NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources

NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources Solutions to each chapter is provided in the list so that you can easily browse throughout different chapters NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources Notes and select need one. NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources Question Answers Download PDF. NIOS Study Material of Class 12 Environmental Science Paper Code 333.

NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources

Also, you can read the NIOS book online in these sections Solutions by Expert Teachers as per National Institute of Open Schooling (NIOS) Book guidelines. These solutions are part of NIOS All Subject Solutions. Here we have given NIOS Class 12 Environmental Science Chapter 29 Fresh Water Resources Solutions, NIOS Senior Secondary Course Environmental Science Solutions for All Chapter, You can practice these here.

Fresh Water Resources

Chapter: 29

Module 8 A: Water Resource Management

Textual Question Answer

INTEXT QUESTIONS 29.1

1. What fraction of total water available on earth is fresh water?

Ans: About 2.7%. 

2. Water covers about three quarters of the earth’s surface but how much of it is fresh water?

Ans: That’s the total water on Earth, not freshwater. Freshwater is only about 2.7% of total water, and usable fresh water is much less.

3. Name the three resources of fresh water.

Ans: Lakes, rivers, ground water.

INTEXT QUESTIONS 29.2 

1. Why does usable water require treatment?

Ans: Because water used for drinking, bathing, washing, cleaning etc. and to protect the health of the community. 

2. Name the steps in water treatment.

Ans: Step of water treatment:

(i) Clarification or sedimentation Coagulation and fluoridation Filtration.

(ii) Disinfection Chlorination Ozone.

3. What is fluorosis?

Ans: Fluorosis is a crippling and painful disease caused by intake of fluoride. 

4. How is water rid of iron at the community level?

Ans: By using a sequential process of aeration, reaction-cum-setting and filtration. 

5. What harm does arsenic cause if consumed with water contaminated with it?

Ans: It may cause a number of skin disorders or even cancer.

INTEXT QUESTIONS 29.3 

1. What is meant by ‘water quality’?

Ans: Those physical, chemical or biological characteristics of water by which the user evaluates the acceptability of water. 

2. State one example to express that concept of water quality differs with the purpose of using water.

Ans: It is based on the physical, chemical or biological quality of water, removal of toxic substances for sake of human health, we require water supply by pure wholesome and potable. 

3. Name any two major water quality issues of our country.

Ans: Water scarcity wholesome and potable. Pathogenic pollution, oxygen depletion etc. or any other. 

4. What is eutrophication?

Ans: Enrichment of nutrients like phosphates and nitrates. Promotes excess growth of algae in water bodies. 

5. Why do certain aquatic areas require special protection?

Ans: Because for protection of rare species and survival of aquatic environment. 

INTEXT QUESTIONS 29.4 

1. State an abstractive use and an instream of water.

Ans: Domestic water supply, irrigation.

2. Of what benefit are dams and canals drawn from rivers?

Ans: Ample water for irrigation, production of electricity. 

3. State two causes of long-term ecological damage to our river.

Ans: Diversions of river stream and long term environment damage, pollution.

TERMINAL EXERCISE

1. Describe the distribution of freshwater on earth. 

Ans: Freshwater has a little composition. A little fraction is of freshwater and is available for drinking. Freshwater is mostly frozen In the form of ice and glaciers. The three-quarter part of the earth is covered with water, 97,2% of water is occupied by the ocean, which is marine and not suitable for drinking. Freshwater is about 2.7% of total water.

2. Explain in brief the water resource distribution of India.

Ans: Water is distributed into resources like lakes, rivers, and in the form of underground water. The flow of rivers and the stratification of lakes are dependent on the climate conditions. Groundwater is recharged when surface water flows to underground land. Its recharging rate is very slow.

3. How water is purified for drinking? 

Ans: Water is purified by sedimentation and disinfection. Sedimentation removes the suspended particles, and disinfection is to remove the pathogens. Sedimentation occurs by coagulation, flocculation, or by filtration of the water. Coagulation settles down the large particles. Flocculation is the formation of flocs. Floc is the association of smaller particles to form one large insoluble particle. Filtration is done with the help of membrane or other porous filters like sand or gravel filters. Disinfection is done by the addition of bleaching powder called chlorination and by the addition of ozone.

4. Why water is required to be purified for drinking? 

Ans: Drinking water should be pure and potable. It should be free of any kind of contamination to prevent diseases and maintain health. The water is contaminated with dissolved minerals like trace metals and nitrate. Trace metals like arsenic, mercury, and cadmium are toxic to the body. Nitrate is poisonous and causes blue-baby disease when nitrate contaminated water Is used for drinking. Pathogen contaminated water results in water-borne diseases and pesticides contaminated cause biomagnification. Therefore drinking water should be pure.

5. Why ground water is safe for drinking? 

Ans: Groundwater is generally considered safer than surface water because it undergoes natural filtration through soil and rocks, which removes many pathogens and suspended particles. However, in some regions, it may still be contaminated with fluoride, arsenic, or nitrates.

6. How excess fluoride is removed from water? 

Ans: Activated aluminum is used to remove the excess fluoride from water in the water treatment plants.

7. How in stream uses affect water quality?

Ans: In-stream uses such as hydropower generation, navigation, fisheries, and recreation can affect water quality by altering flow, temperature, oxygen levels, and sometimes adding pollutants.

8. What are the main water quality issues in India? 

Ans: The main water quality Issues in India are contamination of water, the toxicity of water, sewage leaks and throwing of trash in fresh water bodies such as rivers.

9. How an agricultural activity affects water quality? 

Ans: The agricultural activities such as the use of pesticides, fungicides, insecticides, inorganic chemicals et cetera affect the water quality These get dissolved in water and make water toxic.

10. How water quality is altered due to dumping of wastes?

Ans: Dumping of domestic sewage, industrial effluents, plastics, and chemical waste into water bodies reduces oxygen levels, increases toxicity, adds pathogens, and alters the pH, making water unfit for drinking and aquatic life.