Sleepy Valley Dam

Wallkill River-TR· Sussex, New Jersey· Built 1937· Earth· 13 ft tall
Significant Hazard Recreation Private

Key Takeaway

Sleepy Valley Dam is classified as significant hazard in New Jersey. It was completed in 1937 and is 89 years old. Its primary use is recreation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 13 ft (taller than 39.5% in NJ)
Dam Length270 ft
Dam TypeEarth
Max Storage122 acre-ft
Normal Storage81 acre-ft
Surface Area18 acres
Drainage Area2 sq mi
Max Discharge390 cfs
Year Completed1937 (89 years old)
NID IDNJ00763

Safety Information

Significant Hazard

No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities.

Hazard potential describes downstream consequences of failure, not the dam's current condition. What does this mean?

Emergency Action Plan: Yes
Last Inspection: October 28, 2020
State Regulated: Yes
Regulatory Agency: NJDEP

Ownership

Tall Timbers Property Owners Association

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Sleepy Valley Dam?

Sleepy Valley Dam is classified as Significant Hazard. No probable loss of human life, but can cause economic loss, environmental damage, or disruption of lifeline facilities. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Sleepy Valley Dam?

Sleepy Valley Dam is owned by Tall Timbers Property Owners Association (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Sleepy Valley Dam built?

Sleepy Valley Dam was completed in 1937, making it 89 years old. Many U.S. dams were built between the 1930s and 1970s during a period of major infrastructure investment.

What is the primary purpose of Sleepy Valley Dam?

Sleepy Valley Dam serves the following purposes: Recreation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Sleepy Valley Dam?

Sleepy Valley Dam has a dam height of 13 ft. Dam height is measured from the natural streambed at the downstream toe to the top of the dam, and may differ from the visible height.

When was Sleepy Valley Dam last inspected?

Sleepy Valley Dam was last inspected on October 28, 2020. Inspection dates indicate when a formal review occurred, not the results of that inspection.

Data from the National Inventory of Dams (NID) maintained by the US Army Corps of Engineers. Dam conditions may have changed since the last update. This site is not affiliated with USACE. Do not use for emergency planning — contact your local dam safety program.