7 Climatic Change - Implications for India’s Water Resources M LAL 7.1 BACKGROUND Water is vital to all forms of life on earth, from the simplest of living organisms to the most complex of human systems Lack of freshwater to drink, for use in industry and agriculture and for multitude of other purposes where water is essential, is a limiting factor - perhaps the most important factor - hindering development in many parts of the globe In South Asia, increasing water shortage and declining water quality from pollution during the past few decades has drawn attention to the inherent fragility and scarcity of water and led to concern about water availability to meet the requirements of the 21st century Because of increasing population and changing patterns of water use in South Asia, additional demand is likely to be accompanied by a sharp decline in per capita water availability While consumption of 1,000 m3 of water per year and per capita is considered a standard for “well-being” in the developed world, projection of annual water availability per capita by the year 2025 for South Asia is a mere 730 m3 This trend is declining in all parts of the world, including those that are considered to have ample water resources With the growing recognition of such issues as the possibility of global climate change, an increasing emphasis on the assessment of future availability of water on various spatial and temporal scales is needed A warmer climate will enhance the hydrological cycle, which implies higher rates of evaporation, and a greater proportion of liquid precipitation compared to solid precipitation; these physical mechanisms, associated with potential changes in precipitation amount and seasonality, will affect soil moisture, ground water reserves and the frequency of flood or drought episodes The supply of water is limited and governed by the renewal processes associated with the global hydrological cycle Future projections of changes in monsoon rainfall patterns are tenuous in currently available global climate models Moreover, it has been recognized now that the superimposed modes of climatic variability (e.g., El Niño and Southern Oscillation), which can disturb mean rainfall patterns on timescales ranging from seasons to decades, are important mechanisms to take into account but are not well predicted by the global climate models Water resources will come under increasing pressure in South Asia due to the changing climate Changes in climatic conditions will affect demand, supply and water quality In regions that are currently sensitive to water stress (arid and semi-arid regions of Copyright © 2005 Taylor & Francis Group plc, London, UK 156 IMPLICATIONS FOR INDIA’S WATER RESOURCES India), any shortfall in water supply will enhance competition for water use for a wide range of economic, social and environmental applications In the future, larger population will lead to heightened demand for irrigation and perhaps industrialization at the expense of drinking water Disputes over water resources may well be a significant social consequence in an environment degraded by pollution and stressed by climate change 7.2 INDIA’S GEOGRAPHY, POPULATION AND WATER NEEDS India is a land with diverse geographical and climatic endowments This large expanse of land (with 328 mha gross area) is bounded by the Himalayan range in the North and the sea on three sides encompasses varied geographical and climatic zones ranging from the hot desert of Thar in the Northwestern corner to the cold desert of Ladakh in the extreme North, the arid region of the Rann of Kutch in the West to the world’s wettest place, Cherrapunji, in the Northeast (Fig 7.1) With the icy continent of Antarctica as its major neighbor to the South with vast stretch of the Indian Ocean in between, India has the world’s tallest wall (the Himalayas) on its Northern boundary Adjoining the Himalayas further North is the Tibetan plateau that is large, massive and about km high - a gigantic slab of rock protruding up to the middle of the troposphere and acting as a large sized heat source at the mid-tropospheric level Physiographically, India comprises of seven regions, viz., (1) Northern Mountains (the Himalayas), (2) Indo-Gangetic Plains, (3) Central Highlands, (4) Peninsular Plateau, (5) East Coast, (6) West Coast, and (7) the Islands (Andaman & Nicobar group in the Bay of Bengal and Lakshadweep group in the Arabian Sea) India also has the world’s largest estuary and mangroves, the Sundarbans in the East and biologically rich mountain ranges of the Western Ghats along its West Coast Apart from this, India is a home to a billion people that is projected to increase to 1.7 billion by 2050 according to the high scenario assuming a fertility rate of 2.1% The surface water and ground water resources in India play vital roles in agriculture, fisheries, livestock production, forestry, and industrial activity Water and agriculture sectors in India are likely to be most sensitive to monsoon rainfall There have been considerable spatial and temporal variations in rainwater availability in recent years as a result of observed swing in the onset, continuity and withdrawal patterns of monsoon The pace of the green revolution seems to have started slowing down due to immense pressure on India’s land and water resources and indiscriminate addition of restorer inputs such as inorganic fertilizers, pesticides etc and their inefficient use Agriculture’s share in Gross Domestic Product (GDP) of India has also declined recently, thus marking a structural shift in the composition of the GDP Though traditionally, agriculture accounted for two-fifths of the GDP; it accounted for only 31% in 1990-1991 and 25% in 2001 (ADB, 2003) India’s GDP has shown robust growth (never less than 5% since 1990-1991) which suggests that non-agricultural sectors (particularly the service sector) have grown at the expense of agriculture However, as in all developing countries, about 72% (2001 Census) of India’s population still lives in rural areas The main source of income for this majority is either directly or indirectly dependent on agriculture Hence agricultural progress and stability, which has strong links to availability of water resources, holds the key to rural and agrarian prosperity in India 7.2.1 KEY DEVELOPMENT SECTORS AND WATER SOURCES In spite of a spurt in industrial growth and activity in the last 30 years, the livelihood of millions of people in rural India is still drawn from the agriculture sector Besides this, Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 157 there are also major linkages between agriculture and industry Agriculture supplies the raw materials for employment-intensive industries It stimulates and sustains industrial output through rural household demands for consumer goods and services It influences industry through government savings and public investment Besides irrigation supplies, large water reservoirs are also required to generate hydropower But unlike irrigation the consumptive use of water in this sector is mainly limited to the evaporative losses Many of the large reservoirs like Bhakra, Hirakud, Nagarjunasagar, Koyna, Pong, Rihand, Srisailam and Idduki are excellent examples of providing hydropower to the nation and have ushered the economic growth and prosperity to the region 70 35 30 20 75 o 80 o 85 o 90 o 95 o o o PA 25 o TA IS K N T I B E T o Myanmar o BAY OF BENGAL 15 o ARABIAN SEA > 2,000 m 1,000-2,000 m 10 500-1,000 m 0-500 m o Sri Lanka SCALE 500 KM Fig 7.1 Topographic Map of India The agricultural output is primarily governed by the availability of water making the country’s agrarian economy sensitive to the status of water resources and the monsoon in particular As the monsoons serve not only as a sole provider of water to large areas of Copyright © 2005 Taylor & Francis Group plc, London, UK 158 IMPLICATIONS FOR INDIA’S WATER RESOURCES rainfed cultivation but also remain the primary source of water to recharge the ground water resources of the country The demands on the water resources in the country, by the several sectors are not surprisingly dominated by the agriculture sector In the year 1999, agriculture consumed 85.3% of the water, industry 1.2%, energy sector 0.3% and other sectors 6.4% whereas domestic consumption was 6.6% (GOI, 2000) The two sources of freshwater are ground water and surface water; of these the river basins represent the main source of freshwater in the Indian subcontinent India is giftedwith a river system involving over 20 major rivers with many tributaries The total annual discharge in the rivers that flow in various parts of the country amounts to 1,880 km3yr-1 (CWC, 1995) Many of these rivers are perennial though few are seasonal The large rivers such as the Indus, the Ganges and the Brahmaputra have their origin in the Himalayas and flow throughout the year though their flows significantly reduce during the lean summer period (March to May) The Himalayan snow and