The Aura River (Finnish Aurajoki; Swedish Aura å) is a river in south-western Finland. Its sources are in Oripää, and it flows through Pöytyä, Aura and Lieto before discharging into the Archipelago Sea in the middle of the city of Turku. The waters of the Aura river are brown. The total length of the river is about 70 kilometres (43 mi), and it contains eleven rapids, the biggest of which is Nautelankoski at Lieto. The reserve tap water for Turku Region is drawn from the Aura, the city's secondary waterworks being situated by the Halinen rapids.