Nhadautu.vn has published an article on how An Bang beach in Hoi An suffered from severe slope movement and erosion after the recent Vamco tornado.
Dr. Nguyen Thi Minh Phuong, DTU Dean of Environmental & Chemical Engineering, explains in her paper “Research into Hoi An’s coastal erosion” that the main causes are the massive upstream hydroelectric construction projects blocking sediment supply, extensive sand mining on the Thu Bon river and bridge construction obstructing and diverting water flow.
The problem of sediment deficiency at the beaches was furthermore compounded by recent extreme weather, increasing the severity of slope movement in the area.
“Due to the impact of the storms, high waves hit the shore at a straight angle,” Dr. Minh Phuong explained. “The seashore suffered slope movement of up to 3 meters and powerful waves beating this section increased slope movement deep inland. The energy of these waves is so strong and the sediment foundation now so weak that new seawalls will not be able to resist their continuing impact.”
Quang Nam must construct new submerged seawalls
Dr. Minh Phuong stated that Hoi An must have an integrated comprehensive plan based on coastal topography, wave flow, and sediment quantity to completely solve the problem. In other countries, shallow coral reefs do an excellent job of protecting the shore from major storms.
This shows that Quang Nam can learn from nature to reduce the strength of the waves long before they hit the shore, with submerged barriers similar to coral reefs. If the waves are obstructed at a distance, their energy will then be significantly dissipated.
Dr. Minh Phuong suggested that: “Submerged barriers could be constructed from four-pin concrete blocks, like the ones at Tinh beach in the Nui Thanh district of Quang Nam. This solution must be coupled with building restrictions upstream and a complete ban on sand mining on the Thu Bon River for sustainable coastal protection.”
Damage at An Bang beach in Hoi An
Mr. Nguyen The Hung, the Hoi An People’s Committee Chairman, explained that the provincial and local authorities are planning a project to overcome the effects of slope movement and are researching ideas on how to proceed.
This intermediate project would be financed with 300 billion vnd from the national government and 1 trillion from France, with a completion date of September 2021.
The Quang Nam province People’s Committee has meanwhile been working on a long-term solution. Individual local authorities will plan and construct their own means of protection, also by September 2021. Quang Nam province is also planning to strengthen the foundations of beachfront hotels and restaurants.
The Quang Nam province People’s Committee Vice-Chairman also remarked that new sandbanks around Cua Dai are impeding the passage of marine craft and has already petitioned the Ministry of Transport to commence a dredging project and, at the same time, provide extra sand for the areas most affected by erosion.
(Media Center)