CLASS 7 Chapter 16 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 1.

  1. a) The freshwater stored in the ground is much more than that present in the rivers and lakes of the world. True
  2. b) Water shortage is a problem faced only by people living in rural areas. False
  3. c) Water from rivers is the only source for irrigation in the fields. False
  4. d) Rain is the ultimate source of water. False

Question 2. Explain how groundwater is recharged.

Solution 2. Groundwater is recharged through the process of infiltration. In this process rainwater and water from other water bodies such as rivers and ponds seeps through the soil and all the empty spaces and cracks deep below the ground are filled with water. This is how groundwater is recharged.

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

Solution 3. If there are ten tube-wells in a lane of fifty houses then the groundwater will get used up for domestic purposes. This will deplete the groundwater level and water table would go down.

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

Solution 4. We can adopt drip irrigation method to water all the plants in the garden. In this method water wastage is very less because water reaches only to the roots of the plant drop by drop. In this way we can minimise the use of water.

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

Solution 5. Following are the factors responsible for the depletion of water table:

Increase in population- Increased population means increased demand for water for domestic and drinking purpose. This results in reduction of the water table.

Industrialisation: for manufacturing purposes Industries need a lot of water. This also results in reduction of the water table.

Agriculture: In agriculture water is required in huge amount for growing crops this 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) People obtain groundwater through tube wells and hand pumps.

(b) Three forms of water are ice, water and vapour.

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

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

Solution 7.

(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.