Water Resources Notes PDF

You already know that three-fourth of the WATER SCARCITY AND THE NEED FOR WATER earth’s surface is covered with water, but only CONSERVATION AND MANAGEMENT a small proportion of it accounts for freshwater that can be put to use. This Given the abundance and renewability of...

You already know that three-fourth of the WATER SCARCITY AND THE NEED FOR WATER earth’s surface is covered with water, but only CONSERVATION AND MANAGEMENT a small proportion of it accounts for freshwater that can be put to use. This Given the abundance and renewability of freshwater is mainly obtained from surface water, it is difficult to imagine that we may run off and ground water that is continually suffer from water scarcity. The moment we being renewed and recharged through the speak of water shortages, we immediately hydrological cycle. All water moves within the associate it with regions having low rainfall hydrological cycle ensuring that water is a or those that are drought prone. We renewable resource. instantaneously visualise the deserts of You might wonder that if three-fourth of Rajasthan and women balancing many the world is covered with water and water is ‘matkas’ (earthen pots) used for collecting a renewable resource, then how is it that and storing water and travelling long countries and regions around the globe suffer distances to get water. True, the availability from water scarcity? Why is it predicted that of water resources varies over space and time, by 2025, nearly two billion people will live in mainly due to the variations in seasonal and absolute water scarcity? annual precipitation, but water scarcity in Rationalised-2023-24 most cases is caused by over-exploitation, consequent greater demands for water, and excessive use and unequal access to water unequal access to it. A large population among different social groups. requires more water not only for domestic Where is then water scarcity likely to use but also to produce more food. Hence, to occur? As you have read in the hydrological facilitate higher food-grain production, water cycle, freshwater can be obtained directly resources are being over-exploited to expand from precipitation, sur face run off and irrigated areas for dry-season agriculture. groundwater. Irrigated agriculture is the largest consumer Is it possible that an area or region may of water. Now it is needed to revolutionise the have ample water resources but is still facing agriculture through developing drought water scarcity? Many of our cities are such resistant crops and dry farming techniques. examples. Thus, water scarcity may be an You may have seen in many television outcome of large and growing population and advertisements that most farmers have their Water, Water Everywhere, Not a Drop to Drink: After a heavy downpour, a boy collects drinking water in Kolkata. Life in the city and its adjacent districts was paralysed as incessant overnight rain, meaning a record 180 mm, flooded vast area and disruted traffic. A Kashmiri earthquake survivor carries water in the snow in a devastated village. Fig. 3.1: Water Scarcity 20 CONTEMPORARY INDIA – II Rationalised-2023-24 own wells and tube-wells in their farms for long-term basis by ensuring functionality of irrigation to increase their produce. But have the tap water connections. (Source: Economic you ever wondered what this could result in? Survey 2020–21, p.357) That it may lead to falling groundwater levels, India’s rivers, especially the smaller ones, adversely affecting water availability and food have all turned into toxic streams. And even security of the people. the big ones like the Ganga and Yamuna Post-independent India witnessed are far from being pure. The assault on intensive industrialisation and urbanisation, India’s rivers – from population growth, creating vast opportunities for us. Today, large agricultural modernisation, urbanisation and industrial houses are as commonplace as the industrialisation – is enormous and growing industrial units of many MNCs (Multinational by the day….. This entire life stands Corporations). The ever-increasing number of threatened. industries has made matters worse by exerting Source: The Citizens’ Fifth Report, CSE, 1999. pressure on existing freshwater resources. Industries, apart from being heavy users of You may have already realised that the need water, also require power to run them. Much of the hour is to conserve and manage our of this energy comes from hydroelectric power. water resources, to safeguard ourselves from Today, in India hydroeclectric power health hazards, to ensure food security, contributes approximately 22 per cent of the continuation of our livelihoods and productive total electricity produced. Moreover, activities and also to prevent degradation of our multiplying urban centres with large and natural ecosystems. Over exploitation and dense populations and urban lifestyles have mismanagement of water resources will not only added to water and energy impoverish this resource and cause ecological requirements but have further aggravated the crisis that may have profound impact on problem. If you look into the housing societies our lives. or colonies in the cities, you would find that most of these have their own groundwater pumping devices to meet their water needs. From your everyday experiences, write a short Not surprisingly, we find that fragile water proposal on how you can conserve water. resources are being over-exploited and have caused their depletion in several of these cities. M U L T I -P U R P O S E R I V E R PR O J E C T S AND So far we have focused on the quantitative INTEGRATED WATER RESOURCES MANAGEMENT aspects of water scarcity. Now, let us consider But, how do we conserve