ice supports three main river systems viz., Indus, Ganges and Brahmaputra having their average annual stream flow of 206 km2, 488 km2 and 510 km2 respectively Thus, more than 50% of water resources of India are located in various tributaries of these three river systems (Fig 7.2) Average water yield per unit area of the Himalayan Rivers is almost double that of South Peninsular river system indicating the importance of snow and glacier melt contribution from high mountains The average intensity of mountain glaciations varies from 3.4% for Indus to 3.2% for Ganges and 1.3% for Brahmaputra The tributaries of these river systems show maximum intensity of glaciations (2.5% to 10.8%) for Indus followed by Ganges (0.4% to 10%) and Brahmaputra (0.4% to 4%); the average annual and seasonal flows of these systems give a different picture thereby demonstrating that the rainfall contributions are greater in the Eastern region while the snow and glacier melt contributions are more important in the Western and Central Himalayan region Most of the rivers in South Peninsular India like the Cauvery, the Narmada and the Mahanadi are fed through ground water discharges (base-flow) and are supplemented by the monsoon rains Therefore, these rivers have very limited flow during the non-monsoon period The importance of these rivers lies not just in the size of their basins but also on the quantity of water they can carry The flow rate in these rivers is independent of the water source of the river and depends upon the precipitation rate in the region Therefore, in spite of being smaller in size, the rivers flowing West have a higher flow rate due to higher precipitation over that region Apart from the rivers, the Indian subcontinent is covered by a number of reservoirs, lakes, wetlands, mangroves and ponds During lean season, these reservoirs are the key source of water For example, a large dam in Mettur over Cauvery River has a 40 m high reservoir with a storage capacity of about 10 km3 The amount of water stored here during the monsoon season is released for irrigation under controlled conditions during the dry period Even though various types of freshwater bodies are widely distributed across the Indian subcontinent, still the availability of drinking water suggests skewed distribution of actual supply These water bodies regulate both the quantity and quality of water in addition to supporting the biota of various species The importance of these water bodies is apparent from the fact that in the thirteen States, which experienced frequent floods and drought in the last few years, 50% of the areas of those States are prone to periodic droughts possibly due to the shrinking or vanishing of these water bodies Many lakes in Rajasthan (including the largest lake in Udaipur) have been heavily silted and the water levels in the Krishnaraja reservoir in Tamil Nadu on the river Cauvery has gone down recently due to lack of water input from the upstream region Table 7.1 presents an overview of the storage capacity of various reservoirs in India Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 159 Fig 7.2 Major Rivers of India Table 7.1 Water storage capacity of reservoirs in India Reservoir’s storage at the end of monsoon 1998 1999 Reservoirs (number) Designed capacity (km3) Storage (km3) Average of last 10 years (km3) Current year’s storage as % of designed storage % of this year’s capacity to last 10 years 68 129 106 101 68 129 95 104 82 74 106 92 The ground water resources of the country are also vast Ground water acts as a regulating mechanism for storing water during wet season and thus it complements surface storage, which being location-specific may not be available The ground water level in the marshy and swampy Terai region of the Himalayas, the Northern most stretch of the Ganges basin, is only m-3 m below the ground surface, but it goes down drastically to 15 m-30 m below the surface in certain parts of the river basin The amount of freshwater that exists in Copyright © 2005 Taylor & Francis Group plc, London, UK 160 IMPLICATIONS FOR INDIA’S WATER RESOURCES this unconfined aquifer is massive and has not been brought into utilization in any systematic manner In fact, a good part of the dry season flow in the river system is augmented by the flow back of the ground water from the unconfined aquifers in the area adjoining the Ganges and its tributaries The deep artesian aquifers underlying millions of acres of alluvia and deltaic cropland in the Ganges basin are believed to be filled with freshwater to depths as great as 2,000 m The total replenishable ground water resource available in India is currently estimated to be 45.22 million hectare meter/year (mha m/yr) Of this quantity, 6.933 mha m/yr may be used for drinking and industrial purposes while the rest can be used for irrigation Interestingly, almost 80% of domestic water requirement in India today is met from ground water sources However, the ground water resources in several States of India are fast getting depleted primarily due to over extraction and poor recharging facility 7.2.2 THE NEED FOR SUSTAINABLE DEVELOPMENT OF WATER RESOURCES Despite the presence of substantial reserves of water in India, the actual utilizable quantity is limited and water crisis is seen to be inevitable in the future The annual quantity of freshwater including ground water available in India is currently about 1.88 km3 (CWC, 1995) This puts the per capita availability to be about 2,000 m3 i.e., 2x109 liters per person per year and this quantity is further expected to drop to 1,480 m3 in the next decade due to increase in population coupled with no further augmentation of water resources and also its consequent decrease over the same time due to consumption India will reach a state of water stress before 2025 when the availability falls below 1,000 m3 This clearly indicates the ‘two sided’ effect on water resources - the rise in population will increase the demand of water leading to faster withdrawal of water and this in turn would reduce the recharging time of the water tables As a result, availability of water is bound to reach critical levels sooner or later In this regard the emerging disputes are already indicative of what can be expected in the future Fights over water have already broken out in between States (Cauvery issue, Narmada problem, Krishna water disputes) Disputes between nations also already exist over sharing of river water between India and Bangladesh over the Ganges water and India and Pakistan over the Indus water Water riots have also been reported in Bhavnagar and Rajkot in Gujarat (Ramakrishnan, 1998) This makes it imperative to draw out appropriate action plans and strategies to conserve our water resources and optimize utilization of water from the various water sources 7.3 CLIMATE OF INDIA 7.3.1 PRESENT CLIMATE AND ITS SPATIAL DIVERSITY India, a country of subcontinental size, is the largest peninsula in the world and is surrounded by seas on the three sides with an extensive coastline of about 6,000 km Climatologically, India covers the tropical, sub-tropical and the temperate regimes The country is divided into almost two equal halves by the Tropic of Cancer The Northern half cutoff from the rest of the continent by the Himalayan range, experiences temperate type of climate whereas the extreme Southern part of the country falls within the tropical latitudes The inner Himalayas present sub-polar conditions registering extremely low and even negative temperatures in winter due to the altitude effect while the presence of the seas on all three sides brings the Southern Peninsular India under direct maritime influence with low diurnal temperature differences and a very moderate climate The interior of the Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 161 country experiences a continental type of climate with extreme annual temperature swings The summer temperatures over this region soar and often go beyond 40oC while the temperature in winter drops radically India’s unique geographical configuration gives it the peculiar climate regime with four seasons Winter season covering the months of December, January and February is followed by the summer (pre-monsoon) season extending from March to May India comes under the sway of the Southwest monsoon season from June to September and then goes through post-monsoon season from October to November The basic driving force behind the monsoons is the thermal contrast between the land and the sea During the pre-monsoon, as the sun progresses Northwards, a simultaneous shift in the converging zone of the trade winds of the two hemispheres (ITCZ) occurs to the North of the geographical equator The Southeasterly trades blowing in from the Southern Hemisphere get deflected to the right as they enter the Northern Hemisphere and blow into the subcontinent from the West Coast bringing with it moisture from the adjoining seas This marks the advent of the Southwest monsoon over the