The main rivers of Tamil Nadu originate in the Western Ghats and flow eastward. All of them are rain fed. The state has a few perennial rivers, apart from Kaveri. They are Palar, Cheyyar, Ponniyar, Meyar, Bhavani, Amaravati, Vaigai, Chittar and Thamirabarani. The non-perennial rivers are the Vellar, Noyil, Suruli, Gundar, Vaipar, Valparai and Varshali. Kaveri is the largest river of the state with a length of 760-kms.