Authorities admit shortcomings of system exposed by massive deluge.
BANGKOK CANNOT withstand more than 150 millimetres of rain, the Bangkok Metropolitan Administration (BMA) has admitted, adding that authorities were doing their best to drain floodwater.
Bangkok was last Saturday hit by the heaviest downpour in a decade – up to 214 millimetres in a single night – leaving many areas in the capital flooded and clogging traffic.
BMA deputy permanent secretary Sompong Wiangkaew said that BMA officers had done their best and the sewage system had operated properly during the storm, but the rain was just too heavy and the deluge was beyond their capacity to prevent floods.
“Our sewage system is designed for a rain amount of around 80 to 120 millimetres of rain and if the rain is more than 150 millimetres, it is inevitable for Bangkok to be flooded,” Sompong said.
Nevertheless, he said that even in the extreme case of last Saturday’s downpour, the BMA managed to drain floodwater from all major areas of the capital within 12 hours. This was much faster compared to the drainage ability of Bangkok a decade ago when some residents waited at least two days for floodwater to drain.
“What we did to mitigate the flood last Saturday was a big success and proved that our sewage system and giant water drainage tunnels work properly,” he said.
Asked if there will be an upgrade in Bangkok’s drainage system to prepare for more severe and unpredictable weather as a result of climate change, Sompong said that there was no need for the upgrade now as last weekend’s volume of downpour was rare and occurred only a few times in a decade.
In preparation for a high volume of water in the Chao Phraya River, he said that the BMA has been working closely with the Royal Irrigation Department (RID) to update and manage the water flow through the capital to make sure the river will |not burst its banks and flood the |city.
“We ensure that the water level in the river is at a safe level and under control, while the river embankment is also strong and properly maintained,” he said.
Meanwhile, National Council for Peace and Order (NCPO) deputy spokesperson Colonel Sirichan Ngathong revealed that General Chalermchai Sitthisart, NCPO secretary-general, ordered the army to help flood victims and assist relevant agencies to prevent and mitigate flooding.
Heavy rain slowly decreasing
Sirichan said that assistance from the army included medical support, transportation services, and flood relief aid distribution.
For the Bangkok area, she said that the NCPO has dispatched officers to help BMA maintain the pumping stations and assist BMA officers.
The military also worked with Metropolitan Police to mitigate traffic problems.
The Meteorological Department predicted that Bangkok will still face heavy rain on 60 to 70 per cent of the city until tomorrow, and then the chance of heavy rain over the capital will slowly decrease.
Meanwhile, storm Khanun has already weakened and will not have a direct effect on Thailand.