It is surrounded by the Western Ghats mountain range on the West and North, with reserve forests and the (Nilgiri Biosphere Reserve) on the northern side. The Noyyal River runs through Coimbatore and forms the southern boundary of the corporation. The city sits amidst Noyyal's basin area and has an extensive tank system fed by the river and rainwater. The eight major tanks / wetland areas of Coimbatore are Singanallur, Valankulam, Ukkadam Periyakulam, Selvampathy, Narasampathi, Krishnampathi, Selvachinthamani and Kumaraswami tanks. Sanganur pallam, Kovilmedu pallam, Vilankurichi-Singanallur Pallam, Karperayan Koil pallam, Railway feeder roadside drain, Trichy-Singanallur Check drain and Sanganoor pallam are some of the streams that drain the city.