Ipswich Mills Dam Reservoir Report

Last Updated: December 20, 2025

The Ipswich Mills Dam, located on the Ipswich River in Massachusetts, was completed in 1900 and serves as a vital water supply structure for the local community.


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Summary

This masonry dam has a height of 10.5 feet and a hydraulic height of 6 feet, with a storage capacity of 300 acre-feet. The dam is regulated by the Department of Conservation and Recreation in Massachusetts and is inspected regularly to ensure its safety and functionality.

Despite being classified as having a low hazard potential, the Ipswich Mills Dam is assessed to be in fair condition as of its last inspection in 2009. With a moderate risk rating of 3, there are ongoing risk management measures in place to address any potential issues that may arise. Although the dam has not been significantly modified in recent years, its primary purpose as a water supply structure remains crucial for sustaining the surrounding area.

For water resource and climate enthusiasts, the Ipswich Mills Dam presents an intriguing case study of a historic masonry dam that continues to play a key role in water supply management in the region. Its location on the Ipswich River and its regulated status by the state highlight the importance of proper maintenance and monitoring of such structures to ensure their continued safety and effectiveness in the face of changing environmental conditions.

Year Completed

1900

Dam Length

180

Dam Height

10.5

River Or Stream

IPSWICH RIVER

Primary Dam Type

Masonry

Surface Area

20

Hydraulic Height

6

Drainage Area

150

Nid Storage

300

Hazard Potential

Low

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.