Charleville, Outback Queensland is in the Murweh Shire which covers 43,905 km2 and also includes the towns of Augathella, Cooladdi and Morven. The Murweh Shire lies in a semi-arid zone, with climates ranging on average from 15 degrees celsius up to 37 degrees celsius during the summer months, and in the winter month's, temperatures range from 3 to 25 degrees. Charleville and the Shire are situated on the Great Artesian Basin. The Great Artesian Basin lies under approximately one-fifth of Australia over an area of 1,711,000 square kilometres. It extends beneath arid and semi-arid regions of Queensland, New South Wales, South Australia and the Northern Territory. The Great Artesian Basin was formed between 100 and 250 million years ago, beginning with sediments laid down in three large depressions, the Carpentaria Basin, the Eromanga Basin and the Surat Basin. During the deposition process alternating layers of sand and gravel, and clays and clayey sands, were laid down in floodplains and lakes. Sandy sediments consolidated to form permeable sandstone layers, and the clayey sediments became impermeable layers of mudstone and siltsones preventing water escaping from the permeable sandstone. After sedimentation ceased, uplift and erosion at the edges of the Basin exposed the uplifted permeable sandstone and rainwater was able to enter the sandstone and slowly percolate through the sandstone to fill the aquifer. Water moves through the sandstone at a rate of between one and five metres a year. Thickness of this sequence varies from less than 100 metres on the Basin extremities to over 3,000 metres in the deeper parts of the Basin. Water continues to infiltrate into the outcropping sandstone aquifers mainly along the eastern margins of the Basin, especially along the western slopes of the Great Dividing Range, and is constrained in the aquifers by the impermeable layers as it flows generally westward to the south-west over most of the Basin but to the north-west and north in the northern section. Natural discharge from the Basin occurs in mound springs where groundwater flows at the surface; these natural water sources are a valuable resource for wildlife. Travel West is based in the outback Queensland town of Charleville however their tours operate from Brisbane and Charleville and special group departures can be arranged from anywhere in Australia.