The Banasura Sagar Dam, located 21 km from Kalpetta, is the largest earthen dam in India and the second largest in Asia. It is created by impounding the Karamanathodu tributary of the Kabini River. Construction was started in 1979, with the main objective being to support the Kakkayam Hydro-Electric Project, as well as to meet the irrigation and drinking water requirements of the people of the region.