naming of various places in Adelaide. Pirltawardli, now within Park 1/Pitawardli, a location next to the river near the weir, on the western side of North Adelaide, is an area of great historical significance, as the location of a Kaurna camp and later the first Christian mission and school in South Australia. The missionaries documented the Kaurna language, which formed the basis of the 21st-century language revival of the language. The "native location" and school moved from the southern side of the river (now Bonython Park) to the northern side several times. Changes after 1836 During early years of colonisation, the surrounding trees were cut down and the river's gravel used in road making and construction of buildings. As the natural environment was removed, the banks were eroded and the riverbed gradually levelled as waterholes filled. By 1878 the river was noted to be a malodorous, black sewer rather than the sylvan stream of the 1830s. Much of the river's catchment area consists of cleared farmland with run-off captured in private dams to sustain farming over Adelaide's dry summer. Combined with the river's use for potable water this has greatly reduced the overall flow especially in the lower river. Flood mitigation A flood mitigation bill was passed in 1917 to not only combat the damage caused by floods but also the public health risk due to the lack of mains sewerage in the western suburbs. Popular opinion favoured diverting the flood waters into their "natural" outlets of the Port and Patawalonga Rivers. The chief engineer of the department of works favoured a cutting through sand dunes near Henley Beach, allowing the river an outlet, mitigating floods and preventing silting of the Port River. He also advocated the construction of a reservoir where the Kangaroo Creek Reservoir is now, to both mitigate floods and provide summer irrigation water for market gardens. Unfortunately the bill lapsed with no action as the government and local councils were unwilling to fund the works. The Millbrook Reservoir opened in 1918 as a summer water source, and flood mitigator if required. A bill was passed in 1923 to enact the earlier plan of cutting through the dunes and adding an upstream regulating weir. Again the bill lapsed due to a lack of commitment from parties on payment. A major flood in 1931 and another in 1933 led to the latest in a series of government enquiries.