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Chapter Review:

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• Water is essential for all living beings. There can be no life without it.
• The world water day celebrating every year 22 March.
• About 71% of the earth’s surface is covered with water.
• Water exists in three forms: solid, liquid and vapour.
• The groundwater is stored between layers of hard rock below the water table. This is known as an aquifer.
• The rainwater can be used to recharge the groundwater. This is
  referred to as water harvesting or rainwater harvesting.
• A level where all the space between particles of soil and gaps between rocks are filled with water.The upper limit of this layer is called the water table.
• The solid form, snow and ice, is present as ice caps at the poles of the earth.
• Liquid water is present in oceans, lakes, rivers, and even underground.
• The gaseous form is the water vapour present in the air around us.

Exercise 

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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)

Answer:

(a) T  (b) F  (c) F  (d) T

2. Explain how groundwater is recharged?

Answer:

The rain water and water from other sources such as river 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 groundwater thus gets recharged by this process.

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

Answer:

The water table will be depleted. Atime will come when table fall below the pipe of tubewells. Water will not be fetched by these any more. 

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

Answer:

(i) By collecting rain water.

(ii)By using water after bath or washing utensils for watering in the garden.  

5. Explain the factors responsible for the depletion of water lable.

Answer:

(i) Increasing population: Increasing population creates demand for construction of houses, shops, offices, roads and pavements. This decrease the open areas likeparks, and playground.

(ii) Increasing industries: Water is used by all the industries. The number of industries is increasing continously. Water used by most of the industries is drawn from the ground

(iii) Agriculture activities: These irrigation system may suffer from lack of water due to erractic rainfall. Therefore, farmers have to use groundwater for irrigation.  

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 ________.

Answer:

(a) well and hand pumps (b) solid, liquid and gas (c) acquifer (d) infirltration.

7. Which one of the following is not responsbile for water shortage? 

(i) Rapid growth of industries

(ii) Increasing population

(iii) Heavy rainfall

(iv) Mismanagement of water resources 

Answer:

(iii) Heavy rainfall.

8. Choose the correct opton.

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.

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

Answer-

Groundwater and Water lable

Additional Question With Solutions: 

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Ques1– What is ground water?

Answer– There is the space between particles of soil and gaps between rocks are filled with water. This water is found under the ground table. The water found below the water table is called groundwater.

Ques2– What is called the process of seeping of water into the ground?

Answer– This is called infiltration.

Ques3– What is aquifer?

Answer– At places the groundwater is stored between layers of hard rock below the water table. This is known as an aquifer.

Ques4– Name the two process by which water of aquifers is pumped out.

Answer– (i)    wells       (ii) Hand pumps

Ques5– How can be refilled the ground water? Exaplain.

Answer– The ground water can be refilled by the following methods.

(i) By the rain water.

(ii) By the water harvesting, by the boaring.

Ques6– Which factors influence (affect) the ground water?

Answer– The factors which influence (affect) the ground water.

(i) Increase in population, industrial and agricultural activities

(ii) Scanty rainfall

(iii) Deforestation and decrease in the effective area for seepage of water.

Ques7 – Name those activities those results in depletion of water table.

Answer–

(i) Irrigation

(ii) Industrial use and constructions.

(iii) Drinking water.

Ques8 – What do you understand by water harvesting?

Answer- The rainwater can be used to recharge the groundwater. This is referred to as water harvesting or rain water harvesting.

Ques9 – Name three traditional methods for water harvesting.

Answer– Bawari, Well and Pond.

Ques10 – What is drip irrigation? What is its benefits?

Answer- Drip irrigation is a technique of watering plants by making use of narrow tubings which deliver water directly at the base of the plant. By this technique of irrigation uses less water.

Ques11 – Make a sketch showing groundwater and water table. Label it.

Answer-

Groundwater and Water lable

Additional Question with solution:

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Que: Suggest one traditional way of storing water from ancient time.

Ans: In ancient times, people used to make Bawris to store water.

Que: The earth tooks blue from space. Explain why?

Ans: The major surface area (71%) of the earth is covered with water. This imparts blue colour to the earth.

Que: Reservoir of dam helps us to manage water. How?

Ans:  The reservoir of dam or river can release water at our will. We can divert the flow of water at desired places where it is really needed and we can manage water resource effectively.

Que: The excessive use of water leads to a severe problem. write the problem.

Ans: The excessive use of water leads to water scarcity in an area.

Que: How much of the earth's surface is covered with water?

Ans: About two - third of tyhe earth's surface is covered with water?

Que: Mention the year which is celebrated as international year of freshwater?

Ans: The year 2003 was celebrated as International year of freshwater.

Que: State the consequences, if plants do not get enough water.

Ans: The plants will wilt and ultimately dry up in lack of water.

Que: Mention the source of groundwater.

Ans: Rainwater and water from the other sources like rivers, ponds, etc are the source of froundwater.

Que: From where do the worker get water for construction?

Ans: Worker get water from the underground water.

Que: Can we keep on drawing water from under the ground? How will it affect the water table?

Ans: No, we cannot keep on drawing water.

It causes the depletion of water table.

Que: As our population increases, we need more water for drinking, washing and other purposes. Does this affect the water table? Explain?

Ans: Yes, rising population leads to an increase inconsumption and at the same time, a decrease in the seepage of water into the. ground leads to the depletion of watertable.