According to Phi, if weather incidents that are similar to Bangkok occur in HCM City, the water level in Saigon River may rise to 1.7m or higher. Around 60,000 hectares in depressed areas like Binh Thanh, Nha Be, Thu Duc, Cu Chi, Binh Chanh, District 2, District 6, District 7 and District 8 will be threatened.
In the inner city, if rains of over 100mm come at the same time with flood-tide, prolonged flood on a vast area can happen.
However, the terrain of most of developed areas in HCM City is quite favorable for water drainage so if HCM City prepares well, losses can be mitigated, Phi said.
The expert also said that the city’s annual sinking is up to 2-3cm in some areas and there is no detailed research work of the reason. However, research works conducted in Jakarta, Bangkok and Shanghai show that underground water exploitation, high-rise buildings and weak foundation attribute to sinking.
In HCM City, poorly-controlled urban development in the last several decades has caused the overload and downgraded of the drainage system. Consequently, flood appeared in the late of 1990s. This situation is the same in other big cities in Vietnam like Hanoi, Da Nang, Can Tho and Da Lat.
The rise of sea level also makes the rise of river level. Other reasons consist of the poor administration of upstream reservoirs and deforestation.
According to Phi, flood in inner HCM City began to gradually reduce since 2007 but flood in the newly-developed area begins.
Phi is very worried with the function of upstream reservoirs like Tri An, Dau Tieng and Phuoc Hoa, which are located near HCM City, in reducing flood if storms occur in late rainy seasons in the upstream area.
Phi suggested to review flood control plans and work out measures to mitigate floods in HCM City. He emphasized the significance of these measures besides the construction of anti-flood works.
After the historical flood of three months long, Thailand will have to pay at least $3 billion for post-flood reconstruction while losses caused by flooding is around $5 billion. At least 381 people are reported dead so far while around 2.3 million others are affected by flood.
Around 113,000 people are living in 1,700 evacuation zones. The historical flood affects one third of provinces and three fourths of Thailand’s area, including 300,000 hectare of crops.