Francis P. Ryan Dam Reservoir Report

Last Updated: December 5, 2025

Francis P.


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Summary

Ryan Dam, located in Whately, Massachusetts, serves as a vital water supply structure for the region. Completed in 1970, this earth dam stands at a height of 79.5 feet and has a maximum storage capacity of 2820 acre-feet. The dam's primary purpose is to support water supply needs, with a normal storage capacity of 2460 acre-feet and a surface area of 78.72 acres.

Managed by the local government, the Francis P. Ryan Dam is regulated by the Department of Conservation and Recreation in Massachusetts. It is subject to state permitting, inspection, and enforcement to ensure its safe operation. With a high hazard potential but fair condition assessment as of September 2016, the dam presents a moderate risk level (3) according to the risk assessment.

Water resource and climate enthusiasts will find Francis P. Ryan Dam an intriguing structure within the West Brook river system. Its role in providing essential water supply services, coupled with its regulatory oversight and risk management measures, showcases the importance of maintaining and monitoring dams for both public safety and environmental sustainability.

Year Completed

1970

Dam Length

940

Dam Height

79.5

River Or Stream

WEST BROOK

Primary Dam Type

Earth

Surface Area

78.72

Hydraulic Height

74.8

Drainage Area

4.4

Nid Storage

2820

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

80
       
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.