Lake Monomonac Dam Reservoir Report

Last Updated: December 16, 2025

Lake Monomonac Dam in Winchendon, Massachusetts, is a vital water resource for recreation enthusiasts and climate advocates alike.


°F

°F

mph

Wind

%

Humidity

Summary

Completed in 2005, this earth dam stands at a height of 15.5 feet and holds a maximum storage capacity of 4340 acre-feet. The dam's primary purpose is recreation, offering a surface area of 595 acres for water-based activities.

Managed by the Department of Conservation and Recreation, the dam is state-regulated and undergoes regular inspections to ensure its structural integrity. Despite a fair condition assessment, the dam poses a high hazard potential, prompting moderate risk assessment. The North Branch of Millers River flows through this area, enriching the surrounding landscape and contributing to the dam's ecological significance.

Lake Monomonac Dam serves as a critical infrastructure for water management in Worcester County, Massachusetts, highlighting the intersection of environmental conservation and public safety. As climate change continues to impact water resources, the maintenance and regulation of dams like Lake Monomonac become increasingly crucial for sustainable water management practices and community resilience in the face of evolving environmental challenges.

Year Completed

2005

Dam Length

250

Dam Height

15.5

River Or Stream

NORTH BRANCH OF MILLERS RIVER

Primary Dam Type

Earth

Surface Area

595

Hydraulic Height

10.3

Drainage Area

18.5

Nid Storage

4340

Hazard Potential

High

Foundations

Unlisted/Unknown

Nid Height

16
       
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.