subcontinent The point of first entry of the monsoon in India is the Kerala Coast These Southwesterlies bring rain throughout the country, mainly to the South of the monsoon trough As the Southwest monsoon winds blow over peninsular India they collect more moisture from the Bay of Bengal and, on striking the Himalayan range in the North, get deflected Westward These deflected Southeasterly trades bring rains to the Northern half of the country As the summer monsoon enters from the Southwestern corner of the country, it moves progressively North and by 15th of July, it covers the entire Indian subcontinent (Fig 7.3) The monsoon circulation over the subcontinent is associated with several synoptic scale events such as the development of the heat low over Rajasthan in the Northwest India during the pre-monsoon season, the Tibetan high occurring over the Tibet plateau, the Mascarene high off the coast of Madagascar and the weakening of the sub-tropical Westerlies over North India with the subsequent onset of the tropical Easterly jet stream over the peninsular India Towards the end of the monsoon, as the sun begins its journey Southward the monsoon starts withdrawing This event is heralded by the reinforcement of the sub-tropical Westerlies over North India The Easterly jet disappears rapidly with the recession of the monsoons As the Westerly jet stream re-establishes itself South of the Himalayas, winter rains start to the Southeast coast near Tamil Nadu in India This is known as the Northeast or the winter monsoon During the winter months, rain also occurs over North India due to the Southward shift of the polar fronts Frontal or extratropical cyclones developing over West Asia and the Mediterranean Sea pass through North India during its passage Eastward The presence of the Himalayas weakens these disturbances and the temperature contrast of the air masses is also somewhat reduced because of which the frontal characteristic of these extra-tropical cyclones is not clearly evident Since these disturbances have their origin in the West, the rains which result over North India is said to be due to the Western disturbances The long-term average annual rainfall for the country as a whole is 116 cm - the highest for a land of comparable size in the world But this rainfall is highly variable both in time and space The percentage areal distribution of annual rainfall over India is given in Table 7.2 below The rainfall is highly variable in time as well The maximum rainfall occurs in July and August during the four-month (June to September) Southwest monsoon season There are considerable intra-seasonal and inter-seasonal variations as well The summer monsoon rainfall oscillates between active spells with good monsoon (above normal) on all India basis and weak spells or the breaks in the monsoon rains when Copyright © 2005 Taylor & Francis Group plc, London, UK 162 IMPLICATIONS FOR INDIA’S WATER RESOURCES deficient to scanty (≤20%) rains occur on all India basis for a few days at a stretch Weak and active spells of the summer monsoon is determined by the position of the monsoon trough extending from the Northwestern end over the Rajasthan desert to the head Bay of Bengal The monsoon trough oscillates either South or North of this normal position over the Gangetic plains When the trough is to the South or close to the normal position, active spells result and when it is near the foothills, weak monsoon conditions prevail The average seasonal summer monsoon rainfall of India is about 85 cm with a standard deviation of about ±10% Orissa, East Madhya Pradesh, West Bengal, and the Northeastern States of India, the Western coast and the Ghats receive more than 100 cm of rainfall during this season The submontane region extending from North Bihar to Jammu also receives more than 100 cm of rainfall The heavy rainfalls in the Northeastern States, West coast and the Ghats and the submontane regions are influenced by the orography The peninsular India South of 15oN gets less than 50 cm rainfall The lowest rainfall is received in the extreme Southeast Peninsula The West and the Northwest regions of the country receive about 50 cm of rain in the season The rainfall decreases rapidly to less than 10 cm in the West Rajasthan Regions above 50 cm in the season are classified as wet and those less than 50% as dry parts of India Fig 7.3 The onset and withdrawal dates of the Southwest monsoon The two monsoon seasons (the Southwest monsoon in June to September and the Northeast monsoon in November -December bring forth rains - many a times in intensities and amounts sufficient to cause serious floods creating hazardous (and often disastrous) situations Moreover, cyclonic storms in the pre-monsoon months (April-May) and the Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 163 post-monsoon months (October-November) cause large-scale inundation, destruction and deaths In fact, floods and cyclones are the two major natural disasters, which visit India quite often The adverse impacts of these two natural disasters cannot be assessed merely in economic terms based on destruction of crops, property and infrastructure because the toll of human misery in the form of death, disease, injury, loss of employment, psychological trauma, and above all the set-back to development are too difficult to evaluate Table 7.2 Areal Distribution (%) of Annual Rainfall over India Mean Annual Rainfall Corresponding % Area - 75 cm 75 - 125 cm 125 - 200 cm > 200 cm 30 % 42 % 20 % 8% An annual mean global warming of 0.4°C to 0.8°C has been reported since the late 19th century (IPCC, 2001) Surface temperature records indicate that the 1990s have been the warmest decade of the millennium in the Northern Hemisphere and 1998 is the warmest year (Fig 7.4) The observations also suggest that the atmospheric abundances of almost all greenhouse gases reached their highest values in recorded history during the 1990s (Nakicenovic et al., 2000) Anthropogenic CO2 emissions due to human activities are virtually certain to be the dominant factor causing the observed global warming In India, the analysis of seasonal and annual surface air temperatures (Pant & Kumar, 1997), using the data for 1881-1997, has shown a significant warming trend of 0.57oC per hundred years (Fig 7.5) The warming is found to be mainly contributed by the post-monsoon and winter seasons The monsoon temperatures not show a significant trend in any major part of the country except for a significant negative trend over Northwest India Similar trends have also been noticed in Pakistan, Nepal, Sri Lanka and Bangladesh The rainfall fluctuations in India have been largely random over a century, with no systematic change detectable on either annual or seasonal scale (Fig 7.6) However, areas of increasing trend in the seasonal rainfall have been found along the West Coast, North Andhra Pradesh and Northwest India and those of decreasing trend over East Madhya Pradesh, Orissa and Northeast India during recent years (Fig 7.7) The global warming threat is real and the consequences of the climate change phenomena are many, and alarming The impact of future climatic change may be felt more severely in developing countries such as India whose economy is largely dependent on agriculture and is already under stress due to current population increase and associated demands for energy, freshwater and food In spite of the uncertainties about the precise magnitude of climate change and its possible impacts particularly on regional scales, measures must be taken to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects 7.3.2 IMPACT OF GLOBAL WARMING ON INDIA’S CLIMATE Besides being the most important determinant of the economic welfare of the country, the monsoon is the predominant source of freshwater required for the rejuvenation of the water resources after the hot spell of the pre-monsoon season The leading concern today Copyright © 2005 Taylor & Francis Group plc, London, UK 164 IMPLICATIONS FOR INDIA’S WATER RESOURCES 1997 1998 1998 1997 1998 1997 1998 1997 1998 1997 1998 1998 1998 1997 1997 0.5 1997 0.6 1998 0.7 1991 0.8 1998 1990 0.9 1995 1998 1.0 1998 1988 Increase over 1880-1998 mean (oC) is the probable impacts that climate change and global warming might have on the annual cycle of the monsoon and the precipitation pattern A few of the currently available state-of-the-art Global Climate Models [CCSR/NIES (Japan), CSIRO (Australia), ECHAM (Germany) and UKMO (England) global climate models] have the ability to simulate the monsoon process realistically enough in order to be able to project the plausible regional climate change and its impacts on the long-term cycle of events including monsoons over the subcontinent (Lal & Harasawa, 2000) These models have been run with realistic forcing history for the 20th century and allow direct comparison of the model’s response to the observations The combination of the warming effects on a global scale from increasing 0.4 0.3 0.2 