Grover's Mill Dam

Grover's Mill Dam is an earth dam located in Mercer County, New Jersey, built in 1931. It carries a Significant hazard potential classification and has a fair condition assessment.

About Grover's Mill Dam

The primary purpose of Grover's Mill Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Township Of West Windsor (local government). It impounds the Big Bear Brook near West Windsor.

The dam stands 15 feet tall and stretches 430 feet across, creates a reservoir covering 45 acres, has a storage capacity of 150 acre-feet, and collects water from a drainage area of 12 square miles. Completed in 1931, the structure is well-established, with more than 75 years of service.

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 fair — the dam has minor deficiencies that are being addressed or do not pose an immediate safety threat. An emergency action plan is in place for this dam. The most recent inspection on record was 03/19/2024.

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Significant HazardFair ConditionEmergency Action Plan: Yes

Location

StateNew Jersey
CountyMercer
Nearest CityWest Windsor
River/StreamBig Bear Brook
Coordinates40.31482, -74.60820

Physical Characteristics

Dam TypeEarth
NID Height15 ft
Dam Height15 ft
Dam Length430 ft
Year Completed1931 (95 years old)

Storage & Hydraulics

NID Storage150 acre-ft
Normal Storage150 acre-ft
Surface Area45 acres
Drainage Area12 sq mi
Max Discharge480 cfs

Ownership & Safety

PurposeRecreation
OwnerTownship of West Windsor
Owner TypeLocal Government
Hazard ClassificationSignificant
Condition AssessmentFair
Last Inspection03/19/2024
Emergency Action PlanYes

Identifiers

NID IDNJ00155
Federal IDNJ00155
More InfoState Dam Safety Program

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