Wawa Dam (also known as Montalban Dam) is a gravity dam constructed over the Marikina River in the municipality of Rodriguez in Rizal province, Philippines. The slightly arched dam is situated in the 360-metre (1,180 ft) high Montalban Gorge or Wawa Gorge, a water gap in the Sierra Madre Mountains, east of Manila. It was built in 1909 during the American colonial era to provide the water needs for Manila. It used to be the only source of water for Manila until Angat Dam was built and Wawa was abandoned. Due to insufficiency of water supply for Metro Manila, there was a strong clamor to reuse the dam.