Solution:

Bharatappuzha

• The Bharatappuzha also known as Nila, is a river in Kerala, with a length of 209 km.
• It is the second longest river in Kerala, after the Periyar river. It orginates in the Anamalai Hills in the western Ghats, and flows westward through palakkad Gap, across Palakkad,Thrissur and Malappuram districts.
• At Parali both Kannadipuzha and Kalpathipuzha merge and folw as Bharatappuzha and follows a westerly course untill it empties into the Arabian Sea at Ponnai.
• The Bharatappuzha is extensively dammed and there are 11 resorvoirs along the course of the river.
• Muthirapuzha is the tributery of Periyar.