why do large areas in Australia not have any rivers ?
Answers
Rivers in central Australia are unusual in that they all rise in the arid zone and end in the arid zone In most of the world, desert rivers enter from humid areas. There is no permanent flowing water in any waterways except springs. Central Australia does not have a wet and a dry season. However, large storms tend to be more common in summer when the occasional remnants of tropical cyclones drift over central Australia. Australian rivers are up to 1000 times more variable in mean annual discharge than most European and North American rivers (Gale & Bainbridge 1990). The only occasion that stream flow occurs is after rainfall events. In small catchments streamflows are relatively short, perhaps a few hours to a few days. At any one site on a larger river, flow typically lasts for a few days to a few weeks; flows lasting greater than one month are rare. Streamflow tends to travel slowly along the length of the river; Cooper Creek for example has gradients as low as 1.9cm/km (1.3in/mi). Thus, it may take one or two months for the water in the upper reaches to get to the lower reaches. When in flood, rivers such as Cooper Creek may spread as wide as 50km. Most rivers contain very little permanent water. All the water exists in a series of waterholes, most of which disappear after a year or two with no flow. What little physiochemical data exists demonstrates that most waterbodies have very broad temperature and salinity ranges (Glover 1982). Doddridge (1992), working in the lower Cooper Creek recorded an annual temperature range of 13 to 34°C (56-93°F). Turbidity, caused by fine clay particles, is typically exceptionally high.