Water plays very important role in our life.Higlight about the importance of water. Write long ans....
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Answer:
Explanation:
Water is an essential nutrient and plays a key role in the human body. We can survive up to several weeks without food, but only a few days without water. Every system in the body, from cells and tissues, to vital organs requires water to function.
Did you know that:
Water carries nutrients to all cells in our body and oxygen to our brain
Water allows the body to absorb and assimilate minerals, vitamins, amino acids, glucose and other substances
Water flushes out toxins and waste
Water helps to regulate body temperature
Water acts as a lubricant for joints and muscles
Apart from drinking it to survive, people have many other uses for water. These include:
cooking
washing their bodies
washing clothes
washing cooking and eating utensils; such as billies, saucepans, crockery and cutlery
keeping houses and communities clean
recreation; such as swimming pools
keeping plants alive in gardens and parksSources of water
There are many ways in which we can collect water. The main sources are discussed below.
Surface water
This is water which falls to the ground as rain or hail.
This water is collected from a special area called a catchment. The catchment feeds water into a holding area via rivers, streams and creeks. The water is then stored in a natural or artificial (manmade) barrier called a dam or reservoir. Dams are usually placed at the lower end of a valley.
Catchment areas are usually far away from towns or cities to lessen the chance of the water being polluted. There are laws which control human activities, such as farming and recreation in catchment areas and on dams to make sure that water supplies are kept potable.
Fig. 6.3: A surface water dam.
Fig. 6.3: A surface water dam.
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Rivers or lakes
Town or community water supplies are sometimes drawn directly from nearby rivers or lakes.
Fig. 6.4: Rivers and lakes can supply water.
Fig. 6.4: Rivers and lakes can supply water.
Springs
These are found where underground water flows out of the ground naturally without the use of bores, wells or pumps.
Springs often occur towards the bottom of a hill or on sloping ground.
Fig. 6.5: A spring
Fig. 6.5: A spring.
Rock catchment areas and rockholes
Sometimes large rocky outcrops contain low areas in which water is trapped. These low areas make good natural dams. Often a wall can be built to increase the amount of trapped water.
Fig. 6.6: A rockhole
Fig. 6.6: A rockhole.
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Excavated dams
Excavated dams are made by scooping out soil to make a large shallow hole. These dams are sometimes placed at the bottom of a slope to aid water collection. However, this can only be done in areas where the soil will not allow the water to drain away very easily through the ground. For example, in clay soils.
Soils which do not allow water to drain away are called impervious.
If a community wants a dam in an area where the soil is not impervious this can still be done by digging the hole and lining it with clay or an impervious liner, such as concrete or heavy plastic. Excavated dams are often used by farmers to supply water to stock.
Fig. 6.7: An excavated dam.
Fig. 6.7: An excavated dam.
There is often a layer of water lying beneath the ground surface, trapped by an impervious layer of rock which will not allow it to drain away. The water may be close to ground level or it may be deep in the ground. This layer of water is called the water table.
When this water table is close to ground level the water may actually come to the surface and create a permanent wet area called a soak. This usually occurs in low lying areas or hollows.
Soaks are affected by changes in the depth of the water table. That is, if the water table drops then soaks may dry up. Some causes of this can be drought or overuse of ground water by people.
Fig. 6.8: A soak.