Before the 2024 dry season hit, Võ Văn Kêu thought his rambutan orchard in Vietnam’s Mekong Delta was safe – at least for another year.
Severe drought has become a grim fixture in this fertile southern region. One of its most damaging effects is the inland creep of saltwater, which contaminates freshwater sources and harms crops. This time, Kêu believed he was protected by two newly built sluice gates – Tân Phú and Bến Rớ – multimillion-dollar structures funded by the Japan International Cooperation Agency (JICA) and promoted as part of Bến Tre province’s climate adaptation strategy.
Designed to block saltwater and store freshwater in the upper reaches of the Ba Lai River, farmers found gates unreliable during the peak of the March 2024 drought. Bến Rớ reportedly failed due to a faulty gasket, leaking saltwater into the very canals they were supposed to safeguard, while Tân Phú did not work at all, with farmers living nearby telling Dialogue Earth they believed it was left open for boat traffic.
For Kêu, earlier droughts and saltwater intrusion in 2020 and 2022 had already left scars. At 75, this cycle was familiar to him. “Just because the saltwater retreats… doesn’t mean it’s over,” he said. “It takes at least two or three years to recover from one drought.”
Young shoots die, fruit disappears the following season, and farmers pour money into fertiliser, pesticides, labour and canal maintenance – only to see meagre returns from their harvests.
“And just when the rambutan finally bounces back, another drought hits,” Kêu said. In both 2020 and 2022, he lost half his crops, while costs doubled from having to buy farming supplies to start over. Many neighbours, buried in debt after 2020, pivoted to higher-value durians, only to watch them wither in 2024 when the new sluice gates failed to keep the saltwater out.
Across the Mekong Delta, costly infrastructure projects are being rolled out to defend against drought and saltwater intrusion. Yet while Vietnam’s Resolution 120, implemented in 2017, promised a new climate adaptation strategy – one rooted in “living with water” through nature-based solutions and flexible management – the reality on the ground tells a different story. In practice, projects like sluice gates, dams and large reservoirs, often backed by international loans, are reinforcing a decades-old model of hard engineering which Resolution 120 sought to leave behind.
It’s like riding on a tiger’s back – once you start, you can’t get offLê Anh Tuấn, scientific advisor at the Research Institute for Climate Change, on how hard infrastructure locks communities into debt
Experts warn that labelling such projects as “climate adaptation” – as the funders themselves often do – is misleading. “What these infrastructures do is not ‘living with nature’ – they’re really just moving the problem around,” said Lizzie Yarina, a Northeastern University professor specialising in climate adaptation and Mekong Delta planning. “You keep either salinity or flood out of one place, it goes somewhere else. This means the only way to keep ‘solving’ it is to build more and more infrastructure.”
Lê Anh Tuấn, scientific advisor for the Research Institute for Climate Change at Can Tho University, said the sluice gate system that includes Tân Phú and Bến Rớ is actually pushing salinity into areas like Kêu’s fruit-growing neighbourhood, historically unfamiliar with saltwater. He likens the current approach to squeezing a leaky hose: block one spot and pressure builds elsewhere – usually further inland. “They claim to respond to climate change, but it’s the wrong kind of response,” he said.
Worse, poorly designed infrastructure risks locking communities into debt and environmental degradation for decades. “It’s like riding on a tiger’s back – once you start, you can’t get off,” Lê Anh Tuấn added. The more tightly one tries to control water in the Delta, the more fragile and costly the system becomes.
Earlier transformations: ‘taming’ the water
This reliance on hard infrastructure is nothing new and is what originally helped transform the Mekong Delta into one of the world’s most productive agricultural regions.
In the past 150 years, human intervention drastically reshaped the landscape. During French colonisation, canals were carved and floodplains drained to convert swamps into rice fields for export. After the Vietnam War, the Vietnamese government followed suit with more dikes, sea walls and sluice gates, enabling year-round rice cultivation across nearly every corner of the Delta. The ability to open, close and seal off parts of the Delta from the sea and floods also allowed fruit trees like durian, rambutan and longan to thrive in areas naturally prone to flooding and salinity.
In the 1990s and 2000s, a new “freshening coastal zones” policy aimed to push freshwater into salt-dominated provinces using irrigation infrastructure, effectively turning the area into a three-rice-crop-a-year farming region.
One of the most ambitious undertakings under this policy was the Ba Lai Irrigation Project, launched in 2000 in Bến Tre province. Using a network of dams, dikes and sluice gates, the project aimed to trap and store freshwater behind a river-mouth dam, shielding half the low-lying province from saltwater intrusion.
For a time, it worked. Farmer families like Lê Thị Phương’s started growing rice year-round. The increased income allowed her to raise cows – her “savings” – and build a new brick house beside the field
“But since 2020, I haven’t dared to grow the third crop in the dry season,” she said. The 2019-2020 dry season saw severe drought and deep seawater intrusion wipe out her rice harvest and kill all nine of her cows. “They couldn’t survive drinking salt water,” she said. “We struggled to find water for [even] ourselves.”
Projects like Ba Lai struggled to keep up. Bến Tre became the epicentre of that season’s historic drought, in which increased salinity affected 10 of the Delta’s 13 provinces. This was just the second of what has become a relentless cycle of droughts and salinisation. In 2016, a severe drought, worsened by El Niño, pushed saltwater 90 kilometres inland. The coast was hit again in 2022, and then again in 2024, reinforcing fears that extreme droughts and salinisation are the new normal. “While the Mekong Delta is no stranger to saline intrusion, the intensity and frequency is unprecedented,” said Lê Anh Tuấn.
