Korapuzha also known as Elathur River is a short river. It is formed by the confluence of two streams, Agalapuzha and Punnoorpuzha which originate in the mountains of Wayanad district. The Korapuzha empties into the Arabian Sea at Elathur. The river and its main trinutaries become tidal as they near the Arabian Sea. There is heavy boat traffic over the last 25 km (16 mi) of its course. It forms part of the West Coast Inland Navigation System. The Korapuzha is generally considered as the cordon sanitaire between the North Malabar and South Malabar in the erstwhile district of Malabar. Until the 20th century the Nair women of North Malabar crossing the Korapuzha and going south or marrying a person from South Malabar was considered a taboo and those who violated faced Bhrasht (Ostracism) and forfeiture of caste.

The river has two names - Chaliyar and Beypore puzha, of which the former is more popular. The river meets the Arabian Sea at an 'azhi' (estuary), the southern part of which is known as Chaliyam and northern part as Beypore. Thus the river gets the names Chaliyar and Chaliyar River. Chaliyar is one of the rivers which doesn't get dried up in the drought season. Many other rivers in Kerala get dried up during march and April. It flows through Malappuram District for most of its length and then for around 17 km it forms the boundary between Malappuram District and Kozhikode District before entering the city of Kozhikode for its final 10 km journey and finally empties into the Arabian Sea. Some of the Chaliyar's tributaries originate from Wayanad District and joins the main river in Malappuram. During late 19th century and early 20th century, the Chaliyar was extensively used as a waterway for carrying timber from the forest areas in and around Nilambur to the various mills in Kallai of Calicut city. Rafts made of logs were taken downstream during the monsoon season to Kallayi, where these were sawn to size in the timber mills dotting the banks of the river. Kallai was during this period one of the most important centers in the world for timber business. The place was famous for wood of superlative strength and durability like teak, rosewood, etc. Towards the second half of the 20th century, the activity came down drastically as tree felling was banned or strictly controlled with a view to stop deforestation. Many mills still operate in Kallai, though with far less output. Many have closed down.

• Korapuzha,Kallai and Chaliyar Rivers Map