Guayo Dam

GUAYO RIVER· Lares, Puerto Rico· Built 1956· Gravity· 190 ft tall
High Hazard Hydroelectric Irrigation Water Supply Public Utility

Key Takeaway

Guayo Dam is classified as high hazard in Puerto Rico. It was completed in 1956 and is 70 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 190 ft (taller than 83.3% in PR)
Dam Length555 ft
Dam TypeGravity
Max Storage19.0K acre-ft
Normal Storage17.4K acre-ft
Surface Area285 acres
Drainage Area10 sq mi
Max Discharge30,200 cfs
Year Completed1956 (70 years old)
NID IDPR00005

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: December 11, 2021
State Regulated: Yes
Regulatory Agency: PREPA

Ownership

PUERTO RICO ELECTRIC POWER AUTHORITY

Public Utility

Nearby Dams

Frequently Asked Questions

What is the hazard classification of Guayo Dam?

Guayo Dam 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 Guayo Dam?

Guayo Dam is owned by PUERTO RICO ELECTRIC POWER AUTHORITY (Public Utility). The owner is responsible for maintenance, inspections, and compliance with dam safety regulations.

When was Guayo Dam built?

Guayo Dam was completed in 1956, making it 70 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 Guayo Dam?

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

How tall is Guayo Dam?

Guayo Dam has a dam height of 190 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 Guayo Dam last inspected?

Guayo Dam was last inspected on December 11, 2021. 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.