Bangkok, Sep 16 (ANI): Bangkok, the cultural, political and economic capital of Thailand is a growing metropolis. It is located on the flat and low-lying area of the Chao Phraya river, with an average elevation of 1.5 meters above sea level. Most of the area was originally swamp land, which was gradually drained and irrigated by the construction of canals, between sixteenth and nineteenth centuries. Flood control during the rainy season is one of the most important challenges in Bangkok. The city has vast network of canals, but its draining ability is limited and unsustainable when it rains heavily. In order to cope with floods, the Bangkok Metropolitan Administration constructed a drainage underground tunnel by connecting the Makkasan Pond to and three canals in the city, to a pump station at the Chao Phraya river. This is the water intake building at Makkasan Pond.