BANGKOK (AP) — The Mekong River has recently acquired an aquamarine colour that may beguile tourists but also indicates a problem caused by upstream dams, experts in Thailand said.
The river usually has a yellowish-brown shade due to the sediment it normally carries downstream. But lately it has been running clear, taking on a blue-green hue that is a reflection of the sky. The water levels have also become unusually low, exposing sandbanks that allow the curious to stand in the middle of the river.
Low water levels pose an obvious problem for fishermen and farmers, but experts said the decline in sediment exposes a different danger that can result in greater erosion of the river’s banks and bed.
The experts and people living along the river blame a large hydroelectric dam upstream in Laos that began operating in October for contributing to both problems, though rainfall has also been sparse.
Around 70 million people depend on the Mekong River for water, food, commerce, irrigation and transportation. Critics charge that large-scale development projects such as the Xayaburi dam dangerously disrupt the region’s ecology.
The dam blocks much sediment from moving further downstream, which accounts for the water becoming clear, said Pravit Kanthaduang, chief of the fishery office at Bueng Khong Long, a district in Thailand’s Bueng Kan province.
Less sediment means less nutrition for plants and fish in the river, threatening the ecological balance, he said.