St. Mary'S Abbey Lower Dam

Whippany River-TR· Morris, New Jersey· Earth· 13 ft tall
Significant Hazard Recreation Private

Key Takeaway

St. Mary'S Abbey Lower Dam is classified as significant hazard in New Jersey. 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 Length100 ft
Dam TypeEarth
Max Storage15 acre-ft
Normal Storage8 acre-ft
Surface Area4 acres
Drainage Area1 sq mi
Max Discharge845 cfs
NID IDNJ00924

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: November 25, 2021
State Regulated: Yes
Regulatory Agency: NJDEP

Ownership

S. Mary's Abbey;The Order of St. Benedict of NJ

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of St. Mary'S Abbey Lower Dam?

St. Mary'S Abbey Lower 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 St. Mary'S Abbey Lower Dam?

St. Mary'S Abbey Lower Dam is owned by S. Mary's Abbey;The Order of St. Benedict of NJ (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

What is the primary purpose of St. Mary'S Abbey Lower Dam?

St. Mary'S Abbey Lower 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 St. Mary'S Abbey Lower Dam?

St. Mary'S Abbey Lower 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 St. Mary'S Abbey Lower Dam last inspected?

St. Mary'S Abbey Lower Dam was last inspected on November 25, 2021. 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.