Many experts have blamed the high intrusion of salty water into the Cửu Long (Mekong) Delta on climate change and the low level of water running from the upper reach to the lower reach of the Mekong River delta. How do you respond to their arguments?

Based on our hydrometereological data and the water level in the Cửu Long (Mekong) Delta, in Southern Việt Nam, over the past 30 years, I can say that there are two main causes of drought in the Cửu Long Delta: water coming from the upper reach of the Mekong River (accounting for over 90 per cent) and the rainfalls in the region, plus the use of water in the Delta coupled by impacts from the sea.

This year, the rainfall in the Cửu Long Delta has been extremely low – a record low in history. No rain was reported in February. As a result, it has seriously affected the water flow in the Mekong River, including the portion running through Việt Nam.

The rainfall is low while the demand for water in all countries sharing the Mekong River is high, and Việt Nam is situated at the lower end of the river. This has resulted in a serious drought in the Cửu Long Delta. According the our hydrometerreological data at the Tân Châu and Châu Đốc stations on the Tiền and Hậu Rivers, the water levels in these two stations were also at their lowest levels in their log books.

In Việt Nam, late March and early April will be the peak of the dry season in Việt Nam. So, the situation will become more serious in the next two months.

In addition, poor water regulation among projects in the Mekong basin has contributed to the problem of water scarcity in the lower basin. At present, on the main tributary of the Mekong River, there are already a few Chinese projects and other international projects built on the main tributary. Due to drought, they don’t discharge water down to the lower end of the river. In addition, Thailand has also built some projects causing the diversion of water in the region. All these activities have rendered the drought in the lower Mekong Delta more serious.

For our Cửu Long Delta, the low rainfall in January and February coupled with high tides has worsened the intrusion of salty water into the Delta.

Does the Mekong River Commission have conducted any impact assessment of reservoirs on the upper reach of the Mekong River on the region’s socio-economic development?

Over the past three years, the Vietnamese Government has assigned the Việt Nam National Mekong Committee to conduct studies on the impacts of hydropower plants on the main tributary of the Mekong River in the Cửu Long Delta Region and the Cửu Long Delta of Việt Nam and Cambodia as a whole. The latest study was completed in December 2015 and sent to the Government.

According to the study, hydropower plants built on the main tributary of the Mekong River and some projects in China’s Yunnan Province have caused serious consequences for the river flow of the Mekong River, particularly in the dry season. It is the main cause of saltwater intrusion into the Cửu Long Delta region in Việt Nam. In addition, it also has negative impacts on Việt Nam’s aqua products and alluvium.

According to the latest report, the volume of aqua products from the Cửu Long Delta will drop by 50 per cent while the alluvium will drop by 70 per cent. This will seriously affect the local people’s livelihoods, the region and the country’s socio-economic development.

At present, there are three major hydropower plants on the upper reach of the Mekong River: one belonging to China (it is already in operation), and the other two – Don SaHong and Xayaburi - are from Laos and are in the process of being constructed.

In the context of climate change, what should countries sharing the Mekong River do to balance the interests of each nation?

All nations have a right to pursue their socio-economic development goals. But during their exploitation of the Mekong River, they should respect international laws and practices, particularly the use of water resources - which was adopted by the UN General Assembly on May 21, 1997 and came into effect in 2014 - and the Co-operation Agreement on the Sustainable Development of the Mekong River in 1995.

As a member of the Mekong River Commission (MRC), Việt Nam has regularly exchanged information with Cambodia and Thailand on the use of water on the Mekong River.

In the near future, the MRC will send a letter of request to China to ask it to consider issues related to tapping water from the Mekong River. — VNS