CBSE Class 10 Social Science Water Resources Assignment

INTRODUCTION

Even though three-fourth of the earth’s surface is covered with water , only a small proportion of it accounts for fresh water. This fresh water is mainly obtained from surface runoff and ground water that is continually being renewed and recharged through hydrological cycle. The hydrological cycle ensure that water is a renewable resource.

8.1 WATER, A VERY IMPORTANT AND CRITICAL RESOURCE OF INDIA

(i) In India the total availability of water depends upon monsoon which is very uncertain.
(ii) Water is used for drinking, domestic and various industrial purposes.
(iii) Agriculture has been claiming a greater and greater share of water day by day.
(iv) Water has become necessary for disposal of ever-growing municipal sewage and dirt.

(a) Water: Some Facts and Figures :
(i) 96.5 percent of the total volume of world’s water is estimated to exist as oceans and only 2.5 percent as freshwater. Nearly 70% of this occurs as ice sheets and glaciers, a little less than 30% is stored as groundwater in the water aquifers.
(ii) India receives nearly 4% of the global precipitation and ranks 133 in the world in terms of water availability per person per annum.
(iii) The total renewable water resources of India are estimated at 1897 sq km per annum.

8.2 CAUSES OF WATER SCARCITY IN INDIA

(i) Water scarcity in most cases is caused by over – exploitation, excessive use and unequal access to water among different social groups.
(ii) An outcome of large and growing population and consequent greater demands for water, and unequal access to it.
(iii) To facilitate higher food-grain production, water resources are being over - exploited to expand irrigated areas and dry-season agriculture.
(iv) Excessive use of underground water may lead to falling groundwater levels, adversely affecting water availability and food security of the people.
(v) The ever increasing number of industries has made matters worse by exerting pressure on existing freshwater resources. Industries, apart from being heavy users of water, also require power to run them. Much of this energy comes from hydroelectric power. Today, in India hydroelectric power contributes approximately 22 percent of the total electricity produced.
(vi) Multiplying urban centres with large and dense populations and urban life styles have not only added to water and energy requirements but have further aggravated the problem.
(vii) Water is sufficiently available to meet the needs of the people, but, the area still suffers from water scarcity. This scarcity may be due to bad quality of water.
(viii) Even if there is ample water to meet the needs of the people, much of it may be polluted by domestic and industrial wastes, chemicals , pesticides and fertilisers used in agriculture, thus, making it hazardous for human use.

8.3 MULTI-PURPOSE RIVER PROJECT

Archaeological and historical records show that from ancient times we have been constructing sophisticated hydraulic structures (Sringaverapur near Allahabad, dams, lakes and irrigation systems during the time of Chgandragupta Maurya, Bhopal Lake and the tank in Hauz Khas, Delhi) like dams built of stone rubble, reservoirs or lakes, enbankments and canals for irrigation.
A dam is a barrier across flowing water that obstructs, directs or retards the flow, often creating a reservoir, lake or impoundment. “Dam” refers to the reservoir rather than the structure. Dams are classified according to structure, intended purpose or height. Based on structure and the materials used, dams are classified as timber dams, embankment dams or masonry dams, with several subtypes. According to the height, dams can be categorised as large dams and major dams or alternatively as low dams, medium height dams and high dams.
A dam or a series of dam are built on a river and its tributaries to solve various purposes. Purposes solved through a Multi-Purpose River Project are :
(i) Control on flood and drought.
(ii) Checks soil erosion.
(iii) Provides water for irrigation, drinking and industrial purposes.
(iv) Generates electricity.
(v) Provides inland navigation.
(vi) Provides facilities for recreation.
(vii) Preservation of wildlife, forests and development of fisheries. Jawaharlal Nehru proudly proclaimed the dams as the ‘temples of modern India’; the reason being that it would integrate development of agriculture and the village economy with rapid indutrialisation and growth of the urban economy.

