The smart tunnel in Kuala Lumpur that saves the city from flooding

In the Malaysian capital, the city of Kuala Lumpur, there is a very remarkable engineering structure that plays an important role in the life of the city and even received a special UN engineering award. This is the SMART underground tunnel, whose name literally stands for "Stormwater Management And Road Tunnel". The name is fully consistent with its unique purpose, because the tunnel combines, it would seem, completely incompatible functions.

The Malaysian capital is located only 3 degrees north of the equator, we can say that it is almost the equator. The climate here is typical of such a location with heavy daily rainfall. Perhaps this would not be a problem if the city was on a hill or had not such a large area. But a large metropolis is located in a lowering relief, in a valley of two rivers. For this reason, storm sewer systems designed to drain excess moisture do not cope with their task in those periods when heavy rains fall on the city. The government of the country decided once and for all to solve the problem of flooding the center of Kuala Lumpur, and at the same time unload one of the highways, building a tunnel that is technically complex.

The length of the tunnel is 9.7 kilometers, it consists of two levels, so it can be operated in three different modes. When the city’s storm sewer manages without a SMART tunnel, it works only as an underground roadbed. If heavy rainfall begins in the city, engineers open the floodgates and water passes through the bypass tunnel at the lower level, under the freeway, but at the same time, SMART continues to function as a highway.

In the most emergency case, when the center of Kuala Lumpur is in danger of flooding, the tunnel is completely closed for vehicles, using all its capacity to drain storm water.