Altnow Reservoir

WARM SPRING CREEK· Harney, Oregon· Built 1908· Earth· 20 ft tall
Low Hazard Irrigation Private

Key Takeaway

Altnow Reservoir is classified as low hazard in Oregon. It was completed in 1908 and is 118 years old. Its primary use is irrigation.

Physical Details

Dam Height 20 ft (taller than 30% in OR)
Dam Length720 ft
Dam TypeEarth
Max Storage120 acre-ft
Normal Storage122 acre-ft
Surface Area16 acres
Drainage Area1 sq mi
Max Discharge184 cfs
Year Completed1908 (118 years old)
NID IDOR00604

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 28, 2009
State Regulated: Yes
Regulatory Agency: OWRD

Ownership

JOHN AND SUZANNE MOON

Private

Nearby Dams

Cottonwood (Drewsey)

Harney, OR

Significant Hazard 73 ft

Stallard Dam

Harney, OR

Low Hazard 35 ft

Agency Valley

Malheur, OR

High Hazard 110 ft

Scott Dam

Malheur, OR

Low Hazard 18 ft

Sitz Reservoir

Harney, OR

Low Hazard 22 ft

Beede North

Harney, OR

Significant Hazard 12 ft

Beede South

Harney, OR

Significant Hazard 22 ft

Murphy Dam

Malheur, OR

Low Hazard 60 ft

Frequently Asked Questions

What is the hazard classification of Altnow Reservoir?

Altnow 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 Altnow Reservoir?

Altnow Reservoir is owned by JOHN AND SUZANNE MOON (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Altnow Reservoir built?

Altnow Reservoir was completed in 1908, making it 118 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 Altnow Reservoir?

Altnow Reservoir 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 Altnow Reservoir?

Altnow Reservoir has a dam height of 20 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 Altnow Reservoir last inspected?

Altnow Reservoir was last inspected on April 28, 2009. 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.