0.1 0.0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Month Fig 7.4 Monthly global mean temperature anomalies in the year 1998 and the previous warmest year 1.5 Linear Trend = 0.57ЊC/100 yrs Temperature Anomaly (ЊC) 0.5 -0.5 -1 5-Point Gaussian Lowpass Filtered -1.5 1881 1891 1901 1911 1921 1931 No of stations 1881-1900 25 1901-1990 121 1991-1997 30 1941 1951 1961 1971 1981 1991 Fig 7.5 All-India Mean Annual Surface Air Temperature Anomalies (1881-1997) Copyright © 2005 Taylor & Francis Group plc, London, UK 182 IMPLICATIONS FOR INDIA’S WATER RESOURCES conventional treatments and disinfections and therefore the total coliform count is allowed to be as high as 5,000, DO of mg/l or more and BOD of mg/l or less Water quality in the Class D is fit for wildlife The main criterion in this category is that the free ammonia should be less than 1.2 mg/l Water in Class E can only be used for irrigation and industry and must have electrical conductivity of less than 2,250 ìmhos/cm and a maximum sodium absorption ratio (SAR)1 of 26 The proper ratio of sodium ions to calcium and magnesium ions in irrigation water results in irrigated soil, which is granular in texture, easily worked, and permeable With increasing proportions of sodium as the SAR increases, soil tends to become less permeable and more difficult to work As per the standards laid down by CPCB, very few rivers in India meet the specifications of Class A except in the upper reaches of some rivers such as Beas Most of the rivers at selective points only are suitable for bathing such as at Rishikesh on the Ganges and at Rangantithu on Cauvery A number of water bodies such as the Sukhna Lake at Chandigarh and Ramgarh Lake at Udaipur come under Class C Rivers such as Cauvery at Tiruchirappalli and the Narmada River at Bharuch also come under this category Several water bodies in Bihar, Orissa, Maharashtra and Gujarat as well as the Rajmahal and Pichola Lake in Udaipur and certain locations along the Ganges such as Kanpur belong to Class D Certain lakes in Pondicherry and the Ganges at Varanasi fall in the category of Class E There are several water bodies that are totally unfit for use and are even below Class E such as Sabarmati at Ahmedabad, Asthamudi backwaters in Kerala, the creeks at the Elephant Caves Water quality of the surface waters in India as a whole is of concern as today a large amount of this resource is unfit for one or the other type of uses Being centers of intense human activity and also due to high population density in the catchment areas, most of the river basins especially the larger ones such as the Ganges and the Brahmaputra are polluted Therefore, in spite of the presence of large perennial rivers, poor quality of water in the rivers restricts our options for utilizing these sources of water Problems of water quality aggravate during the lean season due to poor dilution of pollutants and are intensifying due to reduced flows in the rivers This can become more critical for the rainfed rivers in the years when the monsoon fails The existence of promising potentials of freshwater lies in our rivers However, due to lack of proper management of rivers in India, the country is already on the brink of water stress The reintroduction and the recent emphasis which is being laid on the traditional ideas of rain water harvesting and augmenting recharging of ground water using defunct bore wells holds immense potential and will definitely assist in alleviating water stress But sole reliance on these options may not completely solve the problem of water at the present or in the future as these options too have their drawbacks such as availability of large land areas and also there dependence on precipitation which is subject to large intra-seasonal and inter-annual fluctuations Despite environmental and social disturbances caused by big dams, we may not be able to ensure food security and a reliable water supply of the country without implementation of large hydrological projects The fall out of these projects can be managed and damages may be minimized and feasibility of such projects entertained through cost benefit analysis including environmental and social costs The need for such projects are emphasized by the fact that that the entire water supply of Mumbai, Pune, Hyderabad and Warangal cities is dependent on a series of dams like Vaitarana, Tansa, Bhatsa, Khadakwasla, Panset, Majira, Singur and Sriramsagar dams The cluster of thermal and super thermal power stations in Uttar Pradesh is entirely dependent on the SAR = Na+/((Ca+2+Mg+2)/2)0.5 Copyright © 2005 Taylor & Francis Group plc, London, UK Table 7.8 Water Quality Standards for different users* Class of Water Criteria Some Examples from Rivers in India Drinking water source without conventional treatment but after disinfections A Total Coliforms Organism MPN/100ml shall be 50 or less pH between 6.5 and Dissolved Oxygen 6mg/l or more Biochemical Oxygen Demand 20°C 2mg/l or less Beas at Manali, Himachal Pradesh Ravi at Madhopur, Himachal Pradesh Outdoor bathing (organized sector) B Total Coliforms Organism MPN/100ml shall be 500 or less pH between 6.5 and 8.5 Dissolved Oxygen 5mg/l or more Biochemical Oxygen Demand 20°C 3mg/l or less Ganges at Reshikesh, Uttar Pradesh Tapi at Nepanagar, Madhya Pradesh Drinking water source after conventional treatment and disinfections C Total Coliforms Organism MPN/100ml shall be 5000 or less pH between to Dissolved Oxygen 4mg/l or more Biochemical Oxygen Demand 20°C 3mg/l or less Achankoli at Thumpaman, Kerala Cauvery at Napokulu Barrage, Karnataka Propagation of wild life and fisheries D pH between 6.5 to 8.5 Dissolved Oxygen 4mg/l or more Free Ammonia (as N) 1.2 mg/l or less Brahmani at Panposh, Orissa Brahmaputra at Dibrugarh, Assam Irrigation, industrial cooling, controlled waste disposal E pH between 6.0 to 8.5 Electrical Conductivity at 25°C micro mhos/cm Max 2250 Sodium absorption Ratio Max 26 Boron Max 2mg/l Mahi at the confluence of River Chap Gujarat Sabarmati at Miroli Village, Gujarat M LAL Designated Best-Use *Source: Data from Central Pollution Control Board, 1996 183 Copyright © 2005 Taylor & Francis Group plc, London, UK 184 IMPLICATIONS FOR INDIA’S WATER RESOURCES storage of Rihand Dam for their water supply Therefore the need for such projects is urgent in order to meet the demand for the future and more so as the present utilizable water resources have already been exploited to the limit The Himalayan river system holds immense potential as a future freshwater source The Himalayan snow and ice supports three major main river systems viz., Indus, Ganges and the Brahmaputra having an average annual stream flow of 206 km3, 488 km3 and 510 km3 respectively Thus, almost 50% of our water resources of our country are located in the various tributaries of these three river systems Apart from monsoon rains, India has been using the Himalayan Rivers for over a century for its water resource development In recent decades, the hydrological characteristics of the watersheds in this region seems to have undergone substantial change as a result of extensive land-use (e.g., deforestation, agricultural practices and urbanization) leading to more frequent hydrological disasters, enhanced variability in rainfall and runoff, extensive reservoir sedimentation and pollution of lakes, etc The global warming and its impact on the hydrological cycle and nature of hydrological events have posed an additional threat to this mountainous region of the Indian subcontinent Extreme precipitation events have geo-morphological significance in the Himalayas where they may cause widespread slope failures (Ives & Messerli, 1989) The issue of the response of hydrological systems, erosion processes and sedimentation in this region could alter significantly due to climate change The Himalayas have nearly 1,500 glaciers and it is estimated that these cover an area of about 33,000 km2 These glaciers provide the snow and the glacier melt waters keep our rivers perennial throughout the year The most useful facet of glacier runoff is the fact that glaciers release more water in a drought year and less water in a flood year and thus ensuring water supply even during the lean years The snow line and glacier boundaries are sensitive to changes in climatic conditions Almost 67% of the glaciers in the Himalayan mountain ranges have retreated in the past decade (Ageta & Kadota, 1992; Yamada et al., 1996; Fushimi, 2000) The mean equilibrium line altitude at which snow accumulation is equal to snow ablation for glacier is estimated to be about 50 m-80 m higher relative to the altitude during the first half of the 19th century (Pender, 1995) Available records suggest that Gangotri glacier is retreating about 30 m/yr A warming is likely to increase the melting far more rapidly than the accumulation Glacier melt is expected to increase under changed climate conditions, which would lead to increased summer flows in some river systems for a few