Coes Reservoir Dam Reservoir Report

Last Updated: December 12, 2025

Coes Reservoir Dam, located in Worcester, Massachusetts, stands as a vital recreational resource for the local community.


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Summary

Completed in 1865, this earth dam boasts a height of 21 feet and a length of 600 feet, creating a reservoir with a storage capacity of 1,223 acre-feet. While primarily serving recreational purposes, the dam also contributes to flood control and water resource management in the area.

Managed by the Department of Conservation and Recreation, the dam is regulated by the state of Massachusetts and undergoes regular inspections to ensure its structural integrity and safety. With a hazard potential classified as high and a condition assessment rated as fair, the dam remains a crucial component of the local infrastructure. In the event of an emergency, the dam's Emergency Action Plan is designed to meet guidelines and facilitate prompt response.

Despite facing moderate risks, the Coes Reservoir Dam continues to play a significant role in water management and climate resilience efforts in Worcester. With its strategic location along Tatnuck Brook, the dam serves as a key asset for both recreational enjoyment and environmental protection, highlighting the importance of sustainable water resource management in the region.

Year Completed

1865

Dam Length

600

Dam Height

21

River Or Stream

TATNUCK BROOK

Primary Dam Type

Earth

Surface Area

90

Hydraulic Height

15

Drainage Area

11.5

Nid Storage

1223

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

21
       
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.