Niranam was an ancient sea port at the confluence of Manimala River and Pamba River. At Kaviyoor ancient rock-cut cave temples can still be seen.
Manimala River has been an important water way of Central Travancore. Rising in the hills of Kottayam-Idukki ranges, running westward, the river joins the plains at Manimala junction and then the flows through the midland plains and through the Kuttanad rice bowl area. Sand-mining on the river bed has led to depletion of the water ways of the river.