decades, followed by a reduction in flow as the glaciers disappear (IPCC, 1996) The Ganges River basin is capable of providing sufficient quantity of freshwater to accommodate the future demands The river basin is as huge as the combined area of France, Germany and Belgium The maximum discharge of the river, often attained during the month of September, is close to 60,232 m3/sec; this drops to a minimum discharge of 1,743 m3/sec during the peak of the dry season What is evident from this disparity in flow is that we can harvest Ganges water when its flow is high and then increase its minimum discharge during the dry season significantly and thereby manage the demand for a consistent water supply This will also provide a sustainable supply of water for our agriculture, domestic and industrial needs 7.5.2 GROUND WATER POTENTIALS In many regions due to the absence of an alternative or reliable source, ground water is the main source of water Ground water is the principle source of drinking water in the rural habitations of the country and almost 85% of the rural water supply is dependent on ground water India on the whole has a potential of 45.22 mha m/yr of replenishable ground water Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 185 Unfortunately, due to rampant drawing of the sub-surface water, the water table in many regions of the country has dropped significantly in recent years resulting in threat to ground water sustainability These regions mainly correspond to the States that have registered ground water development above the national average The States include Gujarat, Punjab, Haryana, Tamil Nadu and Rajasthan The situation in Gujarat, in particular, is critical The water table in Ahmedabad is reported to be going down at the rate of m to m every year In some localities of Delhi, the water table has fallen by over 10 m Even in Kerala, where the intensity of monsoon rain is heavy, water table has been falling systematically in all parts of the State Gujarat has developed 41% of its ground water resources as compared to the all India average of 32% About 90% of the ground water is currently used for irrigation facilities According to government sources, the water table has registered a net fall in the level of water table for the nation as a whole in the year 1999 (Table 7.9) The water quality of sub-surface water is interlinked with quantity Overexploitation of ground water has resulted in a drop in its level leading to ingress of seawater in coastal areas making the sub-surface water saline India is especially susceptible to increasing salinity of its ground water as well as its surface water resources especially along the coast due to increase in sea level as a direct impact of global warming Increase in sea level leads to intrusion of saline water far into the land mass through the rivers draining into the sea and it also increases ground water contamination by making water saline Saline water Copyright © 2005 Taylor & Francis Group plc, London, UK 186 IMPLICATIONS FOR INDIA’S WATER RESOURCES cannot be used for either agriculture or fishery development Lower levels of water due to excess withdrawing have also led to deterioration of water quality Several problems of arsenic and fluoride contamination in water have surfaced in certain parts of the country High levels of fluoride in water has led to acute cases of flourosis in many villages of Andhra Pradesh, Ajmer in Rajasthan, Gurgaon District in Haryana, Salem in Tamil Nadu and some villages in Agra in Uttar Pradesh Arsenic problem is rampant in West Bengal and has given rise to acute health problems in the State More than 7,000 wells in several districts in West Bengal have high dissolved arsenic usually more than 50 µg/l today The ground water resources may still have large potentials for the future Apart from being a major source of sub-surface water, the vast body of water carried by the Ganges and the heavy rainfall experienced in the valley and the mountains in the North has created another source of water wealth The ground water level in the marshy and swampy Terai region of the Himalayas and the Northern stretch of the Ganges basin is only m-2.5 m below the ground surface, though it goes down drastically to 15 m-30 m below the surface in certain parts of the river basin The amount of water that exists in this confined aquifer is massive and has not been brought into utilization in any systematic manner In fact, a good part of the dry season flows in the river area adjoining the Ganges and its tributaries is augmented by the flow back of ground water from this aquifer In the Terai region, the aquifer never drains and it has already become a huge deep aquifer A study by the World Bank (Chitale, 1992) shows that the ground water resources available for the development in South Asia beneath the alluvia and deltaic plains, in deeper and regionally extensive confined aquifers is so large that it cannot be accounted for accurately These artesian aquifers are filled with freshwater to a depth as great as 2,500 m Water in deep aquifers is naturally replenished from the surface sources These deep aquifers are artesian and they often produce water through wells without pumping This would decrease at least the direct operational cost and would also cost significantly less than the surface irrigation projects to supply water to the same area Moreover, the drinking water of deep aquifers is less likely to be contaminated by agricultural chemicals and other pollutants as water in these aquifers have accumulated there after passing through thick sediment column, which is perhaps the most effective filtering system Therefore, sustainable use of this huge resource is a feasible option 7.5.3 POTENTIAL OF THE MONSOONS TO SUPPLEMENT WATER SUPPLY Over the last one hundred years or so, we have seen two paradigmatic shifts in water management in India One is that individuals and communities have steadily given over their role almost completely to the States This dependence on the State has meant cost recovery being poor the financial sustainability of water schemes has run aground; and, repairs and maintenance is abysmal With people having no interest in using water carefully, the sustainability of water resources has itself become a question mark As a result, there are serious problems with government’s drinking water supply schemes Despite all the government efforts, the number of ‘problem villages’ does not seem to go down The second is that the simple technology of using rainwater has declined Instead exploitation of rivers and ground water through dams and tube wells has become the key source of water As water in rivers and aquifers is only a small portion of the total rainwater availability, there is an inevitable growing and, in many cases, unbearable stress on these sources Keeping in view the huge demand on the water resources and the present state of our water sources, alternatives must be devised to supplement the present reserves of Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 187 freshwater and reduce over exploitation such that the system of extraction is sustainable Micro-watershed development is the most viable method of harnessing water by cheaper, quicker and safer means This is basically an approach to conserve land and water in which natural and human resources can be dovetailed and deployed to ensure food, fodder, fuel, fruits and fiber In watershed planning, the basic principle is using land according to its capability and water according to its availability In this scheme effective moisture conservation holds the key The three parameters are rainfall, runoff and recharge The vegetation cover of grass and trees has a vital role in retarding the runoff and allowing maximum recharge In order to sustain the available water resources in a region, the key factors that must be taken into consideration include (i) water availability, (ii) favorable topography, (iii) physiography and hydrogeological setup, (iv) infiltration and percolation characteristics of vadose zone, (v) hydrologic characteristics of the aquifers such as capacity to store, transmit and yield water, and (vi) techno-economic feasibility Various technological options for ground water recharge keeping in view the local conditions must also be explored Today the major problem seems to be the paucity of drinking water in almost all urban centers of India In order to supplement the domestic water requirement, harvesting of the water received, as rain is a wise option India receives 400 mha meters of precipitation every year and it is estimated that nearly 70 mha meter of this water evaporates immediately from the soil and about 105 mha meter flow out to the sea After allowing for all the hydrological processes, the total utilizable potential is about 105 mha meter though less optimistic estimates put it at 86 mha meter-92 mha meter The use of the traditional systems of water harvesting to catch and store water is a feasible