Cook Reservoir (Wash)

TUALATIN RIVER, TRIB TO· Washington, Oregon· Built 1972· Earth· 28 ft tall
Significant Hazard Irrigation Private

Key Takeaway

Cook Reservoir (Wash) is classified as significant hazard in Oregon. It was completed in 1972 and is 54 years old. Its primary use is irrigation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 28 ft (taller than 54.8% in OR)
Dam Length160 ft
Dam TypeEarth
Max Storage14 acre-ft
Normal Storage14 acre-ft
Surface Area3 acres
Drainage Area1 sq mi
Max Discharge73 cfs
Year Completed1972 (54 years old)
NID IDOR01430

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
Last Inspection: November 14, 2018
State Regulated: Yes
Regulatory Agency: OWRD

Ownership

RON HOCHSTEIN

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Cook Reservoir (Wash)?

Cook Reservoir (Wash) 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 Cook Reservoir (Wash)?

Cook Reservoir (Wash) is owned by RON HOCHSTEIN (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Cook Reservoir (Wash) built?

Cook Reservoir (Wash) was completed in 1972, making it 54 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 Cook Reservoir (Wash)?

Cook Reservoir (Wash) serves the following purposes: Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Cook Reservoir (Wash)?

Cook Reservoir (Wash) has a dam height of 28 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 Cook Reservoir (Wash) last inspected?

Cook Reservoir (Wash) was last inspected on November 14, 2018. 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.