Chaliyar, Bharathapuzha, Periyar and Pamba are the four medium rivers of Kerala, measuring 169, 209, 244 and 176 km

Background

Kerala has 44 perennial rivers, of which three flow eastward and 41 drain into the Lakshadweep Sea.
The four medium rivers are Chaliyar, Bharathapuzha, Periyar and Pamba.
Their lengths are 169 km, 209 km, 244 km and 176 km respectively.
Their total drainage area is only 8250 km2.
The remaining rivers range from 16 km to 130 km in length, with an average of 62 km.
About 30 reservoirs, mostly in the highlands, modulate the river flow.
The rivers have steep gradients and swift flow, lack delta formation and mainly follow a dendritic drainage pattern.