Sand mining in the Lower Mekong region is taking place at a far greater rate than previously reported, with an estimated 100 million metric tons (100 billion kilograms or 200 billion pounds) of sand extracted each year from Cambodia and Vietnam, experts said.
Sand mining is “a pervasive activity across much of the Lower Mekong that is widespread … and yet it’s fairly unconstrained and unquantified,” Christopher Hackney, a fellow at Newcastle University, said Monday during an online seminar hosted by the Washington-based Stimson Center.
According to a scientific report published in 2013, around 56 million tons of sediment were extracted in 2011 in the Lower Mekong region, including 32 million tons from Cambodia, 12 million tons from Vietnam, and 7 million tons from Laos.
The figure is still considered low due to underreporting by miners and weak government monitoring capabilities. It also did not cover extraction on Mekong tributaries.
“Development in Vietnam and Cambodia has grown [since 2013]. Demand for aggregates has grown,” said Hackney, who is mapping sand mining activities alongside Magdalena Smigaj, a postdoctoral researcher at Wageningen University.
By 2020, the volumes from Cambodia alone exceeded the 2013 estimate for the entire Mekong basin, with 59 million tons extracted a year, he said. It does not include the 32 million tons of sand city developers said is needed to fill a reclamation project in Phnom Penh.
The duo, using satellite imagery and deep learning, did not calculate figures for other countries, though some studies in the last year have estimated sand extraction in Vietnam to be around 49 million to 50 million tons.
“So combining those two [we] would come out with an estimate of about 100 million tons. That’s excluding Laos and further upstream,” Hackney said.
In one of the hotspots in Cambodia, the researchers noticed the number of sand-carrying vessels increasing from around 50 per month in 2016 to 150 a month in 2020.
Similarly, in Vietnam’s Dong Thap province, the duo noticed a sudden increase in traffic intensity in 2020, which then dropped in 2021.
Smigaj said it was primarily due to a boom in unregulated mining since ground monitoring was nil during the country’s strict COVID-19 lockdown.
The experts estimated around 10 times the natural supply of sand is being extracted from the riverbed in Cambodia alone.
“That sounds to me like a big problem,” said Brian Eyler, Southeast Asia program director at the Stimson Center.
“Sand mining hurts the river system,” he said, adding that it is “happening at an under-reported and mostly unregulated rate, in a way that is robbing or taking a very important component of the river’s mightiness out for other uses.”
By net weight, Cambodia was the 12th largest exporter of sand in 2021, according to the U.N. Comtrade database. It exported 797,218 metric tons that year.
Export data for Vietnam and Laos were not available, while Malaysia was the highest sand exporter, with 19.6 million metric tons annually.
Worldwide, 50 billion tons each year
Sand, an essential component of many construction materials, including concrete, asphalt, and glass, is the most mined material globally. It is essential for river systems, but excessive extraction has caused negative environmental impacts, including erosion, loss of biodiversity, and water pollution.
According to the United Nations Environment Programme, usage of sand resources has tripled worldwide in the last two decades, with about 50 billion tons of sand extracted from rivers, lakes, deltas, and coasts each year, and is expected to grow.
The world’s large rivers, including the Mekong, face reduced deposit loads due to activities like hydropower development and sediment extraction.
Hackney said climate change has exacerbated the problem, with changing weather and rainfall patterns shifting away from parts of the Mekong that generate sediment.
The Mekong is one of the world’s largest and most biodiverse river basins. More than 70 million people from five Southeast Asian countries depend on it for their livelihoods, primarily through fishing and agriculture.
Locals and government officials say sand dredging and China’s opening and closing of upstream dams have caused significant issues, including erosion, along the Mekong.
Experts estimate sand mining alone has caused the riverbed to erode up to 15 centimeters (6 inches) each year, resulting in increased tidewater extent and velocity that surges inland. There has also been a rise in salinity intrusion, a significant concern for the region’s “food basket,” with two million hectares at risk each year.
“On top of that, you’re destroying benthic habitats,” Hackney said, referring to animals and plants that live at the water bottom. “You’re removing the kind of feeding grounds for a lot of the invertebrates and biodiversity within the river system.”
Such deposit extraction also digs up fish breeding grounds and makes water cloudier, reducing light filtration and changing its chemistry and quality, he added.
“So yeah, the impacts are quite wide-ranging once you kind of unpick all the different aspects of the industry,” Hackney said.
In 2020, the Mekong River Commission, an intergovernmental body that helps coordinate river management, issued a basin development strategy to respond to increasing environmental and social pressures from climate change and development. It includes maintaining good flows and water quality and implementing a basin-wide sediment management plan.
“Sediment concentrations in the mainstream are observed to be much reduced largely as a consequence of sediment trapping and sand mining,” Anoulak Kittikhoun, Chief Executive Officer at the Mekong River Commission Secretariat, said in a speech last year.
He said suspended sediment concentration decreased up to 80% in some areas between 2018 and 2020.
“The trend is unmistakable,” he said, adding that sediment reduction has implications for floodplain productivity and riverbank stability.