The provinces, Long An, An Giang, Dong Thap, Ben Tre, Soc Trang and Ca Mau, have either declared emergencies or cordoned off long stretches of land on the Mekong’s edge because of the erosion, the official Vietnam News Agency (VNA) reported.

“In Ca Mau Province, more than 25 kilometers (15.5 miles) of rivers need urgent measures,” VNA said of one of the affected areas, 250 kilometers (155 miles) southwest of Ho Chi Minh City, Vietnam’s main business hub.

“The eroded areas are especially dangerous, directly affecting residential areas, administrative areas, education and healthcare facilities,” the report said.

The 4,350 km (2,700-mile) river, known as the Lancang in its upper reaches, flows from China’s Tibetan Plateau along the borders of Myanmar, Laos and Thailand, through Cambodia and finally Vietnam, where it forms the delta known in Vietnam as the “Nine Dragons”.

In January, Reuters visited three provinces straddling different branches of the delta where local authorities had been struggling to slow the rapid pace of erosion in a region which has supported farming and fishing communities for millennia.

In addition to climate change, a key cause is years of upstream damming in Cambodia, Laos and China that prevents crucial sediment from reaching the lower reaches of the river.

That sediment, vital for checking the Mekong’s currents, has also been lost due to an insatiable demand for sand - a key ingredient in concrete and other construction materials - that has created a market both at home and abroad for unregulated mining of the river.

In July, the depth of the Mekong marking the border between Laos and northeastern Thailand fell to below 1.5 meters - compared to an average depth of 8 meters for that time of year - because of drought and upstream damming.

Authorities in Vietnam’s Ca Mau province have petitioned the government for an extra 74 billion dong ($3.19 million) in funding for urgent projects needed to protect the province’s western sea dyke, the VNA report said.

One area in the province is losing 80-100 meters of land annually to the erosion, VNA said, including an area of protective forest which would otherwise hold back incoming water.

By James Pearson - Reuters - September 24, 2019