Situation Report on Dry Season Hydrological Conditions in the Lower Mekong River Basin: November 2020–May 2021

This Situation Report presents a preliminary analysis of the Lower Mekong River Basin hydro-meteorological conditions over the 2020–2021 dry season. It shows fluctuations in water levels in the upper reaches of the Mekong mainstream in Lao PDR and Thailand, as well as low water volume stored in the Tonle Sap Lake. Rainfall in April–May was the highest on record for these months for the last 18 years in places. Overall, flows in the Mekong in the first five months of 2021 were also higher than the long-term average, except for December 2020 where flows in the Mekong mainstream were closer to normal. But river flows did not increase significantly.