(a) Negative features of Multi-purpose River Valley project :
(i) Regulating and damming of rivers affect their natural flow causing poor sediment flow and excessive sedimentation at the bottom of the reservoir, resulting in rockier stream beds and poorer habitats for the rivers’ aquatic life.
(ii) Dams also fragment rivers making it difficult for aquatic fauna to migrate, especially for spawning. The reservoirs that are created on the floodplains also submerge the existing vegetation and soil leading to its decomposition over a period of time.
(iii) Resistance to these projects has primarily been due to the large-scale displacement of local communities .
(iv) These projects has also changed the cropping pattern of many regions with farmers shifting to water intensive and commercial crops.
(v) This has great ecological consequences like salinisation of the soil .
(vi) These projects has transformed the social landscape i.e. increasing the social gap between the richer landowners and the landless poor, create conflicts between people wanting different uses and benefits from the same water resources.
(vii) Inter-state water disputes are also becoming common with regard to sharing the costs and benefits of the multi-purpose project.
(viii) Most of the objections to the projects arose due to their failure to achieve the purposes for which they were built. Ironically, the dams that were constructed to control floods have triggered floods due to sedimentation in the reservoir, mostly been unsuccessful in controlling floods at the time of excessive rainfall.
(ix) Sedimentation also meant that the flood plains were deprived of silt, a natural fertiliser, further adding on the problem of land degradation.
(x) The multi-purpose projects induced earthquakes, caused water borne diseases and pests and pollution resulting from excessive use of water.

8.4 RAIN WATER HARVESTING

Technique of increasing the recharge of ground water by capturing and storing rain water. It’s objectives are:
(i) To meet the increasing demand of water.
(ii) Reduce runoff, avoiding flooding of roads.
(iii) Improve the quality and quantity of underground water level.

(a) Examples of rain water harvesting in India :
In ancient India, along with the sophisticated hydraulic structures, there existed an extraordinary tradition of water-harvesting system. People had in-depth knowledge of rainfall regimes and soil types and developed wide ranging techniques to harvest rainwater, groundwater, river water and flood water in keeping with the local ecological conditions and their water needs.
(i) In hill and mountainous regions, people built diversion channels like the ‘guls’ & ‘kuls’ of the Western Himalayas for agriculture.
(ii) Roof top rainwater harvesting was commonly practised to store drinking water particularly in Rajasthan.
(iii) In the flood plains of Bengal, people developed inundation channels to irrigate their fields.
(iv) In arid and semi arid regions, agricultural fields were converted into rain fed storage structures that allowed the water to stand and moisten the soil like the ‘khadins’ in Jaisalmer and ‘Johads’ in other parts of Rajasthan.

(b) Rainwater Harvesting in semi-arid regions of Rajasthan
In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi and Barmer, almost all the houses traditionally had underground tanks or tankas for storing drinking water. Tankas were built inside the main house or the courtyard. They were connected to the sloping roofs of the houses through a pipe. Rain falling on the rooftops would travel down the pipe and was stored in these underground ‘tankas’. The first spell of rain was usually not collected as this would clean the roofs and the pipes. The rainwater from the subsequent showers was then collected. Water stored in the tankas prove to be an extremely reliable source of drinking water when all other sources are dried up, is considered the purest form of natural water, many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool. In Gendathur, a remote backward village in Mysore, Karnataka, villagers have installed, in their household’s rooftop, rainwater harvesting system to meet their water needs.
Tamil Nadu is the first and the only state in India which has made roof top rainwater harvesting structure compulsory to all the houses across the state. There are legal provisions to punish the defaulters.

