Elathur River alias Korapuzha, the boundary between North Malabar and South Malabar is formed by the joining of the two streams Punnurpuzha and Agalapuzha. The Punnurpuzha, which forms a part of the important West Coast Inland Navigation System, originates from Arikkanakunnu and the Agalapuzha serves as a backwater. The total length of the Korapuzha river is 40 kms. with a drainage area of 624 sq.kms. It merges into the Arabian Sea at Elathur and in their lower reaches, the river and its main tributaries become tidal. Korapuzha is the venue of the Korapuzha Jalotsavam, the water sports festival held during the month of August.