Caonillas Dam is a concrete dam located in Jayuya County, Puerto Rico, built in 1948. It carries a High hazard potential classification and has a satisfactory condition assessment.
Dam profile
NID height · 235 ft235 ft tall, taller than 99% of U.S. dams with a recorded height. Height is drawn to scale against the Statue of Liberty, 305 ft ground to torch; the profile is a generic concrete gravity section and the water level is illustrative.
About Caonillas Dam
The primary purpose of Caonillas 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 Caonillas River near Arecibo.
The dam stands 235 feet tall, creates a reservoir covering 700 acres, has a maximum storage capacity of 54,970 acre-feet, and collects water from a drainage area of 50 square miles. Completed in 1948, the structure is well-established, with more than 75 years of service.
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 satisfactory, indicating no existing or potential dam safety deficiencies are recognized. An emergency action plan is in place for this dam. The most recent inspection on record was 09/04/2019. That was 7 years ago, which is on the longer end for a high-hazard structure.
At 235 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 | Jayuya |
| Nearest City | Arecibo |
| River/Stream | Caonillas River |
| Coordinates | 18.16936, -66.65136 |
Physical Characteristics
| Dam Type | Concrete |
| NID Height | 235 ft |
| Dam Height | 235 ft |
| Year Completed | 1948 (78 years old) |
Storage & Hydraulics
| NID Storage | 54,970 acre-ft |
| Max Storage | 54,970 acre-ft |
| Normal Storage | 35,182 acre-ft |
| Surface Area | 700 acres |
| Drainage Area | 50 sq mi |
| Max Discharge | 107,000 cfs |
| Spillway Type | Uncontrolled |
Ownership & Safety
| Purpose | Hydroelectric |
| Owner | Puerto Rico Electric Power Authority |
| Owner Type | Public Utility |
| Hazard Classification | High |
| Condition Assessment | Satisfactory |
| Last Inspection | 09/04/2019 |
| Emergency Action Plan | Yes |
Identifiers
| NID ID | PR00011 |
| Federal ID | PR00011 |
| More Info | State Dam Safety Program |