and manage water? another situation where water is sufficiently Archaeological and historical records show available to meet the needs of the people, but, that from ancient times we have been the area still suffers from water scarcity. This constructing sophisticated hydraulic scarcity may be due to bad quality of water. structures like dams built of stone rubble, Lately, there has been a growing concern that reservoirs or lakes, embankments and canals even if there is ample water to meet the needs for irrigation. Not surprisingly, we have of the people, much of it may be polluted by continued this tradition in modern India by domestic and industrial wastes, chemicals, building dams in most of our river basins. pesticides and fertilisers used in agriculture, thus, making it hazardous for human use. Hydraulic Structures in Ancient India Government of India has accorded highest priority to improve the quality of life and In the first century B.C., Sringaverapura enhance ease of living of people especially those near Allahabad had sophisticated water living in rual areas by announcing the Jal harvesting system channelling the flood Jeevan Mission (JJM). The Goal of JJM is to water of the river Ganga. enable every rural household get assured During the time of Chandragupta Maurya, supply of potable piped water at a service level dams, lakes and irrigation systems were of 55 litres per capita per day regularly on extensively built. WATER RESOURCES 21 Rationalised-2023-24  Evidences of sophisticated irrigation works have also been found in Kalinga, A dam is a barrier across flowing water that (Odisha), Nagarjunakonda (Andhra obstructs, directs or retards the flow, often Pradesh), Bennur (Karnataka), Kolhapur creating a reservoir, lake or impoundment. (Maharashtra), etc. “Dam” refers to the reservoir rather than the structure. Most dams have a section called a In the 11th Century, Bhopal Lake, one of the spillway or weir over which or through which largest artificial lakes of its time was built. it is intended that water will flow either In the 14th Century, the tank in Hauz Khas, intermittently or continuously. Dams are Delhi was constructed by Iltutmish for classified according to structure, intended supplying water to Siri Fort area. purpose or height. Based on structure and Source: Dying Wisdom, CSE, 1997. 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. handicap of its colonial past. 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 industrialisation and growth of the urban economy. Find out more about any one traditional Fig. 3.2: Hirakud Dam method of building dams and irrigation works. What are dams and how do they help us in conserving and managing water? Dams were traditionally built to impound rivers and We have sown the crops in Asar rainwater that could be used later to irrigate We will bring Bhadu in Bhadra agricultural fields. Today, dams are built not Floods have swollen the Damodar just for irrigation but for electricity generation, The sailing boats cannot sail water supply for domestic and industrial uses, flood control, recreation, inland Oh! Damodar, we fall at your feet navigation and fish breeding. Hence, dams are Reduce the floods a little now referred to as multi-purpose projects Bhadu will come a year later where the many uses of the impounded water Let the boats sail on your surface are integrated with one another. For example, (This popular Bhadu song in the Damodar in the Sutluj-Beas river basin, the Bhakra – valley region narrates the troubles faced by Nangal project water is being used both for people owing to the flooding of Damodar river hydel power production and irrigation. known as the river of sorrow.) Similarly, the Hirakud project in the Mahanadi basin integrates conservation of In recent years, multi-purpose projects water with flood control. and large dams have come under great Multi-purpose projects, launched after scrutiny and opposition for a variety of Independence with their integrated water reasons. Regulating and damming of rivers resources management approach, were thought affect their natural flow causing poor sediment of as the vehicle that would lead the nation to flow and excessive sedimentation at the bottom development and progress, overcoming the of the reservoir, resulting in rockier stream 22 CONTEMPORARY INDIA – II Rationalised-2023-24 beds and poorer habitats for the rivers’ aquatic Source: S. Sharma, quoted in In the Belly of life. Dams also fragment rivers making it the River. Tribal conflicts over development in Narmada valley, A. Baviskar, 1995. 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 Sardar Sarovar Dam has been built over decomposition over a period of time. the Narmada River in Gujarat. This is one Multi-purpose projects and large dams of the largest water resource projects of have also been the cause of many new India covering four states—Maharashtra, environmental movements like the ‘Narmada Madhya Pradesh, Gujarat and Rajasthan. Bachao Andolan’ and the ‘Tehri Dam Andolan’ The Sardar Sarovar project would meet the etc. Resistance to these projects has primarily requirement of water in drought-prone and been due to the large-scale displacement of desert areas of Gujarat (9,490 villages and local communities. Local people often had to 173 towns) and Rajasthan (124 villages). give up their land, livelihood and their meagre Source: http://www.sardarsarovardam.org/ access and control over resources for the project.aspx greater good of the nation. So, if the local people are not benefiting from such projects Irrigation has also changed the cropping then who is benefited? Perhaps, the pattern of many regions with farmers shifting landowners and large farmers, industrialists to water