Diack Reservoir

SANDY RIVER, TRIB OF· Multnomah, Oregon· Built 1955· Earth· 26 ft tall
Low Hazard Irrigation Fish And Wildlife Pond Private

Key Takeaway

Diack Reservoir is classified as low hazard in Oregon. It was completed in 1955 and is 71 years old. Its primary use is irrigation.

Physical Details

Dam Height 26 ft (taller than 49.6% in OR)
Dam Length220 ft
Dam TypeEarth
Max Storage20 acre-ft
Normal Storage20 acre-ft
Surface Area4 acres
Drainage Area0 sq mi
Max Discharge191 cfs
Year Completed1955 (71 years old)
NID IDOR01543

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: April 14, 2015
State Regulated: Yes
Regulatory Agency: OWRD

Ownership

SAMUEL L. DIACK

Private

Nearby Dams

Sester, William H. Reservoir 1

Multnomah, OR

Significant Hazard 32 ft

Belchers Dam

Multnomah, OR

Low Hazard 28 ft

Osburn Reservoir

Multnomah, OR

Low Hazard 34 ft

Lake Roslyn

Clackamas, OR

Significant Hazard 45 ft

Iseli Nursery 4

Clackamas, OR

Low Hazard 20 ft

Kelly Creek Regional Detention Pond

Multnomah, OR

Low Hazard 20 ft

Sandy Farms No. 1-A

Clackamas, OR

Significant Hazard 33 ft

Mt. Hood Community College Dam

Multnomah, OR

Significant Hazard 58 ft

Frequently Asked Questions

What is the hazard classification of Diack Reservoir?

Diack Reservoir 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 Diack Reservoir?

Diack Reservoir is owned by SAMUEL L. DIACK (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Diack Reservoir built?

Diack Reservoir was completed in 1955, making it 71 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 Diack Reservoir?

Diack Reservoir serves the following purposes: Irrigation, Fish And Wildlife Pond. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Diack Reservoir?

Diack Reservoir has a dam height of 26 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 Diack Reservoir last inspected?

Diack Reservoir was last inspected on April 14, 2015. 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.