Lower Mekong Basin
Tonle Sap inhabitants
The Lower Mekong Basin (LMB) encompasses the lower half of the Mekong river's length of 2,600 km (1,600 mi) and the surrounding catchment area of around 607,000 km2 (234,000 sq mi). It is divided into five rather distinct physiographic units: the Northern Highlands; the Annamite Chain; the Southern Uplands; the Korat Plateau; and the Mekong Plain. These regions each have distinct geology, climate, vegetation and human-use patterns.
The Lower Mekong Basin (LMB) encompasses the lower half of the Mekong river's length of 2,600 km (1,600 mi) and the surrounding catchment area of around 607,000 km2 (234,000 sq mi). It is divided into five rather distinct physiographic units: the Northern Highlands; the Annamite Chain; the Southern Uplands; the Korat Plateau; and the Mekong Plain. These regions each have distinct geology, climate, vegetation and human-use patterns.
The Lower Mekong Basin rests on an ancient block of continental crust, that has remained relatively stable since the Jurassic Period, a period of over 150 million years. Large areas were covered by an inland sea during the upper Mesozoic Era, during which thick red-bed sandstones and evaporites were deposited.
The Sekong, Sesan, and Srepok rivers - collectively called the 3S Basin - are the dominant tributaries. All three enter the Mekong on the eastern bank. At the southern end of the Basin, the mainstream breaks up into a complex network of branching and reconnecting channels. One of these branches forms the Tonle Sap River. The western and central parts of the southern Basin make up the Great Lake
The Lower Mekong Basin experiences two monsoon periods, rainy from May to October and a dry season from November to March. The annual rainfall is between 1,000 and 3,000 mm, locally up to 4,000 mm, falling almost entirely during the rainy season.[9] Water levels reach their highest in September and October.
