Loch Alsh Reservoir

TR WISSAHICKON CREEK· Montgomery, Pennsylvania· Built 1915· Earth· 16 ft tall
High Hazard Recreation Local Government

Key Takeaway

Loch Alsh Reservoir is classified as high hazard in Pennsylvania. It was completed in 1915 and is 111 years old. Its primary use is recreation. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 16 ft (taller than 32.5% in PA)
Dam Length513 ft
Dam TypeEarth
Max Storage41 acre-ft
Normal Storage36 acre-ft
Surface Area6 acres
Drainage Area0 sq mi
Year Completed1915 (111 years old)
NID IDPA00935

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: Yes
Last Inspection: November 18, 2020
State Regulated: Yes
Regulatory Agency: Pennsylvania Department of Environmental Protection

Ownership

BOROUGH OF AMBLER

Local Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Loch Alsh Reservoir?

Loch Alsh Reservoir is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Loch Alsh Reservoir?

Loch Alsh Reservoir is owned by BOROUGH OF AMBLER (Local Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Loch Alsh Reservoir built?

Loch Alsh Reservoir was completed in 1915, making it 111 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 Loch Alsh Reservoir?

Loch Alsh Reservoir 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 Loch Alsh Reservoir?

Loch Alsh Reservoir has a dam height of 16 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 Loch Alsh Reservoir last inspected?

Loch Alsh Reservoir was last inspected on November 18, 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.