Tonlé Sap River, Which changes its flow direction twice a year

The Tonlé Sap (translated as “Large Fresh Water River” and most commonly as “Great Lake”), in Cambodia is famous for many unusual things. e.g:

• It is the combined river and lake system of Cambodia.
• It is the largest freshwater lake in South East Asia.
• From November to May, it drains into Mekong River while in rest of the months it flows backwards to form a big lake.

Image credit: Flickr Miguel Vicente Martínez Juan

Tonlé Sap River behaviour:

• The flow of Tonlé Sap River changes its direction twice a year. It flows north for almost six months and then south for rest of the months.
• Another unusual thing about the river is that the portion which forms the lake amazingly shrinks and expands with the change of seasons.
• The lake is small most of the year, its around one meter deep with an area of 2,700 square km but during monsoon season, because of heavy amount of rains the Mekong river reverses its flow towards lake due to which its area is increased to 16,000 square km and depth up to 9 meters.

The area around the lake is also home to many Vietnamese and Cham communities living in different villages.

Tonlé Sap River Specialties: 

• There are more than 100 varieties of waterbirds, over 200 species of fish, turtles, crocodiles and other wildlife is found in the mangrove forests in the surroundings of the Lake.
• One of the most productive inland fisheries in the world, the reason behind this is high annual sediment and rich biodiversity of the river.