Silt: phù sa
Sediment: trầm tích (hạt ở dưới lòng sông)
“Previously, amount of sediment from the Mekong River to the Mekong Delta was about 73 million m3 [cubic meters] per year,” Nguyen said. “In 2012, only 42 million m3. It is forecast that when 19 under-construction hydropower reservoirs are completed, the amount of sediment in the Mekong River Delta [will be] only about 10-15 million m3.”
The lack of silt contributes to coastal erosion and – perhaps even more frightening – land infertility. Silt replenishes and enriches the Mekong Delta, which currently accounts for 90% of the country’s rice production and 50% of the food supply. Vietnam’s population will eventually be at risk if nutrient-dense silt deposits continue to decrease. Furthermore, as the dams prevent critical floodwaters from irrigating the fields, millions of wells are drying up the groundwater at an alarming rate. In 2016, farmers in the delta saw the worst drought in 100 years.