Mirror Lake Dam

Mirror Lake Dam is a gravity dam located in Worcester County, Massachusetts, built in 1913. It carries a Significant hazard potential classification and has a satisfactory condition assessment.

About Mirror Lake Dam

The primary purpose of Mirror Lake Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by City Of Fitchburg (local government). It impounds the Monoosnoc Brook, Tributary To Nashua River near Fitchburg.

The dam stands 15 feet tall and stretches 160 feet across, creates a reservoir covering 7 acres, has a maximum storage capacity of 45 acre-feet, and collects water from a drainage area of 0 square miles. Completed in 1913, the structure is over a century old.

This dam has a significant hazard potential classification, meaning that a failure could cause significant economic damage — flooding roads, bridges, or property downstream — but is not expected to result in loss of life. Its condition is rated satisfactory, indicating no existing or potential dam safety deficiencies are recognized. The most recent inspection on record was 11/19/2020.

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Significant HazardSatisfactory ConditionEmergency Action Plan: No

Location

StateMassachusetts
CountyWorcester
Nearest CityFitchburg
River/StreamMonoosnoc Brook, Tributary To Nashua River
Coordinates42.55871, -71.80071

Physical Characteristics

Dam TypeGravity
NID Height15 ft
Dam Length160 ft
Year Completed1913 (113 years old)

Storage & Hydraulics

NID Storage45 acre-ft
Max Storage45 acre-ft
Normal Storage38 acre-ft
Surface Area7 acres
Drainage Area0 sq mi
Max Discharge139 cfs
Spillway TypeUncontrolled

Ownership & Safety

PurposeRecreation
OwnerCity of Fitchburg
Owner TypeLocal Government
Hazard ClassificationSignificant
Condition AssessmentSatisfactory
Last Inspection11/19/2020
Emergency Action PlanNo

Identifiers

NID IDMA02779
Federal IDMA02779
More InfoState Dam Safety Program

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