Bhavanisagar Dam or Lower Bhavani Dam, is located in Erode district, Tamil Nadu, India. The dam is constructed on the Bhavani river. It is one of the world's largest earthen dams. The dam is situated some west of Sathyamangalam, is 17 km (11 mi) North of Punjai Puliampatti, is from Gobichettipalayam and is north-east to Mettupalayam.
The Lower Bhavani Project was the first major irrigation project initiated in India, after independence, in 1948. It was completed by 1955 and opened for use in 1956. The dam was constructed at a cost of .
The dam is long by high. The full reservoir level is and the dam has a capacity of .
Bhavanisagar dam is constructed on the Bhavani River. The dam receives water from two main catchment areas in the Western Ghats. The water is fed into the Bhavani river known as Upper Bhavani. The eastern catchment area includes the Upper Bhavani, Avalanche and Emerald lakes, Kundha, Gedhai, Pillur and Nellithurai . The western catchment area includes Portimund, Parson's valley, Pykara, Glenmorgan, Chinkara, Maravakandy, Moyar and Thengumarahatta. The dam is fed by both Southwest and Northeast monsoons.
The dam feeds water into two canals, Lower Bhavani Project Canal and Kalingarayan Canal. The Kalingarayan canal feeds Thadapalli and Arakkankottai channels and the LBP canal feeds the Thadapalli and Arakankottai channels.
The dam has two hydroelectric power stations, one on the east bank canal and the other on the Bhavani river. Each has a capacity of for a total capacity of .