Swan River

Ephemeral river of southwestern Western Australia. It rises in the hills south of Corrigin as the Avon and flows 224 mi (360 km) northwest and southwest past Northam and Perth to the Indian Ocean at Fremantle. It is known as the Swan only along its lower 60-mi course. The rivers Helena (site of Mundaring Weir) and Canning are left-bank tributaries. Dry during much of the summer and