Sleepy Valley Dam

Sleepy Valley Dam is an earth dam located in Sussex County, New Jersey, built in 1937. It carries a Significant hazard potential classification and has a satisfactory condition assessment.

About Sleepy Valley Dam

The primary purpose of Sleepy Valley Dam is recreation. The dam creates a reservoir used for recreational activities such as fishing, boating, and swimming. The dam is owned by Tall Timbers Property Owners Association (private). It impounds the Wallkill River-tr near Independence Corners.

The dam stands 13 feet tall and stretches 270 feet across, creates a reservoir covering 18 acres, has a maximum storage capacity of 122 acre-feet, and collects water from a drainage area of 1 square miles. Completed in 1937, 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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 11/25/2024.

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Significant HazardSatisfactory ConditionEmergency Action Plan: Yes

Location

StateNew Jersey
CountySussex
Nearest CityIndependence Corners
River/StreamWallkill River-tr
Coordinates41.22052, -74.54143

Physical Characteristics

Dam TypeEarth
NID Height13 ft
Dam Height13 ft
Dam Length270 ft
Year Completed1937 (89 years old)

Storage & Hydraulics

NID Storage122 acre-ft
Max Storage122 acre-ft
Normal Storage81 acre-ft
Surface Area18 acres
Drainage Area1 sq mi
Max Discharge390 cfs

Ownership & Safety

PurposeRecreation
OwnerTall Timbers Property Owners Association
Owner TypePrivate
Hazard ClassificationSignificant
Condition AssessmentSatisfactory
Last Inspection11/25/2024
Emergency Action PlanYes

Identifiers

NID IDNJ00763
Federal IDNJ00763
More InfoState Dam Safety Program

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