According to Dr. Nguyen Thi Minh Phuong, DTU Dean of Environmental & Chemical Engineering, building submerged seawalls to shield Hoi An from strong waves will help reduce coastal erosion.
Dr. Nguyen Thi Minh Phuong
* Reporter: What are the main causes of the recent serious erosion in Cua Dai beach, one of the most attractive in the world?
Dr. Nguyen Thi Minh Phuong: According to the paper “Research into Hoi An’s coastal erosion”, published in 2017 by French researchers and Thuy Loi University in Hanoi, 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 is furthermore compounded by extreme weather conditions, increasing the severity of slope movement in the area.
* Reporter: How can further erosion be prevented?
Dr. Nguyen Thi Minh Phuong: Effective solutions on arresting beach erosion should be based on accurate environmental assessments on riverhead flow and the sand sediment process. Due to development, it is difficult to stop the construction of upstream hydro-power plants or bridges across the Thu Bon river. However, sand mining along the river can be reduced if the local authorities apply strict penalties to sustain coastal protection.
* Reporter: What is the risk of further erosion in this area?
Dr. Nguyen Thi Minh Phuong: In recent years, due to the impact of storms, high waves have impacted the shore horizontally. The seashore has suffered slope movement of up to 3 meters and powerful waves have increased slope movement far inland. The energy of these waves is so strong and the sand foundation now so weak that new seawalls will not be able to resist their continuing impact.
* Reporter: What do you think is the solution?
Dr. Nguyen Thi Minh Phuong: Hoi An must have an integrated, comprehensive plan based on coastal topography, wave flow and sand volume to completely resolve the problem. In other countries, shallow coral reefs do an excellent job of protecting the shore from major storms. 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 in the river.
* Reporter: Thank you!
(Media Center)