Vamanapuram River is an long river in southern Kerala. The river originates in the Chemunjimotta hills (alt. 1860m) hills on the southern side of the Western Ghats, and flows through Thiruvananthapuram district of Kerala. It ends in Anjengo Lake (Anchuthengu Lake) near Attingal otherwise known as Kollampuzhayaru and Attingalaru.The two tributaries of this river are the Upper Chittar & Manjaprayar streams.