Subsidence, erosion and rising sea levels are among problems that the delta has to deal with currently, Minister of Natural Resources and Environment Tran Hong Ha said at a conference held Tuesday in HCMC that sought development solutions for the region.

"Climate change is evolving [in the Mekong Delta] much faster than the predicted scenarios. We need to re-evaluate how coastal and riverbank erosion is taking place and find suitable solutions," he said.

Ha noted that two years ago, Prime Minister Nguyen Xuan Phuc had stressed the need for the region to adapt to the challenges facing it. The PM had said that Vietnam's rice basket and also the source of most of the nation’s seafood exports, should "get along with climate change and natural conditions in its path of sustainable development."

The delta, which spans 3.94 million hectares (9.7 acres), is home to 17.5 million people or a fifth of the country's population.

Hoang Van Bay, head of the ministry’s Department of Water Resources Management, said that by last year, the delta had suffered erosion in 562 coastal and river bank areas measuring a total of 790 km (490 miles) in length.

The erosion is not only happening during the rainy season, but also the dry season, both at major river branches and canal systems, with a much higher frequency than in the past, he said. The areas that have suffered most from erosion are the provinces of Ca Mau, Soc Trang, Tra Vinh, Ben Tre and Tien Giang.

The Advisory Council to the National Committee on Climate Change had said in 2016 that if the sea level rises by 100 centimeters, up to 40 percent of the Mekong Delta will be under water.

Hydropower impacts

Another long-standing problem facing the delta is salt intrusion. Apart from climate change impacts, this problem is caused by hydropower projects upstream the Mekong River, experts said at the conference.

They said that salt intrusion was not the only problem caused by the upstream dams, although it has led to water shortages and related negative impacts on both daily life and farming activities of local people.

The growth of hydropower plants could also take away as many as 90 percent of the alluvium that has enriched the Mekong Delta every flooding season for centuries, making it highly fertile.

The upstream dams retain mud and sand and along with that, the alluvium, said a report by the environment ministry.

"The Mekong Delta has been thriving thanks to alluvium and now that a significant amount of that resource has gone, the region’s development is under threat," said Minister Ha.

One solution to help the delta cope with the crisis, proposed by representatives of the World Bank, was that the region reduces the area for paddy cultivation and switch to other crops of high value and adaptability to climate change.