intensive and commercial crops. This and few urban centres. Take the case of the has great ecological consequences like landless in a village – does he really gain from salinisation of the soil. At the same time, it such a project? has transformed the social landscape i.e. increasing the social gap between the richer landowners and the landless poor. As we can Narmada Bachao Andolan or Save see, the dams did create conflicts between Narmada Movement is a Non Governmental people wanting different uses and benefits Organisation (NGO) that mobilised tribal from the same water resources. In Gujarat, people, farmers, environmentalists and the Sabarmati-basin farmers were agitated human rights activists against the Sardar and almost caused a riot over the higher Sarovar Dam being built across the priority given to water supply in urban areas, Narmada river in Gujarat. It originally particularly during droughts. Inter-state water focused on the environmental issues related disputes are also becoming common with to trees that would be submerged under the regard to sharing the costs and benefits of the dam water. Recently it has re-focused the multi-purpose project. aim to enable poor citizens, especially the oustees (displaced people) to get full rehabilitation facilities from the government. Do you know that the Krishna-Godavari People felt that their suffering would not dispute is due to the objections raised by be in vain… accepted the trauma of Karnataka and Andhra Pradesh displacement believing in the promise of governments? It is regarding the diversion irrigated fields and plentiful harvests. So, of more water at Koyna by the Maharashtra often the survivors of Rihand told us that they government for a multipurpose project. This accepted their sufferings as sacrifice for the would reduce downstream flow in their sake of their nation. But now, after thirty bitter states with adverse consequences for years of being adrift, their livelihood having agriculture and industry. even being more precarious, they keep asking: “Are we the only ones chosen to make sacrifices for the nation?” Make a list of inter-state water disputes. WATER RESOURCES 23 Rationalised-2023-24  India: Major Rivers and Dams 24 CONTEMPORARY INDIA – II Rationalised-2023-24  Most of the objections to the projects arose RAINWATER HARVESTING due to their failure to achieve the purposes Many thought that given the disadvantages for which they were built. Ironically, the dams and rising resistance against the multi- that were constructed to control floods have purpose projects, water harvesting system was triggered floods due to sedimentation in the a viable alternative, both socio-economically reservoir. Moreover, the big dams have mostly and environmentally. In ancient India, along been unsuccessful in controlling floods at the with the sophisticated hydraulic structures, time of excessive rainfall. You may have seen there existed an extraordinary tradition of or read how the release of water from dams water-harvesting system. People had in-depth during heavy rains aggravated the flood knowledge of rainfall regimes and soil types situation in Maharashtra and Gujarat in 2006. and developed wide ranging techniques to The floods have not only devastated life and harvest rainwater, groundwater, river water property but also caused extensive soil and flood water in keeping with the local erosion. Sedimentation also meant that the ecological conditions and their water needs. flood plains were deprived of silt, a natural In hill and mountainous regions, people built fertiliser, further adding on to the problem of diversion channels like the ‘guls’ or ‘kuls’ of land degradation. It was also observed that the Western Himalayas for agriculture. the multi-purpose projects induced ‘Rooftop rainwater harvesting’ was commonly earthquakes, caused water-borne diseases and practised to store drinking water, particularly pests and pollution resulting from excessive in Rajasthan. In the flood plains of Bengal, use of water. people developed inundation channels to Collect information about flood prone areas of the country WATER RESOURCES 25 Rationalised-2023-24 irrigate their fields. 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. Fig. 3.4 (a) Recharge through Hand Pump In the semi-arid and arid regions of Rajasthan, particularly in Bikaner, Phalodi a n d B a r m e r, a l m o s t a l l t h e h o u s e s traditionally had underground tanks or tankas for storing drinking water. The tanks could be as large as a big room; one household in Phalodi had a tank that was 6.1 metres deep, 4.27 metres long and 2.44 metres wide. The tankas were part of the well-developed rooftop rainwater harvesting system and 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 (b) Recharge through Abandoned Dugwell was usually not collected as this would Rooftop rainwater is collected using a PVC pipe clean the roofs and the pipes. The rainwater Filtered using sand and bricks from the subsequent showers was then Underground pipe takes water to sump for immediate usage collected. Excess water from the sump is taken to the well The rainwater can be stored in the Water from the well recharges the underground tankas till the next rainfall making it an Take water from the well (later) extremely reliable source of drinking water Fig 3.3: Rooftop Rainwater Harvesting when all other sources are dried up, 26 CONTEMPORARY INDIA – II Rationalised-2023-24  Fortunately, in many parts of rural and urban India, rooftop rainwater harvesting is being successfully adapted to store and conserve water. In Gendathur, a remote backward village in Mysuru, Karnataka, villagers have installed, in their household’s rooftop, rainwater harvesting system to meet their water