 As a result, police patrols became more frequent.Between 1918 and 1921 large adjoining areas of South Australia, Western Australia and the Northern Territory were declared as Aboriginal reserves, as sanctuaries for a nomadic people who had virtually no contact with white people.In 1920, part of Uluru-Kata Tjuta National Park was declared an Aboriginal Reserve (commonly known as the South-Western or Petermann Reserve) by the Australian Government under the "Aboriginals Ordinance 1918".