Lake Lanao

Lake Lanao or Ranaw is a large lake in the Philippines, located in Lanao del Sur province in the country's southern island of Mindanao. With a surface area of 340 km². (131 square miles), it is the largest lake in Mindanao, and the second largest lake in the Philippines and counted as one of the 15 ancient lakes in the world. The lake was formed by the tectonic-volcanic damming of a basin between two mountain ranges and the collapse of a large volcano. It has a maximum depth of 112 meters, and a mean depth of 60.3 meters. The basin is shallowest towards the north and gets progressively deeper towards the south. The lake is fed by four rivers. Its only outlet is the Agus River, which flows southwest into Iligan Bay via two channels, one over the Maria Cristina Falls and the other over the Linamon Falls. A hydroelectric plant installed on the Lanao Lake and Agus River system generates 70% of the electricity used by the people of Mindanao.