Explanation:

The rivers that originate in Western Ghats and flow towards west are Periyar,Bharathappuzha, Netravati, Sharavathi, Mandovi etc. The west flowing rivers of Western Ghats are fast moving, owing to the short distance travelled and steeper gradient. This makes Western Ghats more useful than Eastern Ghats in terms of production of hydroelectricity.Narmada and Tapti although don’t rise from Western Ghats but flow westwards.
The rivers that originate in Western Ghats and flow towards east include three major rivers viz. Godavari, Krishna and Kaveri, and many smaller / tributary rivers such as Tunga, Bhadra, Bhima, Malaprabha, Ghataprabha, Hemavathi, Kabini. These east flowing rivers are comparatively slower moving and eventually merge into larger rivers such as the Kaveri and Krishna.
The Thamirabarani or Tamraparni or Porunai is a perennial river that originates from the Agastyarkoodam peak of Pothigai hills of the Western Ghats. It flows through Tirunelveli and Tuticorin districts of the Tamil Nadu state of southern India into the Gulf of Mannar.