After other possibilities inspected around South Australia coast in 1836, Adelaide plains impress William Light for city
An 1845 view of the Adelaide plains from Glen Osmond through to St Vincent Gulf by Edward Frome, a successor as South Australia surveyor general to William Light who was immediately impressed by the plains as the place for a capital city.
Image courtesy Art Gallery of South Australia
Arriving at the South Australia province in August 1836, surveyor general William Light took the brig Rapid along its coast, explored possibilities for a capital city site, including Port Lincoln. He did this as appointed leader of the South Australian colonisation commissioners' "first expedition".
Light went north along the eastern coast of St Vincent Gulf where he was immediately impressed by the Adelaide plains and its rainfall.
Light found Holdfast Bay to be only a landing site and hardly qualifying as a “commodious harbor, safe and accessible at all seasons of the year” that the colonisation commissioners had requested. But, beyond the bay, Light saw that the land on the plain was fertile and wooded, and there appeared to be “an abundant supply of fresh water” all the year round. The plains were the backed by the foothills of the Mount Lofty Ranges that could trap rainfall. The Port Adelaide River would later be opened as the more suitable harbour.
Light carried out a site survey of the Adelaide plains to report to the commissioners and identify the amount and quality of land available, the water resources and drainage patterns, main topographical features and any likely barriers to development. He took observations from Green Hill, sketched the course of the River Torrens, the edge of the hills face, and generally fixed the position of the Para Plateau in relation to the coast between Holdfast Bay and the Port Adelaide River.
Light's rough sketch (in the information and art meaning of "sketch") was part of a rapidly prepared report to the colonisation ommissioners. It also foreshadowed Light's plan by outlining his preliminary concepts for positioning and design of the city. It fulfilled its intended purpose to provide information to his employers: the commissioners in England.
A sea level benchmark was established by Light at Holdfast Bay. From this, he was able to determine the approximate heights above sea level of the hills and the Para Plateau. It was likely that he used a theodolite to measure vertical angles for this, as well as slope angles from the plateau to the Port River to determine whether the grade would enable a canal to be feasibly connected to the River Torrens.
The River Torrens would be crucial in deciding the particular place on the plains for the city. It would also affect the splitting of the city into two sections on either side of the river and the shaping of that design.
The South Australian colonisation commissioners had also left it to Light select the design for the city and to select and layout the rural land parcels. Thus the layout of Adelaide's city and country land parcels could be directly attributed to William Light and his survey team.