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Water is arguably the most important physical resource as it is the one that is...
Water is arguably the most important physical resource as it is the one that is essential to human survival. Understanding the global water cycle and how we use water is essential to planning a sustainable source of water for the future. In the UK there are areas where water supplies are limited, showin by recent droughts. Globally, there are many reas that do ot have enough water to support the current population adequately. Decisions will have to be made on the best way to use water in a world where there is climate change.
By the end of this unit you should be able to:
- using information from wells, the topography of the ground and a water table contour map, carry out the following: interpret cross-sections, calculate the thickness of the unsaturated zone, and the rate of groundwater flow; deduce the direction in which groundwater is flowing; and estimate the depth to the saline interface in a coastal area from the height of the water table;
- list the types of rock that usually make good aquifers, and assess how good an aquifer a rock could be, given its porosity and hydraulic conductivity;
- distinguish between unconfined and confined aquifers, and recognize conditions in confined aquifers that will produce a flowing artesian well;
- using suitable data, calculate the exploitable storage, specific yield and specific retention of an aquifer.
Many people have the impression that underground water occupies vast caverns, such as those in the Derbyshire Peak District, flowing from one cavern to another along underground rivers. This is a common misconception: underground caverns are fairly rare, but huge quantities of water exist underground, within rocks. This is because many rocks contain pores, spaces that come in all shapes and sizes. In sediments, and consequently sedimentary rocks, there are often pores between grains which can be filled with water. There may also be spaces between rock beds or along joints, fractures or fissures which can also contain water. However, before we look at pores in more detail we will examine how water gets into the rock.
This unit is from our archive and is an adapted extract from Earth's physical resources: origin, use and environmental impact (S278) which is no longer taught by The Open University. If you want to study formally with us, you may wish to explore other courses we offer in.
This is an extract from an Open University course which is no longer available to new students. If you found this interesting you could explore more free Environmental Science course units or view the range of currently available OU Environmental Science courses.