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Weekly Dry Season Situation Report in the Lower Mekong River Basin - 28 December 2021-03 January 2022

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Key Messages

Key messages for this weekly report are presented below.

Rainfall and its forecast

  • During December 28-January 3, no rainfall was observed over the Mekong region.

  • There will be some rain for the next 7 days over the Mekong region from 4 to 10 January 2022 due to a low-pressure line dominating the Mekong region.

Water level and its forecast

  • The MRC’s observed water level at Jinghong showed a slight increase of about 0.03 m from 535.23 m on 28 Dec 2021 to 535.26 on 3 Jan 2022 (recorded on 7:00 am), and stayed about 0.33 m below its two-year average (2020-2021) value. The outflow was down from 825 m3/s on 28 Dec 2021 to 807 m³/s on 3 Jan 2022.

  • Amid the slightly increased outflow from Jinghong upstream, water level of monitoring station at Chiang Saen in Thailand dropped about 0.09 m from 28 Dec 2021 to 3 Jan 2022 and stayed 0.35 m below its long-term average (LTA), considered critical. Moreover, water level at Lao PDR’s Luang Prabang decreased about 0.19 m compared with last week and stayed close to its historical maximum value. WLs at the monitoring stations from Chiang Khan to Vientiane in Thailand and Lao PDR decreased about 0.05 m and stayed below their LTA value. The current WL from Nong Khai in Thailand to Paksane in Lao PDR are lower than their historical minimum level, which considered very critical. WL from Thailand’s Nakhon Phanom to Savannakhet in Lao PDR decreased about 0.25 m and continued staying below their LTA level. WL at Savannakhet in Lao PDR dropped down to its historical minimum level, which considered very critical. Water levels from the stretches of the river from Stung Treng to Kratie and at Kompong Cham in Cambodia, moreover, were decreasing due to less contributed rainfall from the upstream part (at Pakse and 3S area in Viet Nam).

  • The water volume of the Tonle Sap Lake up to 3 Jan 2022 was lower than its LTA but higher than the levels in 2019, 2020 and 2021 during the same period from 28 December 2021 to 3 January 2022, and still considered critical.

  • Over the next seven days, the water levels across most monitoring stations are expected to go down and remain lower than their long-term average value in most stations.

Drought condition and its forecast

  • Drought condition of the LMB from 26 December 2021 to 1 January 2022 was normal all over the LMB except some moderate drought in north-eastern part due to severely dry soil moistures during the beginning of dry season. The region showed no significant threat except some moderate and severe dry soil moistures in the upper and middle parts of the LMB.

  • For the upcoming three-month forecast, the LMB is likely to receive average rainfall and under normal conditions in January. In February the region is forecasted to get some rain in the lower part of the LMB covering mainly Viet Nam. While, in March it is forecasted that the entire LMB will be much wetter than its long-term mean of March mainly over the central and lower parts of the region.