Norumbega Reservoir Dike #3 Reservoir Report

Last Updated: December 19, 2025

Norumbega Reservoir Dike #3, located in Weston, Massachusetts, is a state-regulated earth dam designed primarily for water supply purposes.


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Summary

Completed in 1940, the dam stands at a height of 42 feet and has a hydraulic height of 34 feet, with a maximum storage capacity of 500 acre-feet and a normal storage of 250 acre-feet. The dam is situated on Seaverns Brook and covers a surface area of 0.06 square miles, with a drainage area of 0.13 square miles.

The dam's spillway type is uncontrolled, and it has a significant hazard potential with a satisfactory condition assessment as of September 2016. The dam is inspected every 5 years, with the last inspection conducted in September 2016. The risk assessment for the dam is moderate, with a DSAC assigned date not available. The dam is owned by the state of Massachusetts and regulated by the Department of Conservation and Recreation, ensuring compliance with state permitting, inspection, and enforcement requirements to manage its water resources effectively and safely. For water resource and climate enthusiasts, Norumbega Reservoir Dike #3 represents a vital infrastructure component in Massachusetts' water supply system, with measures in place to mitigate potential risks and ensure its continued operation.

Year Completed

1940

Dam Height

42

River Or Stream

SEAVERNS BROOK

Primary Dam Type

Earth

Surface Area

0.06

Hydraulic Height

34

Drainage Area

0.13

Nid Storage

500

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

42
       
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.