Garside Reservoir Dam Reservoir Report

Last Updated: December 19, 2025

Garside Reservoir Dam, located in Duxbury, Massachusetts, is a vital earth dam along the South River that serves primarily for irrigation purposes.


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Summary

Managed by the local government, the dam stands at a height of 5 feet and has a hydraulic height of 2 feet, with a length of 490 feet. The reservoir has a storage capacity of 109.7 acre-feet, with a normal storage level of 34.4 acre-feet, covering a surface area of 38 acres.

The dam, constructed with a buttress core type, is regulated and inspected by the Department of Conservation and Recreation in Massachusetts. With a significant hazard potential and fair condition assessment, the dam underwent its last inspection in March 2014 and is scheduled for inspections every five years. While the risk assessment is moderate, further risk management measures and emergency action plans are yet to be prepared, indicating the need for continued monitoring and maintenance to ensure the safety and integrity of the structure for the surrounding community and water resources.

Situated in Plymouth County, Garside Reservoir Dam plays a crucial role in managing water resources along the South River, highlighting the importance of its maintenance and regulatory oversight. As a key component of the local irrigation system, the dam's condition and functionality are essential for sustainable water management and climate resilience in the region.

Dam Length

490

Dam Height

5

River Or Stream

SOUTH RIVER

Primary Dam Type

Earth

Surface Area

38

Hydraulic Height

2

Drainage Area

0.33

Nid Storage

109.7

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

5
       
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.