Prieto Dam

PRIETO RIVER· Lares, Puerto Rico· Built 1955· Gravity· 98 ft tall
High Hazard Hydroelectric Irrigation Public Utility

Key Takeaway

Prieto Dam is classified as high hazard in Puerto Rico. It was completed in 1955 and is 71 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 98 ft (taller than 47.2% in PR)
Dam Length260 ft
Dam TypeGravity
Max Storage880 acre-ft
Normal Storage600 acre-ft
Surface Area20 acres
Drainage Area10 sq mi
Max Discharge32,000 cfs
Year Completed1955 (71 years old)
NID IDPR00002

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 Prieto Dam?

Prieto 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 Prieto Dam?

Prieto 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 Prieto Dam built?

Prieto Dam was completed in 1955, making it 71 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 Prieto Dam?

Prieto Dam 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 Prieto Dam?

Prieto Dam has a dam height of 98 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 Prieto Dam last inspected?

Prieto 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.