Coimbatore lies at in south India at 411 metres (1349 ft) above sea level on the banks of the Noyyal River, in northwestern Tamil Nadu. It covers an area of . It is surrounded by the Western Ghats mountain range to the west and the north, with reserve forests of the Nilgiri Biosphere Reserve on the northern side. The Noyyal River forms the southern boundary of the city, which has an extensive tank system fed by the river and rainwater. The eight major tanks and wetland areas of Coimbatore are namely, Singanallur, Valankulam, Ukkadam Periyakulam, Selvampathy, Narasampathi, Krishnampathi, Selvachinthamani, and Kumaraswami. Multiple streams drain the waste water from the city.