The central region is at high risk of drought from March to May, the remaining months of this dry season. — Photo baoquangngai.vn

Thu Vân

With the country overwhelmed by fear of the novel coronavirus, another even more severe threat is slowly approaching in the south: the death of the Mekong Delta.

Late last month, farmers in the region made headlines after deciding to sell topsoil from their rice fields because they were unable to grow anything anymore. 

In 2016, the central and southern regions in Việt Nam experienced their worst drought and salt intrusion in 100 years, with 18 provinces declaring a state of emergency at the same time.

In many areas in Trà Vinh, Bến Tre, Kiên Giang and Bạc Liêu, up to 80 per cent of rice crops were lost, and one million people were left in dire need of food assistance. Almost two million people lost their livelihoods or were badly affected. 

The scenario may return this year, and possibly even worse.

The provinces of Long An, Tiền Giang, Bến Tre, Kiên Giang and Cà Mau all declared a state of emergency earlier this month.

Officials said the drought and salinity this year had been way more severe than in 2016, citing salinity levels that had surpassed the 2016 record.

Around 40,000 hectares of rice paddies have been damaged, while water shortages are rampant. Some 90,000 people have insufficient access to water for drinking and domestic use.

In many provinces in the southwestern area, people are having to pay VNĐ200,000 for a cubic meter of fresh water.

The Mekong Delta, home to 19 million people, or 21 per cent of Việt Nam’s population, produces over 90 per cent of the country’s exported rice, and more than 60 per cent of the country’s seafood.

And it is just halfway into the dry season, which starts in late November and lasts until May. Experts say saline intrusion and drought will be even harsher in the next two months.

The ongoing drought and saline intrusion can be blamed partly on climate change, but sadly, experts say it is largely caused by anthropogenic impacts.

Water used for farming and domestic life in the Mekong Delta comes mainly from upstream branches of the Mekong River. But water stored in dams upstream, along with growing water consumption, are likely to make drought and saline intrusion in the area longer-lasting.

In the past seven years, seven super hydropower plants were built on the Mekong River, with six in China.

On February 20, Chinese Foreign Minister Wang Yi said at the fifth Lancang-Mekong Cooperation Foreign Ministers’ Meeting in Vientiane, Laos that China would help its downstream neighbours cope with the prolonged drought by releasing more water from its dams.

But even if China releases water from its hydropower dams, it might not reach the Mekong Delta in Việt Nam, which is 3,000km away, soon enough.

Groundwater exploitation is also adding to the situation, accompanied by sand mining.

As upstream dams prevent floodwaters from irrigating the fields, millions of wells are drying up at an alarming rate.

According to a research paper titled “Impacts of 25 years of groundwater extraction on subsidence in the Mekong Delta, Vietnam” (Mindehoud et al) in 2017, over the past 25 years, the delta had sank on average 18cm as a consequence of groundwater withdrawal, which was used to meet growing agricultural, industrial and domestic demand that fuelled the rapidly growing economy.

Isn’t it ironic that although the Mekong Delta is one of the biggest river basins on the planet, the surface water cannot be used due to pollution, and people have to resort to extracting water from the ground?

As subsidence rates accelerate, it strongly increases the delta’s vulnerability to flooding, salinisation and coastal erosion. The faster the ground sinks, the faster salinity intrusion happens.

The practice of three rice crops a year is another element to the problem.

In the 1980s, farmers in the delta only grew one crop per year. But when the country started to export rice in 1989, things changed. Farmers kept on increasing rice fields, and since the land was limited, they moved to intensive farming with multiple crops, making Việt Nam one of the world’s greatest rice producers.

But the Mekong Delta had to pay the price.

With more crops, more water is needed. In dry seasons, there’s no more supplementary flow from the soil, which makes salinity intrude further.

Finally, water pollution. The surface water in the Mekong Delta has become so polluted due to livestock breeding, industrial production and fisheries. It can’t be used, anymore.

What to do?

What Việt Nam needs to do now is not to wait for water coming from China’s promise, but find ways to save itself in advance.

Nguyễn Ngọc Huy, a climate change expert with the Department of Climate Change and Development at the Vietnam Japan University, has proposed some solutions to help the situation in the long run.

He recommends building a system of reservoirs in the delta, from small to large-size, from family-scale to provincial-scale. These reservoirs can be built on river branches, canals and areas connecting river systems.

Building reservoirs will require other construction work and financial resources, but in the long run, Huy said it would be more cost-effective than the current construction of sluices to stop saline intrusion.

If sluices are built to prevent saline intrusion, dykes will also have to be built along with them since the Mekong Delta was formed by silt.

“Local residents will never be able to afford to build dykes,” Huy said.

Furthermore, the construction of such sluices has a severe impact on biodiversity. River gates are where fish migrate to lay their eggs, but when sluices are built, fishes can’t lay their eggs and numbers decrease. The fruitful fisheries hub of the Mekong Delta would soon disappear.

Huy also emphasised the need to stop exploiting groundwater and shifting to more saline tolerant agricultural production such as alternating rice and shrimp. Forsaking the third crop was a must, and this needed to be encouraged and monitored by a committee, Huy said.

The Mekong Delta can feed its residents for the time being, but whether the delicate relationship will be disrupted by internal development errors remains to be seen.

The facts are there, the figures are there, the delta is sinking, drying up. The important thing is we need to realise that almost these changes to the Mekong Delta are man-made, and it's now our turn to do something to return the land to how it used to be.

The situation is much worrying, but fortunately nature is highly resilient. Whether the people of Việt Nam can return the delta to its previous state is up to them. We know what will happen. It won't happen overnight, but this is a disaster waiting to happen. That is real. Can we transform the agriculture from production-focused to quality focused? Can we stop sand mining and ground water extraction? Can we reduce the number of annual rice harvests? The future is in our hands. — VNS