The only source of water for almost 400 convicts, marines and free settlers was six wooden barrels sunk in the sand to tap groundwater. Although settlement of the Port Phillip region had gradually grown after Collins arrived, it was not until 1835 that John Batman officially claimed the establishment of Melbourne. Five years after its official beginning, Melbourne's population had already reached 7,000. Water pumps were installed on the northern bank of the Yarra River. Mem with water carts sold water, door to door, for three shillings a barrel, equal to about 30 cents for 550 litres. Due to the Victorian gold rush of the 1850s, Melbourne's population rapidly increased and Melbourne was transformed into a major city. At the same time many new industries and buildings were being developed. These factors all meant that systems needed to be created to supply water to Melbourne. And in 1857, Yan Yean Reservoir, Melbourne's first water supply reservoir, was completed and began to supply water to Melbourne, which by now had a population of 100,000.