The river drains into Gulf of Mannar near Punnaikayal in Tiruchendur taluk of Tuticorin district. The river drains with its tributaries an area of about . As most of its extensive catchment areas lie in the Western Ghats, the river enjoys the full benefit of both the monsoons, which make the river perennial. Since all its tributaries are arising from the Western ghats, the river is prone to heavy floods especially during the northeast monsoon. In 1992, there was an unexpected flood in Thamirabarani, which claimed hundreds of lives as the dam water was let out so massively and suddenly that the river and its channels could not bear the excess water inflow. It flooded again in 2015 with water entering the Kurukuthurai Murugan Temple.