1.Why Are Dams Built?
- Humans build dams over rivers which act as artificial water bodies.
- Dams have a massive reservoir where the river water can be stored and diverted in different areas apart from the river's route.
- Also, this water is used to produce hydroelectricity.
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2.What Is the Importance of Groundwater? Why Is It Essential When It Is Not Readily Available for Use.
- Groundwater is a significant source of fresh water after rivers and lakes.
- The underground water is pumped with the help of bore wells and used for domestic and agricultural purposes.
- The level of groundwater affects the level of water in lakes and wells. The lower the groundwater level, the lower the water level in wells and lakes.
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3.What Are the Causes of Water Pollution?
- Around 1500 substances in different forms are recorded as pollutants in freshwater.
- The water gets polluted due to the following factors:
- Waste and chemicals are released from industries and factories.
- Dumping of sewage and garbage in water bodies.
- Overuse of detergents and cleaning chemicals which washes off to the water bodies.
- Overuse of fertilisers and pesticides in agricultural fields, which, when reaching the water bodies, pollute them.
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4.How Does Water From Farms and Sewage Pipelines Make the River Water Unfit? Does It Affect the Plants and Animals in the Water Bodies?
- The water from farms and sewage pipelines is full of chemicals and pollutants.
- These chemicals degrade the water quality in the water bodies, making it unsuitable for use.
- Also, due to fertilisers washed off, enormous water plants grow on the surface of the water leading to overconsumption of oxygen available in the water.
- It affects the animals in the water body and sometimes leads to migration or death.
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5.What Is ‘Hard Water’ and ’Soft Water?
- When the water contains a higher amount of minerals like calcium and magnesium in it, it is called hard water.
- Due to the presence of minerals, it tastes different.
- Soaps and detergents do not dissolve well in hard water; hence less foam is formed while using hard water. Underground water in some places is hard water.
- Soft water, however, contains very few or no minerals. It is mostly tasteless. Example: rainwater.
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6.In Some Places, You Get Plenty of Water in Wells, but in Others, You Do Not Get Any. Explain Why.
- The level of water in wells depends on the level of underground water.
- In the areas with open grounds that are not covered with cemented coverings, the rainwater is absorbed well by the soil, leading to the recharging of the aquifer.
- On the other hand, the covering of bricks and cemented roads do not allow the water to seep down the soil, leading to a low groundwater level.
- Therefore, in some places, you get plenty of water in wells, but in others, you do not get any.
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7.What Are the Effects of Flood?
The effects of floods are as follows:
- Loss of life and livestock.
- Damage to the crops.
- Scarcity of potable water.
- The onset of infectious diseases like diarrhoea and typhoid.
- The onset of infectious diseases like diarrhoea and typhoid.