needs. Nearly 200 households have installed this system and the village has earned the rare distinction of being rich in rainwater. See Fig. 3.6 for a better A kul leads to a circular village tank, as the above understanding of the rooftop rainwater in the Kaza village, from which water is released harvesting system which is adapted here. as and when required. Gendathur receives an annual precipitation of Fig 3.5: Traditional method of rainwater 1,000 mm, and with 80 per cent of collection harvesting efficiency and of about 10 fillings, every house can collect and use about 50,000 litres of water particularly in the summers. Rainwater, or annually. From the 200 houses, the net amount palar pani, as commonly referred to in of rainwater harvested annually amounts to these parts, is considered the purest form 1,00,000 litres. of natural water. Many houses constructed underground rooms adjoining the ‘tanka’ to beat the summer heat as it would keep the room cool. Rooftop rainwater harvesting is the most common practice in Shillong, Meghalaya. It is interesting because Cherapunjee and Mawsynram situated at a distance of 55 km. from Shillong receive the highest rainfall in the world, yet the state capital Shillong faces acute shortage of water. Nearly every household in the city has a Rooftop harvesting was common across the towns rooftop rainwater harvesting structure. and villages of the Thar. Rainwater that falls on the sloping roofs of houses is taken through a pipe into Nearly 15-25 per cent of the total water an underground tanka (circular holes in the ground). requirement of the household comes from built in the main house or in the courtyard. The rooftop water harvesting. picture above shows water being taken from a neighbour’s roof through a long pipe. Here the neighbour’s rooftop has been used for collection of rainwater. The picture shows a hole through which rainwater flows down into an underground tanka. Find out other rainwater harvesting systems existing in and around your locality. Fig. 3.6 Today, in western Rajasthan, sadly the Tamil Nadu is the first state in India practice of rooftop rainwater harvesting is on which has made rooftop rainwater the decline as plenty of water is available due harvesting structure compulsory to all to the perennial Indira Gandhi Canal, though the houses across the state. There are some houses still maintain the tankas since legal provisions to punish the defaulters. they do not like the taste of tap water. WATER RESOURCES 27 Rationalised-2023-24  BAMBOO DRIP IRRIGATION SYSTEM In Meghalaya, a 200-year-old system of tapping stream and spring water by using bamboo pipes, is prevalent. About 18-20 litres of water enters the bamboo pipe system, gets transported over hundreds of metres, and finally reduces to 20-80 drops per minute at the site of the plant. Picture 1: Bamboo pipes are used to divert perennial springs on the hilltops to the lower reaches by gravity. Picture 2 and 3: The channel sections, made of bamboo, divert Picture 4: If the pipes pass a road, water to the plant site where it is distributed into branches, again they are taken high above the land. made and laid out with different forms of bamboo pipes. The flow of water into the pipes is controlled by manipulating the pipe positions. Picture 5 and 6 Reduced channel sections and diversion units are used at the last stage of water application. The last channel section enables water to be dropped near the roots of the plant. Fig 3.7 1. Collect information on how industries are polluting our water resources. 2. Enact with your classmates a scene of water dispute in your locality. 28 CONTEMPORARY INDIA – II Rationalised-2023-24  EXERCISES EXERCISES EXERCISES EXERCISES EXERCISES 1. Multiple choice questions. (i) Based on the information given below classify each of the situations as ‘suffering from water scarcity’ or ‘not suffering from water scarcity’. (a) Region with high annual rainfall. (b) Region having high annual rainfall and large population. (c) Region having high annual rainfall but water is highly polluted. (d) Region having low rainfall and low population. (ii) Which one of the following statements is not an argument in favour of multi- purpose river projects? (a) Multi-purpose projects bring water to those areas which suffer from water scarcity. (b) Multi-purpose projects by regulating water flow helps to control floods. (c) Multi-purpose projects lead to large scale displacements and loss of livelihood. (d) Multi-purpose projects generate electricity for our industries and our homes. (iii) Here are some false statements. Identify the mistakes and rewrite them correctly. (a) Multiplying urban centres with large and dense populations and urban lifestyles have helped in proper utilisation of water resources. (b) Regulating and damming of rivers does not affect the river’s natural flow and its sediment flow. (c) In Gujarat, the Sabarmati basin farmers were not agitated when higher priority was given to water supply in urban areas, particularly during droughts. (d) Today in Rajasthan, the practice of rooftop rainwater water harvesting has gained popularity despite high water availability due to the Indira Gandhi Canal. 2. Answer the following questions in about 30 words. (i) Explain how water becomes a renewable resource. (ii) What is water scarcity and what are its main causes? (iii) Compare the advantages and disadvantages of multi-purpose river projects. 3. Answer the following questions in about 120 words. (i) Discuss how rainwater harvesting in semi-arid regions of Rajasthan is carried out. (ii) Describe how modern adaptations of traditional rainwater harvesting methods are being carried out to conserve and store water. WATER RESOURCES 29 Rationalised-2023-24