The Great Artesian Basin Where does your water come from?
When we don’t have pipes bringing water to our home ….. <ul><li>People all over inland Australia get underground water to water their stock, grow their gardens and use in their own houses. </li></ul><ul><li>In some years there is plenty of rainwater too. </li></ul>
Good planets are hard to find … <ul><li>The Great Artesian Basin was formed between 100 and 250 million years ago. Water has been dated by scientists as being more than 2 million years old </li></ul><ul><li>Wow that’s old! </li></ul><ul><li>Imagine drinking 2 million </li></ul><ul><li>year old water </li></ul>
When the sea was higher …. <ul><li>The water level of the oceans use to be much higher and in fact the ocean even spread all over the inland area of north eastern Australia. </li></ul>This is the same area that is called the Great Artesian Basin today.
When the oceans dropped, the area covered by the inland sea became layers of sandstone and rock. The water in The Great Artesian Basin is often salty. Why might this be?
Scientists believe that water from rain and rivers soak through the rock slowly and is gathered in an aquifer where it stays until it is taken out through a bore or natural spring.
<ul><li>This diagram shows how the water flows in and is taken out of the Great Artesian Basin </li></ul>
<ul><li>Water comes out naturally from the Great Artesian Basin through mound springs. There are a number of these in northern South Australia. Dalhousie Springs are famous hot springs. </li></ul>
<ul><li>Water is pumped out from The Great Artesian basin through bores. </li></ul>
Not all scientists agree about whether the Artesian Basin is a renewable resource. That means the water will be replaced naturally as we take it out. This is called recharging The arrows on this map show that some scientists believe that the rivers and water catchments on the edge of the Great Artesian Basin will flow into it.
<ul><li>Professor Endersbee is an Australian Scientist who does not believe the Great Artesian Basin is able to be recharged from the water catchments and rivers on the edge of it. </li></ul><ul><li>When the Great Artesian Basin was first penetrated by bores, the water gushed out at high pressures and high discharges, the fountains extending 100 feet and more into the air. Today bores have to be sunk much further into the ground to get water and it doesn’t always come out strongly with high pressure. </li></ul>
<ul><li>People have taken out millions and millions of litres of water and more water is being taken out than can seep back into the Artesian Basin. </li></ul>
<ul><li>Water is a very precious resource </li></ul>Millions of people around the world don’t have water coming from taps, and they don’t even have access to clean water from streams or bores
<ul><li>What do you think we need to do to care for our water in Australia? </li></ul><ul><li>What if we start with the Great Artesian Basin? </li></ul>
Bibliography <ul><li>Great Artesian Basin Fact Sheet – Department for Water Resources Government of SA </li></ul><ul><li>Academy of Technical Sciences and Engineering Focus No 108, July/August 1999 - Emeritus Professor Endersbee </li></ul>
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