ćorkovac is an eastern confluent of the vrbanja river in bosnia. it begins on the north-eastern slopes of the vlašić mountain's plateau, and the mouth opens at šiprage, where the town's sawmill was. the spring of ćorkovac is 1,150 metres above sea level, and its length is around 6 kilometres. it flows between the jasen and stražbenica mountains to its estuary. the watermills were in operation until the 1960s.