# Class 7 Science NCERT Solutions for Chapter – 16 Water A Precious Resource

## Water A Precious Resource

Question 1.
Mark ‘T’ if the statement is True and ‘F’ if it is False:
(a)
The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. (T/F)
(b) Water shortage is a problem faced only by people living in rural areas. (T/F)
(c) Water from rivers is the only source for irrigation in the fields. (T/F)
(d) Rain is the ultimate source of water. (T/F)

Solution:
(a) T
(b) F
(c) F
(d) T.

Question 2.
Explain how groundwater is recharged?

Solution:
The rainwater and water from other sources such as rivers and ponds seeps through the soil and fills the empty spaces and cracks deep below the ground. The process of seeping of water into the ground is called infiltration. The ground water thus gets recharged by this process.

Question 3.
There are ten tubewells in a lane of fifty houses. What could he the long-term impact on the water table?

Solution:
The water table will deplete. Time will come when water table fall below the pipe of tubewells. No water will be fetched by these any more.

Question 4.
You have been asked to maintain a garden. How will you minimise the use of water?

Solution:

1.  By collecting rain water.
2.  By using water after washing clothes or utensils for watering in the garden.

Question 5.
Explain the factors responsible for the depletion of water table.

Solution:
There are three main causes of depletion of water table.

(i) Increasing population :
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.

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 whereas on the other hand, we are allowing lesser water to seep into the ground. This results in depletion of water table.

(ii) Increasing industries :
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.

(iii) Agricultural activities :
A majority of farmers in India depend upon rains for irrigating their crops. Irrigation systems jUcîi Cl’îs equals 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. The increased use of groundwater day by day results in depletion of water table.

Question 6.
Fill in the blanks with the appropriate answers :
(a)
People obtain groundwater through ………. and ………. .
(b) Three forms of water are ………. , ………. ,and ………. .
(c) The water bearing layer of the earth is ………. .
(d) The process of water seepage into the ground is called ………. .

Solution:
(a) wells; hand pumps
(b) solid (ice), liquid (water); gas (water vapour)
(c) aquifer
(d) infiltration.

Question 7.
Which one of the following is not responsible for water t shortage?

1.  Rapid growth of industries
2. Increasing population
3. Heavy rainfall
4. Mismanagement of water resources.

Solution:
3. Heavy rainfall.

Question 8.
Choose the correct option. The total water

1. in the lakes and rivers of the world remains constant.
2. under the ground remains constant
3. in the seas and oceans of the world remains constant.
4. of the world remains constant.

Solution:
4. of the world remains constant.

Question 9.
Make a sketch showing groundwater and water table. Label it

Solution: