Mormon Flat

SALT RIVER· Maricopa, Arizona· Built 1924· Concrete· 224 ft tall
High Hazard Hydroelectric Irrigation Federal Government

Key Takeaway

Mormon Flat is classified as high hazard in Arizona. It was completed in 1924 and is 102 years old. Its primary use is hydroelectric. High hazard means loss of life is likely if the dam fails — it does not indicate the dam's current condition. Learn more.

Physical Details

Dam Height 224 ft (taller than 95.8% in AZ)
Dam Length380 ft
Dam TypeConcrete
Max Storage57.9K acre-ft
Normal Storage57.9K acre-ft
Surface Area950 acres
Drainage Area120 sq mi
Year Completed1924 (102 years old)
NID IDAZ10313

Safety Information

High Hazard

Loss of human life is likely if the dam fails.

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

Emergency Action Plan: Yes
Last Inspection: October 12, 2020
State Regulated: No

Ownership

RECLAMATION

Federal Government

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Mormon Flat?

Mormon Flat is classified as High Hazard. Loss of human life is likely if the dam fails. This classification refers to the potential downstream consequences of a failure, not the dam's current structural condition.

Who owns and operates Mormon Flat?

Mormon Flat is owned by RECLAMATION (Federal Government). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Mormon Flat built?

Mormon Flat was completed in 1924, making it 102 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 Mormon Flat?

Mormon Flat serves the following purposes: Hydroelectric, Irrigation. Many dams in the U.S. are multi-purpose, supporting flood control, water supply, recreation, and other uses.

How tall is Mormon Flat?

Mormon Flat has a dam height of 224 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 Mormon Flat last inspected?

Mormon Flat was last inspected on October 12, 2020. 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.