VietNamNet Bridge – HCM City authorities aim to prevent flooding in six out of 11 areas in the city but work has been completed at only one site, according to the city’s Transport Department.
Most of the existing anti-flooding works in HCM City, which were built 10-20 years ago, have limited drainage capacity.
The third-class culverts of the city’s drainage system are designed to deal with rainfall of no more than 75.88 mm within three hours, while second-class culverts can deal with 85.36 mm and first-class canals 95.91 mm.
The rain on the afternoon of September 6 with water flow of 100 mm per hour on average and 122.3 mm per hour at its heaviest put a number of streets underwater.
Meanwhile, scientists have warned that in the future, as a result of climate change, HCM City will see heavier rains with water flow far beyond the designed capacity of the anti-flooding works.
Dr. Ho Long Phi from the HCM City National University noted that rains tend to be heavier recently. In the past, the rains only had a water flow of 60-70 mm per hour, while it is now 100-120 mm hour, or even higher.
“Rain with high frequency and high water flow makes it difficult to design anti-flooding works,” Phi said, adding that many of these works had become out of date because they were designed on old statistics.
Also according to the expert, the drainage system in the city is sufficient for a city of 2.5 million people, but HCM City has around 10 million.
In the inner city, the water drainage system was designed for an area of 100 square meters, while the total urban area has reached 600 square meters.
However, with limited capital, city authorities can only spend money on anti-flooding works to be built in several places.
In 2008, the city’s anti-flooding project capitalized at VND11,531 billion was approved by the Prime Minister.
However, the implementation of the project has been going at a snail’s pace because of lack of capital.
The implementation of other projects, including the second phase of the water drainage and pollution settlement at Tham Luong – Ben Cat – Nuoc Len Canal, has also been proceeding very slowly.
Another project, also approved by the government, which focuses on dealing with waste water in the inner area of the city, kicked off in 2003. It has made no headway.
The project on preventing tidal flows from Soai Rap to protect HCM City from high tides has not begun.
Thanh Mai