The Canning Contour Channel is a 16 kilometres (9.9 mi) series of man-made concrete channels and steel and cast-iron pipelines in the Darling Scarp in Western Australia constructed between July 1935 and December 1936. The project was a Depression era public works scheme to carry potable water from just below Canning Dam through the hills around and above Roleystone and Kelmscott to a screening, fluoridation and pumping station near Gosnells by following the natural contours of the Canning Valley—hence it was entirely gravity-fed. Where a tributary valley needed to be crossed, suspended or siphoning pipelines were used. From Gosnells, the water entered the city's pipeline distribution system.