Bhavani River is a major river in Kongu Nadu region of Tamil Nadu, India. It is the second longest river in Tamil Nadu. This river is a major tributary of the Kaveri River. Bhavani river originates(starts) from Nilgiri hills of the Western Ghats. Bhavani enters the Silent Valley National Park in Kerala. It flows back towards Tamil Nadu. The Bhavani is a 217-kilometre (135 mi) long perennial(everlasting) river. The river drains an area of 0.62 million hectares (2,400 sq mi) spread over Tamil Nadu (87%), Kerala (9%) and Karnataka (4%). About 90 per cent of the river's water is used for agriculture irrigation.
Bhavanisagar dam is located on the Bhavani river in Erode district, Tamil Nadu, India. The dam is one of the largest earthen dams in the world. The dam is 8 km (5.0 mi) long and 40 m (130 ft) high. The full reservoir level is 120 ft (37 m) . The dam has a capacity of 32.8×109 cu ft (930×106 m3). Kodiveri dam is also located on the Bhavani River near Gobichettipalayam in Western Tamil Nadu.