Professor Trần Thục, chairman of the Vietnam Association of Meteorology and Hydrology, told the Voice of Việt Nam (VOV) online newspaper that Vietnamese central provinces are likely to suffer from severe drought and salt intrusion in the 2019-20 dry season.
Is Việt Nam included in the list of countries seriously hit by water shortage?
Total rainfall in the Mekong basin from early June to July 25 this year is much lower than the average of the same period for many years – by 30 to 70 per cent.
The water levels in the sub-Mekong region are also lower than the average water level for many years by between 2.5 to 5.5m.
The water level in the Mekong Delta region of Việt Nam is also much lower than the level seen in many years in the past.
It is forecast that the sub-Mekong region this year is likely to suffer a serious drought. It means that there will be no flood season in the region – a big threat for many hydro power plants in the upper reaches of the Mekong region and a big problem for salt water infiltration in the Mekong Delta.
In such a situation, many regions in Việt Nam are likely to face serious drought. Is this right?
According to the weather forecast, the El Nino phenomena will last from now till November 2019 with a probability of 50-55 per cent. So with the impact from El Nino, the mean temperature in the whole country will be a bit higher than that of the previous years of between 0.5-1.0 degrees.
According to the weather forecast bureau, in the upcoming two months of August and September, rainfall in the central region will be a bit lower than that of the previous year.
The water in all rivers in the central region will be reduced be between 40-65 per cent. In some localities, like Quảng Nam, Bình Định and Phú Yến, water shortage will be up to 80 per cent.
Meanwhile, the water level in the central region will continue to drop much lower than that in the same period for many years.
Such a situation has led to severe drought in many central provinces from Nghệ An to Khánh Hòa. The hardest hit provinces are Quảng Nam, Quảng Ngãi, Bình Định and Phú Yên. Meanwhile, in the lower basin, some rivers will have the problem of salt water intrusion from late July to early August, 2019.
From now till late 2019, the central region is likely to experience one or two typhoons. As a consequence, heavy rain is likely to occur in the sub Mekong region. Total rainfall in August and September in the upper reaches (Laos and China) is expected to be from 10-20 per cent higher than the average. Meanwhile, in the lower reaches of the Mekong River (in southern Laos and Cambodia), it is forecast that heavy rains will occur. But from October, the dry season will start and the rainfalls will drop quickly.
What is the forecast for the monsoon season and dry season in 2019-20?
From August-October, the total water flow in the Mekong River will be lower than the average by 10-30 per cent, yet between 5-12 per cent higher than that of 2015. It is forecast the peak of the flood is likely to occur in late September or early October this year in the Mekong Delta.
It is forecast that in the dry season 2019-20, the water level in the upper reaches of the Mekong River will be seriously impacted by the tide and the problem of salt water intrusion in the river mouth of the southern region in the dry season 2019-20 will come much earlier than usual, right at the onset of the year 2020. As a result, localities in the Mekong Delta region and the southern region in particular, should develop their plans against drought and salt water intrusion for the 2019-20 dry season as soon as possible.
From the onset of 2019, the National Centre for Hydro-Meteorological Forecasting has come up with a projection that the monthly mean temperature in Việt Nam in general will be higher than that of the previous years while the mean rainfall will be lower than that of the previous years. Meanwhile, water flow in all rivers in the central region will be reduced and early floods in the Mekong River is unlikely to happen as it did in the past.