Tonle Sap Lake in Cambodia plays a very important role in supplying water to the Mekong Delta. Currently, the water level at Tonle Sap Lake is at the lowest level at 80 centimeters lower than the previous record low in 2020 and almost 4 meters below average.

The reversal flow to Tonle Sap Lake typically begins in June, but this year’s has yet to occur.

Below average rainfall and restrictions from upstream dams are causing the Tonle Sap’s lackluster performance. Dams in Upper Mekong Basin have restricted a total of 12 billion cubic meters of water since early July, or an average of 3000 cubic meters of water per second over the last two months.

All of the dams together have only restricted about 45% of their potential capacity. Historical data suggests that most dams will continue to restrict water in coming months, so expect more dismal performance to come from the Tonle Sap and Mekong mainstream even with increases of rainfall.

Source: Mekong Dam Monitor