Rolling Reservoir Report

Last Updated: December 17, 2025

Rolling is a private hydroelectric dam located in Lowell, Massachusetts, along the Merrimack Canal.


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Summary

Built in 1835, this masonry dam stands at 18 feet high with a storage capacity of 4,500 acre-feet. The primary purpose of Rolling is for hydroelectric power generation, but it also serves other functions such as fire protection, flood risk reduction, navigation, and recreation.

Managed by the Federal Energy Regulatory Commission, Rolling has a low hazard potential and a moderate risk assessment rating. The dam features an uncontrolled spillway with a width of 16 feet and a maximum discharge capacity of 226 cubic feet per second. While the condition assessment of Rolling is currently unavailable, it undergoes inspections every three years to ensure its structural integrity and safety.

With its historical significance and multifaceted functions, Rolling serves as a vital infrastructure for water resource management and climate resilience in Middlesex County, Massachusetts. As water resource and climate enthusiasts, understanding the role of dams like Rolling in sustainable energy production and environmental protection is crucial for promoting a balanced approach to water management and climate adaptation in the region.

Year Completed

1835

Dam Length

18

Dam Height

18

River Or Stream

Merrimack Canal

Primary Dam Type

Masonry

Surface Area

720

Hydraulic Height

13

Nid Storage

4500

Structural Height

18

Hazard Potential

Low

Foundations

Unlisted/Unknown

Nid Height

18
       
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.