Jacobs Pond Dam Reservoir Report

Last Updated: December 19, 2025

Jacobs Pond Dam, located in Norwell, Massachusetts, serves as a vital structure for recreational purposes along the Third Herring Brook.


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Summary

Built in 1730, this Earth-type dam stands at a height of 10.5 feet and holds a storage capacity of 650 acre-feet. With a surface area of 55 acres and a drainage area of 1.43 square miles, the dam provides a serene environment for water resource and climate enthusiasts to enjoy nature.

Managed by the Department of Conservation and Recreation in Massachusetts, Jacobs Pond Dam is subject to state regulation and enforcement, with regular inspections conducted to ensure its structural integrity. Despite being classified as having a fair condition assessment, the dam poses a significant hazard potential, with a moderate risk level. Emergency action plans are yet to be prepared, highlighting the need for proactive risk management measures to mitigate potential threats and ensure the safety of surrounding communities.

With its rich history dating back to the 18th century, Jacobs Pond Dam stands as a testament to early engineering feats and continues to be a focal point for outdoor recreation in Plymouth County, Massachusetts. As water resource and climate enthusiasts explore the area, it is crucial to appreciate the balance between conservation efforts and maintaining the dam's functionality to safeguard both the environment and the local community from potential risks associated with its operation.

Year Completed

1730

Dam Length

650

Dam Height

10.5

River Or Stream

THIRD HERRING BROOK

Primary Dam Type

Earth

Surface Area

55

Hydraulic Height

6

Drainage Area

1.43

Nid Storage

650

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

11
       
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.