VietNamNet Bridge – With increased land subsidence, HCM City needs to build dykes like the ones used in the Netherlands to prevent tides and floods, experts have urged.
HCM City Mayor Nguyen Thien Nhan said MONRE has surveyed the soil and terrain conditions at 17 points in HCMC. The monitoring shows continued subsidence at all points. Subsidence of up to 30 cm in the last 10 years has been found in two places.
“If the soil sinks by 1 cm per annum and the sea water level rises by 0.5 cm per annum, or 1.5 cm in total, the difference between the earth surface and sea water level would be up to 45 cm. If so, the problem will be very serious,” Nhan said.
“This will be a big challenge for the city in the next 50-60 years,” he said.
HCM city leaders said it is necessary to make big investments to build a dyke system for the whole city and for every riverside area. However, it would be very costly to build dykes, especially when the city needs huge capital for many other infrastructure works.
Nguyen Ngoc Cong, director of the HCM City Anti-flood Program’s management board, said the city began building dykes to prevent flood tides in 2001.
|HCM city leaders said it is necessary to make big investments to build a dyke system for the whole city and for every riverside area. However, it would be very costly to build dykes, especially when the city needs huge capital for many other infrastructure works.|
MARD had suggested building dykes from the city to Long An province. However, foreign consultancy firms said it would be better not to rush to build a system of dykes covering the entire south of the city (Districts 7 and Nha Be) because this was a tidal area.
If a dyke was built there, when the tide rises, there would be no way for water to disperse and the water level on the Sai Gon River would rise.
To date, nearly 70 kilometers of dykes out of 179 kilometers from Muong Chuoi to Ben Duoc have been built. Because of the limited budget, the city is focusing on building dykes at hot spots.
“The building of dykes is very necessary to prevent tides and floods. We have to build dykes like the ones in the Netherlands, though it is costly,” he said.
Also, according to Cong, the city is implementing a project on dealing with tides in HCM City with consideration of climate change, capitalized at VND10 trillion.
Under the project, an important system of dykes from Vam Thuat to Kinh river will be built.
It is estimated that the city will need another VND20 trillion to complete the system of dykes. The city is also planning to build 100 reservoirs.
Meanwhile, some experts commented that it is too costly and the dykes won’t help much because the major problem is soil subsidence, caused by rapid urbanization.