Tully Dam Reservoir Report

Last Updated: December 12, 2025

Tully Dam, also known as Tully Lake, is a rockfill dam located on the East Branch Tully River in Athol, Massachusetts.


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Summary

Built in 1949 by the US Army Corps of Engineers, the dam stands at a height of 59 feet and has a storage capacity of 35,800 acre-feet. Its primary purpose is flood risk reduction, with a maximum discharge capacity of 32,700 cubic feet per second.

The dam is classified as having a high hazard potential, and while its condition assessment is not available, an emergency action plan (EAP) is in place to address potential risks. USACE manages dam-related flood risks through continuous monitoring, prioritizing risk-reduction activities, and collaborating with local emergency managers and the public to raise awareness and readiness for potential emergencies. Regular maintenance and repairs are conducted to ensure the dam's structural integrity.

Dams like Tully Dam play a crucial role in managing water levels and mitigating flood risks, but they are not without limitations. The USACE works diligently to address all types of flood risks associated with the dam and to ensure its proper functioning in the face of varying water levels and severe weather events.

Year Completed

1949

Dam Length

1570

Dam Height

59

River Or Stream

EAST BRANCH TULLY RIVER

Primary Dam Type

Rockfill

Surface Area

300

Hydraulic Height

54

Drainage Area

50

Nid Storage

35800

Structural Height

59

Hazard Potential

High

Foundations

Soil

Nid Height

59
       
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.