option but it may not be adequate to meet the rising demand of water for industrial, agricultural and energy purposes However, the rooftop water harvesting would be a good supplementary source of water for domestic purposes primarily to meet the demand of water for cooking and drinking The rooftop harvesting approach could also enhance the recharging potentials of the aquifers by allowing water to sink into the ground through the new bore wells and through the use of defunct bore wells as well However, the effectiveness of these options is subject to the eccentricities of the climatic conditions and a poor monsoon could seriously affect the potentials of these options The climate change will affect the spatial and temporal distribution of surface water, soil moisture and ground water resources Precipitation and temperature are the two key variables affecting the availability and demand for water However, future projections of likely changes in monsoon rainfall and its spatial and temporal variability over India as presented above have rather low confidence due to limitations of the currently available global climate models None-the-less, it has been suggested that there is no village in India that cannot meet its basic drinking and cooking needs through rainwater harvesting For example, the average population is about 1,200 in an Indian village today India’s average annual rainfall is about 1,100 mm If even only half this water can be captured, an average Indian village needs 1.2 hectares of land to capture 6.57 million liters of water it can use in a year for cooking and drinking In case of a drought or poor monsoon even if the rainfall levels dip to half the normal, the land required would rise to a mere 2.4 hectares Thus, a mass movement for rainwater harvesting could perhaps provide a lasting relief against droughts in many States of India Community-based rainwater harvesting in India - the paradigm of the past - has in it as much strength today as it ever did before Copyright © 2005 Taylor & Francis Group plc, London, UK 188 IMPLICATIONS FOR INDIA’S WATER RESOURCES 7.6 FUTURE DEMAND AND SUPPLY OF WATER 7.6.1 WATER DEMAND At present, available statistics on water demand shows that the agriculture sector is the largest consumer of water About 85% of the available water is used for agriculture alone The quantity of water required for agriculture has increased progressively through the years as more and more area was brought under irrigation In 1950, a total area of 25 x 106 hectares was under irrigation and this has increased over folds in decades The contribution of surface and ground water resources for irrigation has played a significant role in India attaining self-sufficiency in food production during the past decades and is likely to become more critical in future in the context of national food security According to available estimates, the demand on water in this sector is projected to decrease to about 74% by the year 2050 though agriculture will still remain the largest consumer In order to meet this demand, augmentation of existing water resources by development of additional sources of water or conservation of the existing resources through impounding more water in the existing water bodies and its conjunctive use will be needed Water demand in the other sectors is also expected to increase significantly (Table 7.10) The water demand for the energy sector is likely to increase dramatically, almost 70 times by the year 2050 This may be associated with the rapid growth in industry and urbanization The projected share of demand by the energy sector would most likely be about 8.9% in the year 2050 as against the present share of 0.3% The demand of water in the industry sector could increase folds during the same period The water demand can be expected to increase to 4.3% in the year 2050 as against 1.2% for this sector, which is poised for rapid expansion in the decades to come Table 7.10 Water availability and demand in next 50 years Sector 2000 Year 2025 2050 Domestic Irrigation Industry Energy Other 42 541 41 73 910 22 15 72 102 1,072 63 130 80 Total 634 1,092 1,447 As the population increases, there will also be a corresponding increase in the demand for water in the domestic sector The demand for domestic water is likely to increase from the present-day 6.6% to 7.0% in 2050 Even at present, at least part of the urban populations in many States not have access to drinking water In certain States like Assam, the percentage of urban population with an access to drinking water is only 10% and in Tamil Nadu it is 50% The other States that are currently facing problems of inadequate drinking water include Kerala, Andhra Pradesh, Bihar, Goa, Orissa, West Bengal, Punjab and the Northeastern States of Meghalaya, Mizoram, Manipur, Tripura and Sikkim Based on available statistics, the per capita daily water availability in India is expected to drop from 600 liters per day in 1990 to a critical level of 300 liters per day by Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 189 2030 The per capita water available in the capital city of Delhi is nearing the critical level (Zerah, 2000) while the actual amount for Delhi is already below the critical level The fall in per capita water availability will, however, not be uniform throughout the country For instance, based on the data on the per capita availability of water for the last fifty years, projections have been made for the next fifty years The national average in the year 2000 has been projected to be 2.5 x 103 m3/yr/person The corresponding availability of water for the Northeastern region was reported as 18.4 x 103 m3/yr/person which is much higher than the national average The per capita availability in the Southern part of the country and Tamil Nadu, in particular, is however lower than the national average and is about 0.4 x 106 m3/yr/person (Suresh, 2000) Projections made on the global scale suggests that with the increase in population and potential climate change the per capita water availability is likely to decrease by 34% in 2025 to 48% in 2080 relative to the present availability of water (Jones et al., 1999) 7.6.2 LONG-TERM WATER SUPPLY PROSPECTS In order to fulfill such demands in the future, we will need to rationalize on the various means of capturing and storing water Harvesting of rainwater should contribute to meeting the future water requirements sustainability in India But the increase in the corresponding demand in the energy sector, industrial as well as increased demand in irrigation will require more water than can be harvested from rainfall alone The inter-annual variability of the monsoons is expected to increase in the future making the monsoons less reliable as an assured source of water Therefore, efforts are needed for more efficient ground water recharge and harvesting of rainwater through identification, adoption and adaptation of technological options Some of the structural activities such as Nalla bunds, contour bunds, contour trenches, gully plugs, check dams, pits and shafts, basin percolation tanks, surface channels, ground water dams, injection wells, connector wells, storage tanks, dug well recharge, bore hole flooding, ditch and furrow, stream augmentation, de-silting of existing tanks and inter-watershed transfer should be tried depending on local conditions Restoration, revival, revitalization and upgrading of existing/traditional rainwater harvesting structures would ensure sustainability of water resources Much of the future demand will need to be met from the ground water resources which may have immense potential The water potential of the Ganges valley can irrigate an additional 200 mha of land which can sustain rice productivity of about tons per hectare and can produce another 80 million tons of rice that can sustain another 350 million-400 million people (Singh, 1995) The excess water requirement in the future can, however, only be made through properly planned and precise management Studies carried out for the Ganges basin need to be conducted for all major river basins in the country in order to discover additional potential sources of water such as deep artesian aquifers 7.7 GOVERNMENT POLICY AND LEGISLATIVE TOOLS The increasing demand of water and its reduced availability is a growing national concern Projections of water stress in the near future are rapidly turning into stark reality Yet, all said and done, India till date has not been able to adequately handle the problem of water quantity and quality As a result, water shortage is being felt all over the country A number of legislative tools to protect the national water resources exist but these have had no Copyright © 2005 Taylor & Francis Group plc, London, UK 190 IMPLICATIONS FOR INDIA’S WATER RESOURCES significant impacts due to poor implementation The Water Pollution Act of 1972 was primarily introduced to prevent the deterioration of water quality Its implementation as with all other