Mekong River in Cambodia
Stretch 14: Phnom Penh Chaktomuk to Kompong Chhnang about122 km
The Tonlé Sap waterway is a particularity in the Mekong River System. The flow in the Tonlé Sap changes twice its direction per year.
The Tonlé Sap navigation branch starts from a width of 420.0 m at the river mouth at Chaktomuk to barely 80.0 m midway (because the main Tonlé Sap river branch is used by the fishermen over the entire width of the channel for their fishing activities). The small western river arm is also the only channel that passes the port of Kompong Chhnang.
Chhnock Trou is the last river port before the Great Lake. The river is extremely wide and very shallow. The UHA atlas gives negative water depths for the channel entrances (above chart datum), whilst the earlier referenced feasibility study on dredging in the Tonlé Sap mentions that the average water depth of the Great Lake is not more than 0.7 m during the low water season.
Source: Design of a Master Plan for Regional Waterborne Transport in the Mekong River Basin, Volume I, Page 34, 35