Lanao, also known as Ranau, is the largest lake in the island of Mindanao, located in the province of South Lanao. The lake has a total area of 340 square kilometres, 33 kilometres long and 20 kilometres wide. The maximum depth of the lake is 112 metres, the average depth is 60.3 metres. Lanao is considered one of the 15 oldest lakes in the world. Another is its location at an altitude of 700 metres above sea level. On the Lanao's low-lying and flat shores, rice farming is common.
There are 4 rivers flowing into the lake, but only one - Agus, which then empties into the Gulf of Iligan. The river is notable for the beautiful Maria Cristina Falls, sometimes called the "twin waterfalls". There is also a hydroelectric plant a hydroelectric power plant that supplies up to 70% of the electricity needs for the people of Mindanao.
Lanao is the subject of many myths and legends of the local Maranao tribe - the very name of this tribe means "people living on the shores of the lake". The myths describes the origin of the lake as follows: long ago, angels led by the led by the Archangel Gabriel, moved the inhabitants of one city to another place so that the world would not from overpopulation. But the resulting void was soon filled filled with water that nearly flooded the rest of the world. To to avert disaster, the angels called upon the four elements to help them made a hole and the water flowed out - thus Lake Lanao and the Agus River were formed.
In 1992, the lake was declared a watershed reserve - meaning that the the vegetation on its shores and the flow of water are under special protection to water supply for hydroelectric power, irrigation systems and agriculture. The reserve covers an area of 153,000 hectares. On its territory one can find a great variety of flora and fauna, including several species of carp fish, which are endemic to the area. Back in the early 1980s, scientists were were concerned that these species were on the verge of extinction due to the adverse and the introduction of alien species. Thus, due to the appearance of white gobies in the waters of the lake, the population of cyprinids has decreased significantly - out of 18 species, only 5 remain today.
