Fernwood Lake South Dike Reservoir Report

Last Updated: December 20, 2025

Fernwood Lake South Dike, a local government-owned structure in Gloucester, Massachusetts, serves a primary purpose of recreation along the Annisquam River.


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Summary

Built in 1877, this earth dam stands at a height of 8 feet and stretches 325 feet in length. With a storage capacity of 317 acre-feet, the dam covers a surface area of 28 acres and drains a 0.52 square mile watershed.

Despite its historic significance, Fernwood Lake South Dike is classified as having a significant hazard potential and poor condition assessment. The last inspection in March 2017 revealed the need for improvements to meet safety standards. The dam is regulated by the Department of Conservation and Recreation in Massachusetts, with state permitting, inspection, and enforcement in place.

Water resource and climate enthusiasts interested in the conservation and management of dams like Fernwood Lake South Dike can explore the challenges associated with aging infrastructure and the importance of proactive risk assessment and maintenance to ensure public safety and environmental protection. With its location in a picturesque setting along the Annisquam River, the dam continues to provide recreational opportunities while highlighting the need for ongoing monitoring and stewardship of our water resources.

Year Completed

1877

Dam Length

325

Dam Height

8

River Or Stream

ANNISQUAM RIVER

Primary Dam Type

Earth

Surface Area

28

Hydraulic Height

8

Drainage Area

0.52

Nid Storage

317

Hazard Potential

Significant

Foundations

Unlisted/Unknown

Nid Height

8
       
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.