Still barefoot, he ran home as fast as he could, his glasses falling to the wayside.
He called his neighbors on the phone, telling them to dam their homes with whatever they could. At the time, he was only worried that the coming flood would sweep away some possessions in his home. He was wrong.
When he reached his house, the front garden was already completely underwater. His house was now at the edge of the river. The earth underneath the edges of his home was being swept away, rapidly disappearing into the water.
"I was so panicked," he said. "I only had time to take a bag with personal papers, my child’s birth certificate and my father’s altar picture, before I ran for dear life."
In another 10 minutes, the erosion had surrounded the house. As the ground fell apart, the house walls cracked, and the home, along with Thao’s business (over 1,000 potted orchids and a fruit orchard), slipped into what now looked like a rising sea.
"Everything’s gone. There’s nothing left. How will I live now?" Thao sobbed in a video footage showing the house’s last moments. His only consolation was that his family was safe. There had been no one inside the house at the time.
In the Mekong Delta, rivers have been gulping up large chunks of land over time. That day, An Binh Islet in Vinh Long Province lost over 41,500 m2 of land, including the homes of 30 families. Property damage was estimated to total VND35 billion ($1.46 million).
Erosion is far from a problem exclusive to Vinh Long. Over the last two decades, it has been eating away at the lives of millions of people across the Mekong Delta’s 12 provinces.
Across the rivers of the Delta, there are around 585 major erosion hot spots, spanning over 741 km. Eighty-seven locations, spanning 135 km, are considered extremely dangerous, capable of directly affecting residential areas and important infrastructure, even with some protection provided by dikes, according to the Vietnam Disaster and Dike Management Authority.
River erosion happens the most in upstream localities, like An Giang or Dong Thap, and transition areas impacted by tides and water flow, such as Can Tho, Tien Giang and Vinh Long, as well along the coast, in Ca Mau and Soc Trang.
Experts said erosion in the region has been escalating and was no longer considered natural starting 1992.
There are now more erosion points than ever before. Within the first six months of the year, the Mekong Delta has seen 145 cases of major erosion along its rivers and streams, more than the total number of cases for all of 2022. In An Giang, the number of erosion events within the first seven months has already totaled three times what it was in the same period of last year. Similarly, Bac Lieu recorded a number of erosion cases nearly twice what it was in previous years.
The lack of sand and illuvium is the root cause of erosion in the Delta, according to Marc Goichot, WWF Freshwater Lead Asia Pacific. Once there is not enough material to fill up holes in the bottom of riverbeds, erosion begins to make its way onto the riverbanks.
The vengeful river
The illuvium began to slip away when a series of hydropower plants in China and upstream Mekong localities opened in the 90s. The amount of fine illuvium downstream quickly dropped by around 50%, from 160 million tons a year (1992) to 85 million tons (2014), according to the Mekong River Commission (MRC). It has been forecast that when the 11 new hydropower plants planned for downstream are completed, the amount of fine illuvium will be cut in half again, from 85 to 42 million tons a year. By 2040, there will only be 4.5 million tons of illuvium left to reach the Mekong Delta, according to research.
That means an ever-increasing amount of erosion in most Delta localities. Areas along the Tien River, like An Giang, Dong Thap, or Tien Giang, will see more erosion than those on the Hau River area due to higher volumes of water flow.
While sands continue to flow less and less from upstream to downstream, the demand for them rises dramatically. When humans take the sands away, the rivers ask for them back in return, this time from the shores and riverbanks.
At around 9 p.m. on October 29, 2012, the alluvial ground in An Binh Commune, 10 km away from Thao's house, suddenly eroded. Around 8,000 m2 of land fell prey to the water, along with four ponds and 23 fish cages belonging to eight families.
"We lost everything after that," said Pham Thi Sau, 75, one of the victims.
Pham Thi Sau, 75, talks about the erosion that took away her house and fish pond in Vinh Long Province in 2012. Photo by VnExpress/Hoang Nam
She and her son were sitting near the alluvial ground, where hundreds of fish cages were lined up together, when the incident happened. Over 10 years have passed since, and Sau's family has eventually found their way back up on their feet.
Starting life from scratch is nothing new to the people of the Mekong Delta. In 2012, when disease swept through her longan garden, Sau and others like her borrowed VND100 million from the state to turn the alluvial ground at the Tien River into a fishpond. But just a week before the fish were supposed to go on sale, the erosion came. Some 4,000 m2 of pond, along with three tons of fish, were then gone.
