Oso Largo Dam

GILA RIVER· Graham, Arizona· Built 1971· Gravity·
Low Hazard Flood Risk Reduction Federal Government

Key Takeaway

Oso Largo Dam is classified as low hazard in Arizona. It was completed in 1971 and is 55 years old. Its primary use is flood risk reduction.

Physical Details

Dam Length4,625 ft
Dam TypeGravity
Max Storage617 acre-ft
Normal Storage120 acre-ft
Surface Area241 acres
Drainage Area94 sq mi
Max Discharge5,442 cfs
Year Completed1971 (55 years old)
NID IDAZ20020

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: August 20, 2010
State Regulated: No

Ownership

DOI BLM

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Oso Largo Dam?

Oso Largo Dam 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 Oso Largo Dam?

Oso Largo Dam is owned by DOI BLM (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Oso Largo Dam built?

Oso Largo Dam was completed in 1971, making it 55 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 Oso Largo Dam?

Oso Largo Dam serves the following purposes: Flood Risk Reduction. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

When was Oso Largo Dam last inspected?

Oso Largo Dam was last inspected on August 20, 2010. 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.