The Maribyrnong Valley, north-west of Melbourne, lies along the Maribyrnong River and diverges into the river’s tributaries at Keilor. It is a relatively small part of the Maribyrnong River catchment.
The origins of the catchment streams are, working from west to north: Jacksons Creek and Riddell Creek (Macedon Ranges); Emu Creek (Romsey); and Deep Creek (Lancefield). Jacksons and Deep Creeks converge at Bulla, west of the Melbourne Airport, whereupon the resulting single stream becomes the Maribyrnong River.
The river joins the Yarra River about 3 km from the latter’s entry into Port Phillip Bay. Depending upon river-flow and tidal conditions salt water can flow 12 km up the Maribyrnong River. The name of the river is thought by some authorities to have been derived from an Aboriginal word meaning salt water, and the river was known by the name Saltwater until 1913. An alternative interpretation is that the name was an Aboriginal expression concerning the sound of a possum.
The Maribyrnong Valley can be viewed at Brimbank Park, Keilor, or near a railway trestle bridge adjacent to the Western Ring Road, or at Avondale Heights. The valley continues beyond there, rounding the site of the former Maribyrnong explosives factory and passing below the Highpoint shopping centre.
At about there the river enters a flood plain, instanced by past floodings of the Flemington Racecourse on its eastern bank. Back at the railway bridge, though, the valley is 60 metres deep, and the valley slopes are 30 degrees or more.
Industrial uses once plagued the lower Maribyrnong Valley – abattoirs, bone works, wool scouring and such like. North of the Maribyrnong Road bridge over the river the water was safer for angling, rowing and river-side resorts, and residents of Ascot Vale and Essendon continue to use the river extensively for recreation. A river-side tea garden was further upstream, near Canning Street. These historic recreation patterns to some extent inspired the creation of linear parks along the river from Footscray to Avondale Heights during the 1980s-90s.
During the 1990s-2000s several of the explosives and munitions sites along the river were developed for housing. Several heritage structures were retained, notably Jacks explosives magazine (1878), near the equally historic Pipemakers Park. About 2 km downstream there is a remnant of the once busy Footscray wharves.
Hugh Anderson, Saltwater River trails: Sunbury to the sea, Red Rooster Press, 1984
Judy Maddigan and Lenore Frost, Maribyrnong record: past images of the river, Essendon Historical Society, 1995