Officials have placed 300 sandbags to block water from entering the underpass tunnel in Bangkok's Prawet district where a businesswoman drowned last Thursday.
They are also trying to find possible leakage points in the wall of the tunnel or damage in a connected water-retention pond 10 metres away.
Last week, a rapid rise of water stalled a pickup truck passing through the underpass near the back entrance to the Golden Nakara housing estate. The 41-year-old driver who could not get out of her vehicle subsequently drowned.
Prawet district chief Thanasit Methaphanmueang said sandbags were placed to block water from a nearby trough in which the water level is now 1 metre high. The water was muddy, which meant it did not come from the rain, he said.
