Provincial experts said that by 2020, flooding in these low-lying coastal areas will submerge over 306sq.km.

Hoi An will be hit hardest, with flooding predicted in more than 26% of the city, followed by Dien Ban District with 26%, Duy Xuyen District with 16% and Nui Thanh District with 15%.

In Nui Thanh's Tam Hai island commune, seawater has encroached by 50m in the last five years. Local authorities plan to relocate approximately 200 households from the most severely affected village, Thuan An. Many villagers have already moved to the mainland, fearing the impact of more frequent natural disasters, said Nguyen Tan Hung, a commune official in charge of agriculture.

Since 2km of protective dykes were built along the coast in Tam Hai commune in 2012, landslides had decreased, Hung added.
 

However, a 30m section of the embankment was damaged in a storm in 2013 and the commune needed to expand the dyke system by 2.4 km in Thuan An and Binh Trung villages, where sea levels had been eroding by nearly 10m each year.

Rising sea levels and erosion were also affecting Cua Dai beach in Hoi An, home to many high-end resorts. The sea was now only 40m away from roads; tides had eroded the coast to such an extent that some beaches had been swept away completely.

Rising sea levels and erosion had hurt business at SunRise Resort, affecting more than 200m of beach in the last eight years and forcing the resort to spend US$1 million to build embankments, said resort director Ngo Van Hoang. However, the embankments could not withstand the high waves.

Several resorts invited experts from the Netherlands to survey the area and propose solutions, but the construction of a complex dyke system was beyond their means.

In 2010 the province approved a VND299 billion (US$14.2 million) project to build dykes along Hoi An's coast. However, only 714m of dykes have been built.