How do MRT train stations reduce the risk of flooding?

Underground MRT stations are built with entrances (or exits) that are raised to safeguard them from flooding. Tenders for flood barriers to be built at MRT stations were called in 2012.
Christopher Tan, The Straits Times AsiaOne 25 Feb 17;

Like all underground structures here, MRT stations are built with entrances (or exits) that are raised. You will notice you need to climb a few steps before going down into a station. The same goes for road tunnels and underground carparks - a ramp is built just before the entrance and exit. This construction design safeguards the underground facility from flooding.

But in recent years, the weather has become more extreme. For example, on the afternoon of Dec 23, 2011, about 150mm of rain fell over Orchard Road - an amount usually received in a whole month. The incident damaged property along the shopping belt, including about 40 cars parked in underground carparks which became submerged.

In February 2012, the Land Transport Authority called tenders for flood barriers to be built at six MRT stations in town. In July 2012, tenders were called to fit similar barriers at 11 more stations deemed to be at risk. The barriers can withstand floodwaters of up to 1.5m high.

Today, flood barriers at 35 underground MRT stations have been completed across the network.

"With the completion of these works, all current and future MRT projects, including those on Downtown Line and Thomson-East Coast Line, will meet the requirements for flood protection as specified in PUB's Code of Practice for surface water drainage," the LTA said in a statement yesterday.

The attention to flood mitigation is a stark contrast to earlier pronouncements that Singapore was safe from the climate change effects.