The Mekong River Commission (MRC) warned Tuesday that the delayed reversal of the Tonle Sap River could adversely affect fish spawning and agricultural production.
In a weekly situation report, the MRC’s Regional Flood and Drought Management Centre in Phnom Penh said water levels were below long-term averages in Stung Treng, Kratie, Kampong Cham and Neak Luong on the Mekong River.
Water levels at Chaktomuk and Koh Khel on the Bassac River and at Phnom Penh Port and Prekdam on the Tonle Sap River were also below their long-term averages.
As of Monday, the annual reversal of the Tonle Sap River — caused by the volume of water flowing downstream along the Mekong — had “not happened yet,” the report said.
Low inflows from the Mekong and less rainfall in sub-catchments around the Tonle Sap could be the reason for the “critical situation” of the lake, it said.
“More than half of the annual inflow to the lake originates from the Mekong mainstream,” the report said.
“Thus, flow alterations in the mainstream would have direct impacts on the Tonle Sap water levels and hydrology,” it added.
“The low volume flow of the Tonle Sap Lake could affect the surrounding floodplain for fish spawning in the flooded forest,” the report said.
It could also lead to a “water shortage for agricultural production” in the area.
The center said lower water levels along the Mekong mainstream in June and July reflected “less rainfall” from catchments and a prolonged El Nino phenomenon.
At the same time, low inflows from upstream since June reflected “reservoir operation and water retention from upstream on the mainstream and tributaries.”
The report noted that tributaries in central Laos along with those in southern Laos and northern Cambodia accounted for more than 40 percent of Mekong flows. China contributes about 16 percent of the flows, it said. Sao Da – AKP