Trillium Lake

MUD CREEK· Clackamas, Oregon· Built 1960· Earth· 19 ft tall
Low Hazard Recreation State Government

Key Takeaway

Trillium Lake is classified as low hazard in Oregon. It was completed in 1960 and is 66 years old. Its primary use is recreation.

Physical Details

Dam Height 19 ft (taller than 27.8% in OR)
Dam Length985 ft
Dam TypeEarth
Max Storage380 acre-ft
Normal Storage353 acre-ft
Surface Area65 acres
Drainage Area1 sq mi
Max Discharge450 cfs
Year Completed1960 (66 years old)
NID IDOR00350

Safety Information

Low Hazard

No probable loss of human life and low economic/environmental losses expected.

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

Emergency Action Plan: No
Last Inspection: June 12, 2019
State Regulated: Yes
Regulatory Agency: OWRD

Ownership

OREGON DEPARTMENT OF FISH AND WILDLIFE

State Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Trillium Lake?

Trillium Lake is classified as Low Hazard. No probable loss of human life and low economic/environmental losses expected. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Trillium Lake?

Trillium Lake is owned by OREGON DEPARTMENT OF FISH AND WILDLIFE (State Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Trillium Lake built?

Trillium Lake was completed in 1960, making it 66 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 Trillium Lake?

Trillium Lake 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 Trillium Lake?

Trillium Lake has a dam height of 19 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 Trillium Lake last inspected?

Trillium Lake was last inspected on June 12, 2019. 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.