The Bharathappuzha, also known as the Nila River or Ponnani River, is a river in the Indian states of Tamil Nadu and Kerala. With a length of 209 km, it is the second longest river that flows through Kerala after the Periyar. It flows through the Palakkad Gap, which is also the largest opening in the Kerala portion of the Western Ghats. The Nila has gro…The Bharathappuzha, also known as the Nila River or Ponnani River, is a river in the Indian states of Tamil Nadu and Kerala. With a length of 209 km, it is the second longest river that flows through Kerala after the Periyar. It flows through the Palakkad Gap, which is also the largest opening in the Kerala portion of the Western Ghats. The Nila has groomed the culture and life of South Malabar part of Kerala. It is also referred to as the "Peraar" in ancient scripts and documents. River Bharathapuzha is an interstate river and lifeline water source for a population residing in four administrative districts, namely Malappuram and Palakkad districts, and parts of Palakkad-Thrissur district border of Kerala and Coimbatore, and Tiruppur of Tamil Nadu. The fertile Thrissur-Ponnani Kole Wetlands lie on its bank.