NCERT 7th Class (CBSE) Science: Water: A Precious Resource

Question: How farming can also benefit from good water management.

Answer: Farming, which typically requires huge quantities of water, can also benefit from good water management. Drip irrigation is an economical way of using water. This technique involves the use of tubes to deliver water straight to the base of a plant, where it is taken up by the roots.

Question: Explain the role of water in the life of plants.

Answer: Plants need water to absorb nutrients from the soil and make their food. Without water, plants would die, and greenery would be lost. This, in turn, would mean the end of all life on the earth, because without plants, there would be no food, oxygen or rainfall. There would also be many other problems.

Question: Can we keep on drawing water from underground, how it will affect the water table?

Answer: Water drawn from under the ground gets replenished by seepage of rainwater; the water table is not affected as long as we draw as much water as is replenished by natural processes, and however it may go down if the water is not sufficiently replenished.

Question: Describe the role of water in life of animals and plants.

Answer: Water is used for various activities such as agriculture, industries, cooking, cleaning utensils,bathing, washing clothes, and, most importantly, for drinking.

Water is a precious source because all our daily activities are carried out with the help of water only. Water is found everywhere but not everywhere it is drinkable/ usable. Though the seas have no lack of water but still we can’t drink or use it anywhere. Water helps in nourishment of animals and plants. We can’t live without water and because it is scarce, that’s why water is precious.

Plants need water to absorb nutrients from the soil and make their food. Without water, plants would die, and greenery would be lost. This, in turn, would mean the end of all life on the earth, because without plants, there would be no food, oxygen or rainfall. There would also be many other problems.

Question: Explain the factors responsible for depletion of water table.

Answer: The factors responsible for depletion of water table are:

1. Increasing population creates demand for construction of houses, shops, offices, roads and pavements. This decreases the open areas like parks, and playgrounds. This, in turn, decreases the seepage of rainwater into the ground. A cemented floor does not allow water to seep in easily, while in a grass lawn water seeps through in no time. Moreover a huge amount of water is required for construction work. Often groundwater is used for this purpose. So, on the one hand we are consuming more groundwater, and on the other we are allowing lesser water to seep into the ground. This results in depletion of water table. In fact, the water table in some parts of many cities has gone down to alarmingly low levels.
2. Water is used by all the industries. Almost everything that we use needs water somewhere in its production process. The number of industries is increasing continuously. Water used by most of the industries is drawn from the ground.
3. A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems such as canals are there only in a few places. Even these systems may suffer from lack of water due to erratic rainfall. Therefore, farmers have to use groundwater for irrigation. Population pressure on agriculture forces increasing use of groundwater day by day. This results in depletion of water table.