How does a major metropolitan city and its transportation systems deal with monsoon weather each year? You build a tunnel that can take the floodwater when it comes and then drain it out. The city of Kuala Lumpur did such an engineering feat and called it SMART Tunnel (Stormwater Management and Road Tunnel). Instead of losing hundreds of millions of dollars due to the flash floods that halt parts of the city, the SMART tunnel allows for citizens to get where they need to in the event of such weather.[see_also]
The tunnel itself is 13.2 meters (43 ft) in diameter and has three levels. The bottom level is solely utilized for water to drain through, and the upper two levels are for road traffic. In the event of a moderate storm, the middle level converts into a drainage for the excess water and when a severe storm comes, then all three levels take water that is diverted out. The SMART tunnel was constructed in 2007 and cost a little over half a billion dollars. It handles about 30,000 cars daily and has been utilized 44 times to divert the flood waters. Check out more information about the tunnel here.
via amusing planet