Mekong River in Cambodia
Stretch 15: Kompong Chhnang to Chong Kneas about 122 km
The Great Lake is a particularity waterway in the Mekong River System.
The Great Lake is the largest freshwater body in Southeast Asia and a vital part of the Mekong hydrological system. It is furthermore called “the nursery of all migrating fish species in the Mekong”.
The Great Lake (Tonle Sap)’s mean water-surface area changes from 2,500 Km² to 3,500 Km2 during the dry season (January to April-May) to a maximum of up to 14,500 Km2 during the wet season (4-5 times bigger). Water depths up to 9.0 m can be reached (in the dry season not more than 0.7 to 1.0 m) from late September to early October. However, the seasonal storage of water stored in the Great Lake goes from as low as 1 to 2 km³ (= 1 to 2 million m³) to 50 or 80 km³ (= 50 to 80 million m³), or in average 50 times more in the flood season.
The differences between the water level in the Great Lake and the water level at Chaktomuk cause the unique flow reversal in the Tonlé Sap River.
Source: Design of a Master Plan for Regional Waterborne Transport in the Mekong River Basin, Volume I, Page 34, 35