Long before the surveyors arrived, the Boonwurrung and Wurundjeri peoples of the Kulin nation lived along this water, and had done so for at least forty thousand years. The Birrarung was a larder and a meeting place. Along its banks and tributaries, clans gathered for corroborees, the ceremonial meetings that bound communities together. Eel and fish moved through its reaches; the floodplains gave up roots and game. For all those millennia the river ran clear. The brown that defines it now is a recent stain. When you stand at Birrarung Marr today, the riverside park whose name honours the original word, you are standing where that older Melbourne still quietly insists on being remembered.

In 1835, John Batman selected a site on the river's north bank and declared, "This will be the place for a village." The village became Melbourne, and the river became its working spine. The first port sat just downstream of the falls, where ships could draw saltwater on one side while the town drew drinking water from the other. It was a convenient arrangement that quickly turned grim. Early industries crowded the banks, and the same current that supplied water also carried away sewage and waste. By the 1850s the Yarra was foul enough to seed a typhoid epidemic that killed many. The city kept drinking and bathing in it anyway, until cleaner water was finally piped in from elsewhere.

The 19th century did not so much manage the Yarra as rebuild it. Gold-rush miners dammed and diverted whole stretches upstream, even blasting a 145-metre tunnel through solid rock at Pound Bend to expose the riverbed to their picks. Downstream, the demands of shipping reshaped the mouth entirely. Between 1880 and 1886, engineers cut the Coode Canal, straightening the river's lower course and leaving behind an artificial island named for the British engineer Sir John Coode. The Yarra Yarra falls, the very feature that had given the river its mistaken name, were dynamited in 1883 to let larger ships pass. The river that flows past the city today is in many places a human invention, dredged, diverted, and walled.

Melburnians call it the upside-down river, joking that it flows with the mud on top. The truth is less insulting than the legend: the brown comes from fine clay particles, washed in from easily eroded soils and kept aloft by the current's turbulence. When the water meets the marine salts of Port Phillip, the clay clumps together and sinks. It is a river that wears its catchment on its surface. Today the Birrarung is finding new advocates. Since 2004, the Yarra Riverkeeper Association has worked to give the river a voice in the city's decisions, and a 2017 plan formally recognised the Yarra and its lands as a single living entity, carrying its Wurundjeri name back into Victorian law.

For all the engineering, the upper Yarra remains wild. Its source is a cluster of swamps west of the Mount Baw Baw plateau, in forest so protected that only water-authority staff may enter. Fed there by snowmelt, it is the most westerly snow-fed river in Australia, running roughly 242 kilometres from subalpine forest, through the vineyards of the Yarra Valley, and into the heart of Melbourne before emptying into Port Phillip at the nation's busiest seaport. One river holds both extremes: untouched mountain ash forest at one end, container cranes at the other, and a city that is only now learning to call it by its first name.