Lake Roslyn

BIG AND LITTLE SANDY RIVERS· Clackamas, Oregon· Built 1959· Earth· 45 ft tall
Significant Hazard Hydroelectric Public Utility

Key Takeaway

Lake Roslyn is classified as significant hazard in Oregon. It was completed in 1959 and is 67 years old. Its primary use is hydroelectric. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 45 ft (taller than 80.5% in OR)
Dam Length8,000 ft
Dam TypeEarth
Max Storage2.0K acre-ft
Normal Storage2.0K acre-ft
Surface Area152 acres
Drainage Area5 sq mi
Max Discharge800 cfs
Year Completed1959 (67 years old)
NID IDOR00543

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: No
State Regulated: Yes
Regulatory Agency: OWRD

Ownership

PGE

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Lake Roslyn?

Lake Roslyn 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 Lake Roslyn?

Lake Roslyn is owned by PGE (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Lake Roslyn built?

Lake Roslyn was completed in 1959, making it 67 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 Lake Roslyn?

Lake Roslyn serves the following purposes: Hydroelectric. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Lake Roslyn?

Lake Roslyn has a dam height of 45 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.

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.