Carraizo Dam

The dam forms the Loiza Lake (Lago Loiza) on the Río Grande de Loiza and serves as a water reservoir to the large metropolitan area of San Juan and adjacent towns. The lake is heavily poluted and is largely covered in parts with water hyacinth which over the years along with hillside runoff has reduced the capacity of the lake by raising the level of sedimentation. The dam was built in 1953.