Unit 1
Unit 2
Environmental Markets
The Supply of Water
You might think that any discussion about the supply of water is quite simple; it rains and we have water, while during a drought we have less water. On one level this is true, but as the demand for water doesn’t fall during a drought (and in some cases it can increase) it is necessary to use policies to ensure that the supply of water is regulated.
In addition, it is also true that waiting for rain is not the only way that we can gain access to water. Rain will fill our water catchment areas, and the runoff from a significant rain episode can cause the catchment levels to increase for several days. As snow melts at the end of Winter, stream levels will rise, and once again we will see extra water flowing into our dams. But recent history has shown us that this is not enough; we need to find ways to ensure that our water supply will be consistent into the future.
One solution is to create a desalination plant. It may seem ironic that our planet’s surface is more than two thirds water, and yet the majority of that water is not fit for drinking. Before we can consume sea water, the salt that is in the water needs to be removed. According to the Encyclopaedia of Desalination and Water Resources, around 97.5% of all of the water on our planet is saline, while only 2.5% is fit for drinking without any processing. If you follow the news, you will be aware that the Victorian government has committed to the development of a desalination plant in Wonthaggi. Perth has been operating its own desalination plant since 2006, and both Sydney and Adelaide have announced that they will soon have operations of their own. Not surprisingly, the largest desalination plants in the world are located in the Middle East; over 75% of the world’s desalination occurs in that region. For example, the Jebel Ali Desalination Plant in the United Arab Emirates has output of around 300 million cubic metres of water per year. Throughout the world, around twelve billion litres of water are produced by this method every day.
There are, however, strong criticisms about the process of desalination. It can be quite expensive, and when sea water is “cleaned” in this way it can have a drastic impact on the environment. For this reason, it is important to consider other alternatives. In some parts of the world, it is popular to use recycled water. Generally water that is recycled is only used for purposes other than drinking, such as to irrigate crops on farms. There are some places in the world where the process of recycling is completed to such an advanced level that the water can be safely consumed. For example, if you have ever visited Singapore then it is likely that you have consumed recycled water.
These supply options will only ever be used to supplement the natural access to water that we already have. This means that it is important that the government develops and maintains strategies to guarantee the water supply. For example, encouraging people to have rainwater tanks installed in their homes, or managing the water that flows through our drains after a storm are important considerations.
Finally, we should all be aware that significant water reserves exist as groundwater. In one sense this water can be considered “extra” above the water that we can see in our storage areas. On the other hand, there is a significant problem associated with this. Groundwater sits in porous areas under the surface of the Earth. At a certain depth the ground becomes completely saturated; this is known as the water table. Over time, our continued access of the water table has placed pressure on our groundwater reserves. This means that there is less water in the water table than there was even just a few years ago. Continued use of this water in this way will create shortages, compound environmental problems, and make erosion even more likely. Many plants and animals will die.
As a result, it is clear to see that the management of global water supplies is of paramount concern.
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