Ch 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)
(b) Water shortage is a problem faced only by people living in rural areas. (F)
(c) Water from rivers is the only source for irrigation in the fields. (F)
(d) Rain is the ultimate source of water. (T)
Question: 2 - Explain how groundwater is recharged?

Answer: The surface water seeps down the ground through the porous layers of the soil. This process is called infiltration and is responsible for recharging the groundwater.

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

Answer: Ten tube-wells in a lane of fifty houses can lead people to mindlessly exploit the groundwater. This can lead to depletion of the water table in the long run.

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

Answer: Drip irrigation can be used in the garden to minimize the use of water.

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

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

There is more demand of water due to increasing population. Increasing population means there is ever increasing demand of water for various human activities.

Deforestation has removed a large portion of forest cover. This has disturbed the natural process of recharging the groundwater.

While demand for water has increased, the supply has reduced. The mismatch between demand and supply is mainly responsible for depletion of water table.

Question: 6 - Fill in the blanks with the appropriate answers:
(a) People obtain groundwater through________ and ________.

Answer: Wells and tube-wells

(b) Three forms of water are ________, ________ and ________.

Answer: Ice, water and vapour

(c) The water bearing layer of the earth is ________.

Answer: Aquifer

(d) The process of water seepage into the ground is called ________.

Answer: Infiltration

Question: 7 - Which one of the following is not responsible for water shortage?
(i) Rapid growth of industries
(ii) Increasing population
(iii) Heavy rainfall
(iv) Mismanagement of water resources

Answer: (iii) Heavy rainfall

Question: 8 - Choose the correct option. The total water
(i) In the lakes and rivers of the world remains constant.
(ii) Under the ground remains constant.
(iii) In the seas and oceans of the world remains constant.
(iv) Of the world remains constant.

Answer: (iv) Of the world remains constant