river on Luzon Island, Philippines, rising in several headstreams in the Caraballo Mountains and flowing south for about 120 miles (190 km) to empty into northern Manila Bay in a wide, swampy delta. The Candaba Swamp, covering more than 200 square miles (500 square km) when flooded, has been formed north of the delta where the Angat River joins the Pampanga. Other major tributaries are the Chico Pampanga and the Lubao. There are extensive fishponds and a large-scale irrigation project on the lower course of the Pampanga.