. The reservoir is fed by Indian Brook and has a drainage area of 6.4 square miles, making it an important habitat for local wildlife.

Managed by the Department of Conservation and Recreation, the dam is regulated, permitted, inspected, and enforced by the state to ensure its safety and functionality. Despite being classified as having a high hazard potential, the dam's condition was assessed as satisfactory during its last inspection in June 2016. With a moderate risk assessment of 3, the dam has appropriate risk management measures in place to mitigate any potential issues.

Overall, Hopkinton Reservoir Dam is not only a vital water resource but also a recreational area for the community. With its historical significance and importance in wildlife conservation, the dam plays a crucial role in maintaining the ecological balance of the region. Climate and water resource enthusiasts will appreciate the efforts taken to ensure the safety and sustainability of this essential infrastructure.

Year Completed

1891

Dam Length

1616

Dam Height

58

River Or Stream

INDIAN BROOK

Primary Dam Type

Concrete

Surface Area

213

Hydraulic Height

51

Drainage Area

6.4

Nid Storage

6850

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

58
       
Seasonal Comparison

Weather Forecast

Dam Data Reference

Condition Assessment

Satisfactory
No 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

High
Dams 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.