Five months after the erosion, the Southern Institute of Water Resources Research said the cause of the erosion was sand extraction and dredging. An Binh Islet at the time was surrounded by sand mines, which continuously took sand from the river, day and night.
Research by the Institute after 2012 showed that without the sand extraction process, there would be very little erosion. Naturally, erosion have been happening at the rate of less than a meter a year on average, but topological surveys at the river's bottom revealed that there were areas lopsided by 2-7 meters. Areas where erosion happened were supposed to recover thanks to the sand that comes from upstream every year, but sand extraction has disrupted this process, creating holes in the bottom of the rivers.
"For there to be such deep holes, if we account for only the impact of water flow, it would take several years. However, holes as deep as 10 m have appeared within a short amount of time, meaning there must have been human intervention," said Le Thanh Chuong, director of the Research Center for River Governance and Disaster Prevention at the Institute.
"Erosion as a phenomenon has a causal relationship, in which the riverbed is the cause and the eroded bank is the effect," said Ha Huy Anh,
Project Manager of Sustainable Sand Management at WWF-Vietnam.
Recent research has revealed that the Mekong Delta is experiencing severe sediment imbalances, according to WWF-Vietnam. Every year, the amount of sand flowing to the Delta is around 6.8-7 million tons, while the amount of sand extracted is 28-40 million tons. Along with the 6.5 million tons of sand flowing to the sea every year, the Delta loses at least 27.5 million tons of sand each year.
Sandless river areas take a concave shape, causing changes to water levels in different river regions, altering water flow.
Right now, the Delta is home to over 80 businesses approved for sand extraction. They take away 28 million tons of the material a year. Coupled with illegal sand mining, the amount of sand lost is uncontrollable.
"The actual amount of sand mined is much higher, and without a management method, the disappearance of sand is inevitable," Nguyen Van Tien, deputy head of the Vietnam Disaster and Dyke Management Authority, told a 2022 conference on limiting sand mining.
While sands from upstream are needed to fill holes in the rivers, hydropower plants have kept sediment from flowing downstream, disrupting the process. The main river flow therefore takes away mud and sand from the bottom of rivers without replacing them, causing a chain reaction to impact other smaller river branches as well.
"That’s when erosion spreads across the entire Delta, even to small streams, where no sand mining took place," said Nguyen Huu Thien, an independent expert on the Mekong Delta.
Meanwhile, the lack of sediment also leaves estuaries vulnerable to coastal tides. The consequence is deep erosion along 400 km of Mekong Delta coastline.
The river gives and the river takes back
Following the erosion catastrophe in 2012, Sau and seven other families sued a group of sand mining companies, asking for compensation of over
VND130 million.
At the time, there had yet to be asphalt roads in place, so every time she was summoned, Sau had to traverse over 10 km back and forth to the location, either on foot or by asking for a ride. With the gardens and ponds gone, as well as the lengthy court process, her family went bankrupt. It took four years after the incident before the sand mining company agreed to compensate her with VND42.5 million.
But the erosion does not end there.
A survey revealed that a nearby river section spanning over 300 m has a high chance of being swept away as heavy erosion has already created a very steep bank. Authorities had to issue a ban on sand mining for the 18 km section of river from the My Thuan Bridge to the Dinh Khao Ferry. A similar survey is also being done throughout the entirety of the Tien River section running through Vinh Long to evaluate the sand mining situation.
"The flow brings sands and illuvium, creating the river. The river takes care of humans, but when humans affect the flow, the sediments and the sands, the river takes them back, sometimes even with human lives," said Nguyen Nghia Hung, deputy head of the Southern Institute of Water Resources Research.
Hung said every interaction between humans and rivers has a causal effect and incurs regional impacts. Any action that changes the river’s "natural body," like deforestation, dam construction and sand mining, will incur a price, he added.
Those who depend on the Mekong River the most are, unfortunately, the ones who pay the highest price for the faults that are not their own. They themselves are also the ones with the least control over the rivers.
After years of saving, Sau finally re-stabilized her life. She now has her own fish ponds, ready to be harvested.
"If everything goes well, a batch of fish every six months could net me hundreds of millions of Vietnamese dong as profit. Under the condition that there be no more sand mining," she said.
As for Thao’s old neighborhood, the area has become a river section full of water hyacinths and a fish farm for locals. Villagers from the eroded areas have mostly moved away, away from the river that had raised them in the past.
Hoang Nam, Thu Hang
*This story is the second part of a four-part series. Read the first part here. The third part, "Erosion puts Mekong Delta future in doubt," will be published on Sept. 7, 2023.