MCQ Questions for Class 10 Social Science Water Resources

Question : The total volume of the world’s water is estimated to exist as ocean:
(a) 75.5%    
(b) 85.5%   
(c) 95.5%   
(d) 65.5%
Answer : C 

Question : Roof top rainwater harvesting is the most common practice in-
(a) Shillong   
(b) Guwahati   
(c) Imphal   
(d) Patna
Answer : A 

Question : On which river has Nagarjun Sager Dam been constructed?
(a) River Coyana 
(b) River Krishna   
(c) River Godavari   
(d) river Tapti
Answer : B 

Question : How much %of the Earth’s Surface is covered with water?
(a) About 70%   
(b) About 90%   
(c) About 60%   
(d) None of these
Answer : A 

Question : What is the rank of India in the world countries in the terms of Water availability per person p.a.?
(a) 129th   
(b) 130th   
(c) 131st   
(d) 133rd
Answer : D 

Question : It is predicated that nearly 2 billion people will live in absolute water scarcity in the year of –
(a) 2015   
(b) 2020   
(c) 2025   
(d) 2030
Answer : C

Question : The first & the only state in India which has made Roof Top Rain water Harvesting Structured compulsory to all the across the state is –
(a) Karnataka   
(b) Tamil Nadu   
(c) Kerala   
(d) none of these
Answer : B  

Question : How is freshwater obtained?
Answer. Mainly obtained from surface run off and groundwater.

Question : What was the method use in the ancient period to conserve water?
Answer. Dam builds of stone rubble, reservoir or lake, embankment and canal for irrigation.

Question : What are the benefits of damn?
Answer. Irrigation, electricity generation, water supply for domestic and industrial uses, flood control, recreation, inland navigation and fish breeding.

Question : Why wear multipurpose project launched after independence of India?
Answer. Multipurpose project where thought of as a vehicle that would lead the nation to development and progress overcoming the handicap of its colonial past

Question : What wear “kuls” or “guls”?
Answer. These are the divergent channel for irrigation purpose. These are mainly used in western Himalaya for water harvesting and agriculture.

Question : What wear Johads and khadins?
Answer. In arid and semiarid region the agriculture field where converted into rain fed storage structure that allowed the water to stand and moisture the soil these were called khadins in jaisalmer and johad in other part of Rajasthan.

Question : State any three objectives of Rainwater harvesting?
Answer :    (a) To reduce run off water
(b) To raise the water table
(c) To reduce ground water pollution 

Question : What is multipurpose river valley project? State any two purposes which are fulfilled by a river valley project?
Answer :  Multipurpose river valley project consists a dam or series of dames on a river or rivers for fulfill many purposes like:
(a) irrigation   (b) electricity   (c) control flood   (d) check soil erosion   (e) inland navigation   (f) fisheries etc. 

Question : Mention three major sources of irrigation in India, which source of irrigation is more popular in southern state? and Why?
Answer : 
(I) The three major sources pf irrigation in India are –
(a) Canals   (b) Wells & tube wells   (c) Tanks
(II) Tank irrigation
(III) Because Southern States are mostly come under Deccan plateau which are not suitable for irrigation by canals 

Question : What is “Water scarcity” what are its main causes?
Answer : "Water scarcity” means shortage of water.
CAUSES: (may write any two)
(a) Unequal distribution of rainfall
(b) Large & growing population
(c) Over exploitation of water
(d)Wastage of water by people (Explain all in brief) 

Question : Name any two multipurpose river valley projects or dams which are causes of new social movements. Why did people oppose them?
Answer : Two Multipurpose project which are caused social movements –
(a) Narmada –Bachao Andolan
(b) Tehri-Dam Andolan
(c) Sardar Sarover Dam
-Large scale displacement of local communities
-Environment issues
-Demand for Rehabilitation facilities from Govt. 

Question : Explain in brief –
(a) Bamboo drip Irrigation System
(b)Khadins & Johads
(c) Guls & Kuls
Answer : (1) In Meghalaya, 200 years old system of tapping stream and spring water by using Bamboo –pipes.
(2) People built division channels from rivers for irrigation to their field in western Himalaya is called Guls or kuls .
(3) People developed inundation channels to irrigate their fields were converted into rain storage structure in particularly western Rajasthan Jaisalmer called Khadins and Johads in other parts of its state. 

Question : Why do we conserve water resources?
Answer :  i)To safeguard ours from health hazards
ii) To ensure food scarcity
iii) To protect natural ecosystem (Explain all in brief)