Environmental Acts has been lax and pollution of water sources is going on unhindered The National Water Policy of 2002 declared water to be a scarce and a precious natural resource to be developed and conserved on an integrated and environmentally sound basis The emphasis has been appropriately laid on the end use of water Efforts are underway to increase the efficiency of utilization of water by the several sectors There also exists a Supplementary Act to the Water Pollution Act of 1972, known as the ‘Water Cess Act’ by which industries consuming above a certain quantity of water are to pay higher taxes on the water consumed by them These laws are in keeping with the water policy of the country but the cost of water has not been accurately assessed due to which water has been grossly under priced and the very purpose of the Act is defeated It is economically more feasible for the industries to pay the amount rather than to install and operate recycling or treatment plants Water in many parts of the country is still almost free of cost Due to the low price of water there is rampant abuse of this resource Water supplied for irrigation is a case in point The negligible amount charged for irrigation has resulted in widespread overuse resulting in a perpetual flooding condition of croplands and the loss of fertile land A World Bank study on subsidies offered by governments on water has reported that it fails to benefit the poorer sections of the population In fact the poor end up paying a higher price for water as they not have access to the government supply and are forced to purchase water from commercial vendors Due to lack of sufficient incentives, the industries have failed to respond to the growing need of reuse and recycling of wastewater There also exists a lacunae in national policy to involve individuals in conserving water Though several NGOs of the country are encouraging the people to take the initiative to harvest rainwater and promoting the cause of water conservation at the grass root level, the government has not yet adequately moved in this direction Major initiatives need to be taken by the government to plan and implement water resource conservation programmes Keeping in mind the plausible impacts of global warming on our water resources, the government has to come up with appropriate guidelines and action plans for water conservation for the future Without such initiatives, the water crises in India are likely to increase in the future 7.8 COPING WITH CLIMATE CHANGE AND ADAPTATION Climate change is just one of a number of factors influencing the hydrological system and water resources Population growth, changes in land-use, restructuring of the industrial sector, and demands for ecosystem protection and restoration are all occurring simultaneously Current policies affecting water use, management, and development are often contradictory, inefficient, or unresponsive to changing conditions In the absence of explicit efforts to address these issues, the societal impacts of water scarcity in India are likely to rise as competition for water use grows and supply and demand conditions change A change in drought or flood risks is one of the potential effects of climate change with the greatest implications for human well-being Few studies have looked explicitly at the implications of climate change for drought or flood frequency, in large part because of the lack of detailed regional precipitation information from global climate models Higher average or a greater range of flows of water could reduce pollutant concentrations or increase erosion of land surfaces and stream channels, leading to more Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 191 sediment and greater chemical and nutrient loads in rivers and coastal deltas Lower average flows could reduce dissolved oxygen concentrations, reduce the dilution of pollutants and reduce erosion For almost all water bodies, land-use and agricultural practices have a significant impact on water quality Changes in these practices, together with technical and regulatory actions to protect water quality, can be critical to future water conditions Key Messages for Water Resource Planners Climate is not static and assumptions made about the future based on the climate of the past may be inappropriate Assumptions about the probability, frequency, and severity of extreme events used for planning should be carefully re-evaluated Climate changes will be imposed on top of current and future non-climate stresses In some cases, these changes will be larger than those expected from population growth, land-use changes, economic growth, and other non-climate factors Certain threshold events may become more probable and non-linear changes and surprises should be anticipated, even if they cannot be predicted with a high degree of confidence The time lags between identifying the nature of the problems, understanding them, prescribing remedies, and implementing them are long Waiting for relative certainty about the nature of climate change before taking actions to reduce climate change related risks may prove far more costly than taking certain pro-active management and planning steps now Methods must be used that explicitly incorporate uncertainty into the decision process Expensive and long-lived new infrastructures should consider a wider range of climate variability than provided by the historical record into infrastructure designs There are many opportunities to reduce the risks of climate variability and change for India’s water resources Past efforts have focused on minimizing the risks of natural variability Many of the approaches for effectively dealing with climate change are different than the approaches already available to manage risks associated with existing variability Tools for reducing these risks have traditionally included supply-side options such as new dams, reservoirs, and more recently improving efficiency This is largely independent of the issue of climate change, which will have important implications for the ultimate severity of future water stresses Sole reliance on traditional management responses should be avoided First, climate change is likely to produce - in some places and at sometimes - hydrologic conditions and extremes of a different nature than current systems were designed to manage; second, climate change may produce similar kinds of variability but outside of the range for which current infrastructure was designed and built; third, relying solely on traditional methods assumes that sufficient time and information will be available before the onset of large or irreversible climate impacts to permit managers to respond appropriately; and fourth, this approach assumes that no special efforts or plans are required to protect against surprises or uncertainties Copyright © 2005 Taylor & Francis Group plc, London, UK 192 IMPLICATIONS FOR INDIA’S WATER RESOURCES The first situation could require that completely new approaches or technologies be developed The second could require that efforts above and beyond those currently planned or anticipated be taken Complacency on the part of water managers, represented by the third and fourth assumptions, may lead to severe impacts that could have been prevented by cost-effective actions taken now As a result, we make the following observations and recommendations: • • • • • • • • • Prudent planning requires that a strong national climate and water monitoring and research program should be developed, that decisions about future water planning and management be flexible, and that expensive and irreversible actions be avoided in climate-sensitive areas Better methods of planning under climate uncertainty should be developed and applied Decision makers at all levels should re-evaluate technical, and economic approaches for managing water resources in view of potential climate changes The government should ask all States managing national water systems to begin assessing both climate impacts and the effectiveness of different operation and management options Improvements in the efficiency of end uses and the management of water demands must now be considered major tools for meeting future water needs, particularly in water-scarce regions Water demand management and institutional adaptation are the primary components for increasing system flexibility to meet uncertainties of climate change Water managers should begin a systematic re-examination of engineering designs, operating rules, contingency plans, and water allocation policies under a wider range of climate conditions and extremes than have been used traditionally For example, the standard engineering practice of designing for the worst case in the historical observational record may no longer be adequate Cooperation between water agencies and leading scientific organizations can facilitate the exchange of information on the state-of-the-art thinking about climate change and impacts on water resources