These cascading disasters signal a breaking point. Upstream dams, particularly in China and Laos, have cut off much of the Mekong’s natural flow and sediment, weakening its natural freshwater defences against rising seas. Rising temperatures are also disrupting rainfall.
Scientists warn that if current trends in sea level rise continue, more than 45% of the Delta could be submerged within decades, displacing millions and jeopardising Vietnam’s food security. Saline intrusion alone has cost Mekong Delta farmers an estimated USD 2.8 billion over the past decade.
Environmental changes could cost the Delta billions if adaptation efforts fall short. A 2021 study estimates GDP losses of 4.5% at 1.5C global warming, rising to up to 10.8% under a 3C scenario.
All this highlights a harsh new reality: as freshwater dwindles, the hard engineering legacy that once powered the Mekong Delta’s agricultural boom is now undermining its resilience.
Back to nature?
Recognising the Mekong Delta’s importance, the Vietnamese government made it a national priority with the launch of Resolution 120 in 2017. It signalled a shift away from controlling water through infrastructure, to a “thuan thien” (nature-based) approach.
“It was groundbreaking, marking the end of the freshwater-centric development era,” said Dương Văn Ni, an agriculture and biodiversity expert focused on the Mekong Delta. Under the new vision, saltwater, floodwater and brackish water were no longer seen as threats to be minimised, but as resources to be managed. Rice, once the Delta’s agricultural backbone, was downgraded to third in priority, after aquaculture and fruit production.
The Mekong Delta Regional Plan for 2021-2030, published in 2022, reaffirmed this new direction.
Spiralling (back) into hard infrastructure?
Yet since the regional plan’s publication, experts worry the Delta has been heading in the opposite direction.
Most of the national agricultural budget still goes to large-scale water-control projects such as sea dikes and sluice gates, noted Lê Anh Tuấn. About 80% of government agricultural investment goes to irrigation and flood control, according to a 2022 Asian Development Bank report. Provinces, including Bến Tre, continue to push for more funding to expand this infrastructure. “Funds for crop restructuring and livelihood diversification remain small,” Lê added.
Even internationally funded projects reflect this trend. The eight-sluice-gate irrigation system backed by JICA – which Tân Phú and Bến Rớ are part of – has faced delays and suspensions due to cost overruns and currency fluctuations, leaving the project incomplete. The two sluice gates were completed in 2024 after seven years of construction delays.
What’s more, projects labelled as “livelihood” or “nature-based” often fall back into the old infrastructure trap. “My research reveals that […] emergent plans and projects – even those labelled nature-based – risk reproducing infrastructural side effects,” said Lizzie Yarina, whose work examined climate adaptation and infrastructure impacts in the Delta from 2020 to 2022.
She cited the World Bank’s Mekong Delta Integrated Climate Resilience and Sustainable Livelihoods project as an example. Despite its title, most of the USD 387 million budget was funnelled into dikes, sluices and roads, including parts of the Ba Lai system. The so-called “livelihood” elements often amounted to little more than fertiliser handouts, seedlings, or occasional training for farmers already practicing the methods being promoted, Yarina noted.
One reason for the continued push toward infrastructure, Yarina suggested, is visibility. “Everybody can see it. They can document it: ‘We built it’.” By contrast, investments in “soft” adaptation, like farmer training, crop diversification, or strengthening local governance, are much harder to measure and justify to funders.
The consequences of this infrastructure bias are mounting. “What we’ll leave behind for future generations is massive debt,” Lê Anh Tuấn said. Maintenance costs pile up, while the benefits – such as rice grown for export at low prices – don’t offset the real cost of the loans. “It’s like taking out a loan to buy a Mercedes, only to use it as a taxi,” he said. The ecological toll of past infrastructure projects – the loss of wildlife and degraded ecosystems – has also never been properly assessed, he added.
Looking forward
For Resolution 120 to fulfil its stated goals, experts say the focus must shift from engineering to livelihoods.
In coastal provinces, Dương Văn Ni has been attempting to prove that saltwater can also be a resource, not just a threat. He has developed a project in which farmers cultivate năn tượng – a native reed that thrives in saline soil and helps restore degraded land. This takes place largely on the shrimp ponds and rice fields of farmers who have either abandoned them due to low yield, or who have switched to the reed. The farmers supply the reed as raw material to over 3,000 craftspeople across the Delta, many of them women over 60 who live in rural areas.
“I want to show that the Resolution is possible,” Ni said. Such initiatives demonstrate that collaboration among farmers, scientists, businesses and local authorities can work, he added.
If infrastructure is used, it must be reimagined. “The real change must come from institutional reforms,” said Lê Anh Tuấn. Both he and Dương Văn Ni argue for small-scale, flexible solutions that evolve with changing conditions. Instead of vast reservoirs that evaporate quickly or become salinised, Tuấn advocates for small freshwater ponds and ditches, which he says better support communities during droughts.
The fixation on costly mega-projects risks undermining the very resilience the Mekong Delta urgently needs. Phương, the rice farmer, still hasn’t paid off the debt from the 2020 drought, and her land becomes more depleted with each season. “The rice barely sprouts, it’s no longer lush. The soil’s been contaminated [with salt],” she said. Phương now works part-time at a fruit processing plant just to stay afloat. Kêu, the rambutan grower, said that if seawater keeps creeping in, the community will “have to cut down our orchards and start over – or give up entirely”.
Yarina added: “One thing I hear again and again from people here is that they can adapt to economic or environmental uncertainty – they’ve done it for generations. What’s harder to adapt to is development uncertainty. Big projects disrupt water flows, displace communities and often ignore local knowledge in the process.”
