6.6   Drainage

. Drainage Rivers of Tamil Nadu are its lifeline. Though it has many rivers, the rivers of Cauvery, Palar, Ponnaiyar, Vaigai and Thamirabarani are the notable ones. Most of the rivers of Tamil Nadu originate from Western Ghats and flow towards east and drain into the Bay of Bengal. All the rivers of the state are non-perennial except Thamirabarani. It is perennial as it is fed by both the southwest and northeast monsoons. Cauvery The river Cauvery originates at Talacauvery in the Brahmagiri hills of Kodagu(coorg) district of Karnataka in the Western Ghats. Total length of Cauvery river is km. About km of its course falls in Tamil Nadu. It serves as the boundary between Karnataka and Tamil Nadu for a distance of km. It forms Hogenakkal waterfalls in Dharmapuri district. Mettur Dam, also called Pachaimalai It is the lowest hill range, spreads over the districts of Perambalur, Tiruchirapalli and Salem. In Tamil language, pachai means green. The vegetation in this range is greener than the vegetative cover of the other hills in this region. Hence, it is named as ‘ Pachaimalai ’. Jackfruit is a popular seasonal agricultural product of this hills.