Río Grande de Arecibo

The Río Grande de Arecibo is a river of Puerto Rico. The Arecibo River is the fourth longest and second largest in discharge in Puerto Rico, after the Loíza River. Its headwaters lie in the mountains to the south of Adjuntas, from there it flows northward, passing along a gorge that is 200 m deep and 800–1,200 m wide, until it reaches the Atlantic Ocean near Arecibo Pueblo. The tributaries lie along the north side of the Cerro de Punta and the Utuado Pluton.
The tributaries to Río Grande de Arecibo basin include the Vacas, Pellejas, Garzas, Saltillo, Cidra, Grande de Jayuya, Caguana, Caonillas, Yunés, Limón, Jauca, Tanamá and Santiago rivers.

Flood control project

In mid 2018, the United States Army Corps of Engineers announced it would be undertaking a major flood control project of the river, with a budget of $82.9 million.
In mid 2021, funding was appropriated for work on the Río Grande de Arecibo, including work to improve the natural habitat of local species, including the Puerto Rican crested toad and a Río Grande de Arecibo canalization project was set to begin in 2023.