Gillespie

GILA RIVER· Maricopa, Arizona· Built 1921· Multi-Arch· 21 ft tall
Significant Hazard Irrigation Private

Key Takeaway

Gillespie is classified as significant hazard in Arizona. It was completed in 1921 and is 105 years old. Its primary use is irrigation. Significant hazard means failure could cause economic or environmental damage. Learn more.

Physical Details

Dam Height 21 ft (taller than 32.9% in AZ)
Dam Length1,768 ft
Dam TypeMulti-Arch
Max Storage3.6K acre-ft
Normal Storage0 acre-ft
Surface Area80 acres
Drainage Area4,965 sq mi
Max Discharge130,000 cfs
Year Completed1921 (105 years old)
NID IDAZ00106

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: Yes
Last Inspection: September 24, 2020
State Regulated: Yes
Regulatory Agency: ARIZONA DEPARTMENT OF WATER RESOURCES

Ownership

GILLESPIE DAM INVESTMENTS, LLC

Private

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Gillespie?

Gillespie 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 Gillespie?

Gillespie is owned by GILLESPIE DAM INVESTMENTS, LLC (Private). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Gillespie built?

Gillespie was completed in 1921, making it 105 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 Gillespie?

Gillespie 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 Gillespie?

Gillespie has a dam height of 21 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 Gillespie last inspected?

Gillespie was last inspected on September 24, 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.