The river is impounded by Lake Avon, the largest of the four reservoirs within the Upper Nepean Scheme that supplies potable water for greater metropolitan Sydney. Located near Bargo, approximately 100 kilometres (62 mi) south-west of Sydney,[2] construction of Avon Dam commenced in 1921 and was completed in 1927. In 1963, the water supply was diverted to meet the increasing needs of the Illawarra region and now supplies all the Wollongong area.[3]