Guayo Dam
Guayo Dam is a gravity dam located in Adjuntas County, Puerto Rico, built in 1956. It carries a High hazard potential classification and has a poor condition assessment.
About Guayo Dam
The primary purpose of Guayo Dam is hydroelectric. The dam generates hydroelectric power by channeling water through turbines, converting the energy of flowing water into electricity. The dam is owned by Puerto Rico Electric Power Authority (public utility). It impounds the Guayo River near Espino.
The dam stands 190 feet tall and stretches 555 feet across, creates a reservoir covering 285 acres, has a maximum storage capacity of 19,000 acre-feet, and collects water from a drainage area of 9 square miles. Completed in 1956, the structure is well into its service life at over 50 years old.
This dam carries a high hazard potential classification, which means that a failure or uncontrolled release of water would likely cause loss of human life. This classification reflects the consequences of failure, not the likelihood — it indicates that people live or work in the area downstream. Its condition is rated poor, meaning the dam has recognized safety deficiencies that require remediation to address risks. An emergency action plan is in place for this dam. The most recent inspection on record was 12/11/2021.
At 190 feet, this dam is taller than 99% of all dams in the United States.
Living Downstream
If you live or work downstream of this dam, consider taking these steps: learn your local evacuation routes, check whether your county emergency management office has a dam failure inundation map, and sign up for local emergency alerts. The Puerto Rico dam safety program can provide more specific information about emergency planning for this structure.
Search for dams near your address to see all dams in your area with hazard classifications and safety data.
Location
| State | Puerto Rico |
| County | Adjuntas |
| Nearest City | Espino |
| River/Stream | Guayo River |
| Coordinates | 18.21047, -66.83480 |
Physical Characteristics
| Dam Type | Gravity |
| NID Height | 190 ft |
| Dam Height | 190 ft |
| Dam Length | 555 ft |
| Year Completed | 1956 (70 years old) |
Storage & Hydraulics
| NID Storage | 19,000 acre-ft |
| Max Storage | 19,000 acre-ft |
| Normal Storage | 17,400 acre-ft |
| Surface Area | 285 acres |
| Drainage Area | 9 sq mi |
| Max Discharge | 30,200 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | PUERTO RICO ELECTRIC POWER AUTHORITY |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Poor |
| Last Inspection | 12/11/2021 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PR00005 |
| Federal ID | PR00005 |
| More Info | State Dam Safety Program |