Karamana River is in Thiruvananthapuram district. This river originates from Agastyarkoodam on the Western Ghats and flows towards the west. It has a length of around 68 kms and then joins the Arabian Sea at Kovalam. Even though the river is not very lengthy there are two dams on it. The two dams are Peppara dam and the Aruvikkara dam. The Peppara dam is constructed for irrigational purposes whereas the Aruvikkara dam is meant for both drinking and irrigational purposes.

A famous tributary of Karamana River is Killiyar joining the main river from Pallathukadavu. This tributary originates from the Panavoor village. There are many bridges built across the river and the largest is the bridge at Karamana. Some other main bridges are Thrikkunnapuram, Mangattu Kadavu, Aruvikkara, Aryanad etc. The bridge near Malamukal is low and that navigation is impossible through this area. An important tourist destination called as Aruvikkara is on the banks of this river. The river is now polluted due to the disposal of wastes.