The timely flows of information among the climate change scientists and the water-management community are valuable Such lines of communication need to be developed Traditional and alternative forms of water supply can play a role in addressing changes in both demands and supplies caused by climate changes and variability Options to be considered include wastewater reclamation and reuse, rainwater harvesting and even limited desalination where less costly alternatives are not available None of these alternatives, however, is likely to alter the trend toward higher water demand in the future Prices and markets are increasingly important for balancing supply and demand Because new construction and projects can be expensive, environmentally damaging, and politically controversial, the proper application of economics and water management can provide incentives to use less and produce more Among the new tools that need to be explored are water banking and conjunctive use of ground water Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 7.9 193 RESEARCH NEEDS Records of past climate and hydrological conditions are no longer considered to be reliable guides to the future The design and management of both structural and non-structural water-resource systems should allow for the possible effects of climate change, but little professional guidance is available in this area Further research by hydrologists, civil engineers, water planners, and water managers is needed to fill this gap, as is broader training of scientists in the universities • • • • • • • • • 7.10 More work is needed to improve the ability of global and regional climate models to provide information on water-resources availability, to evaluate overall hydrologic impacts, and to identify regional impacts Substantial improvements in methods to downscale climate information are needed to improve our understanding of small-scale processes that affect water resources and water systems Information about how our summer monsoon will be affected due to climate change is vitally important for determining impacts on water and water systems, yet such information is still not reliably available More research on how the severity of cyclones and other extreme hydrologic events might change is necessary Increased and widespread hydrologic monitoring systems are needed There should be a systematic re-examination of engineering design criteria and operating rules of existing dams and reservoirs under conditions of climate change Information on economic sectors most susceptible to climate change is extremely weak, as is information on the socioeconomic costs of both impacts and responses in the water sector More work is needed to evaluate the relative costs and benefits of non-structural management options, such as demand management and water-use efficiency in the context of a changing climate Research is needed on the implications of climate change for international water treaties and agreements with Nepal and Bangladesh Little information is available on how climate changes might affect ground water aquifers, including quality, recharge rates, and flow dynamics New studies on these issues are needed CONCLUDING REMARKS There are two distinct but complementary approaches to address the problem of water resources in a holistic manner They are: (i) (ii) Augmenting and enhancing the present reserves Taming the end demand Sustainable use of water resource gets increasingly difficult as the demand for water far exceeds the availability, and the discounting rates for the future tends to increase under such circumstances Therefore, in order to make our water utilization more sustainable both these approaches will have to be followed Though India is endowed with extensive sources of water, the utilizable quantity is less as the full potential of our rivers has not yet been assessed accurately (as is evident Copyright © 2005 Taylor & Francis Group plc, London, UK 194 IMPLICATIONS FOR INDIA’S WATER RESOURCES from the study of water potential of the Ganges basin) neither has there been proper river management programme The present water availability is further restricted due to water pollution as well as increasing salinity which has rendered several of our river water as well as ground water unfit for one or the other type of use In order to meet the future demand of water in a sustainable manner, emphasis has appropriately been laid in recent years on the implementation of rainwater harvesting as well as rooftop harvesting of rainwater But these options are limited in their capacity to meet the burgeoning national demand of water as they are subject to the variability of the monsoon, which is projected to increase due to global warming These steps would be most effective at the grass root level in meeting the demands of the rural population without having to depend on the government for the required infrastructures and would help in supplementing the main water supply In spite of the increase in the anti-dam sentiments in the country, it is considered irrational to rule out the hydrological projects completely It would be otherwise impossible to ensure food security and supply of water for energy and industrial sectors These projects would also increasingly reduce our dependence on the monsoons as the precipitation patterns over the country become more erratic due to climate change So we will have to rationalize on the options available to us and make the best use of our resources The other end of the water problem is to increase the efficiency of the end use of water The water policy of the country has been rightly oriented in this regard but implementation of the policy has been far from satisfactory The water demand has to be tamed through an appropriate conjunction of economic as well as legislative mechanisms REFERENCES Ageta, Y and Kadota, T.: Prediction of Change of Mass Balance in the Nepal Himalayas and Tibetan Plateau: A Case Study of Air Temperature Increase for Three Glaciers Annals of Glaciology 16 (1992), pp.89-94 Asian Development Bank: Key Statistics, ADB, Manila, 2003 Bagchi, K S.: Drought Prone India: Problems and Perspectives, Vol I & II, Agricole Publishing Academy, New Delhi, 1991 Boer, G J., Flato, G., Reader, C and Ramsden, D.: A Transient Climate Change Simulation with Greenhouse Gas and Aerosol Forcing Projected Climate for the 21st Century Climate Dynamics 16 (1999), pp.405-425 CPCB (Central Pollution Control Board): Annual Report 1995-1996, New Delhi, 1996, p.165 CWC (Central Water Commission): Water and Related Statistics, New Delhi, 1995 CDBI (Climate Diagnostic Bulletin of India): Post-Monsoon 1999, Special Issue No 15, National Climate Center, India Meteorological Department, Pune, 1999, p.20 Chitale, M A.: Water Resource Management in India - Achievements and Perspectives, World Bank Technical Paper No 175, 1992 Collins, M.: The El-Niño Southern Oscillation in the Second Hadley Center Coupled Model and Its Response to Greenhouse Warming J Climate 13 (1999), pp.1299-1312 Emanuel, K A.: The Dependence of Hurricane Intensity Nature 329 (1987), pp.483-485 Emanuel, K A.: Toward a General Theory of Hurricanes Am Sci 76 (1988), pp.371-379 Emanuel, K A.: Thermodynamic Control of Hurricane Intensity Nature 401 (1999), p.665 Copyright © 2005 Taylor & Francis Group plc, London, UK M LAL 195 Fushimi, H.: Recent Changes in Glacier Phenomena in the Nepalese Himalayas In A Domoto, K Iwatsuki, T Kawamichi and J McNeely (eds.) A Threat to Life: The Impact of Climate Change on Japan’s Biodiversity, Tsukiji-Shokan Pub Co., Ltd., Japan and The World Conservation Union (IUCN), Gland, Switzerland and Cambridge, U.K., 2000, pp.42-45 Gray, W M.: Hurricanes: Their Formation, Structure and Likely Role in the Tropical Circulation, In Shaw D B (ed), Meteorology over Tropical Oceans, Royal Meteorological Society, Bracknell, 1979, pp.155-218 GOI (Government of India): Compendium of Environmental Statistics, Ministry of Statistics and Programme Implementation, New Delhi, 1999, p.228 GOI (Government of India): Yearbook, Published by Ministry of Information and Publication, New Delhi, 2000 Goel, R S (ed.): Environmental Impacts of Water Resources Development, Proc of the National Round Table Discussion in New Delhi, June 4-5, Tata McGraw-Hill Publishing Company Ltd., 1993, p.359 Henderson-Sellers, A., Zhang, H., Berz, G., Emanuel, K., Gray, W., Landsea, C., Holland, G., Lighthill, J., Shieh, S-L, Webster, P and McGuffie, K.: Tropical Cyclones and Global Climate Change: A Post IPCC Assessment Bull Amer Meteorol Soc 79 (1998), pp.19-38 IPCC (Intergovernmental Panel for Climate Change): Climate Change 1995: The Science of Climate Change Contribution of Working Group I to the Second Assessment Report of the Intergovernmental Panel on Climate Change In J J Houghton, L G Meiro Filho, B A Callander, N Harris, A Kattenberg and K Maskell (eds.), Cambridge University Press, Cambridge and New York, 1996, p.572 IPCC (Intergovernmental Panel for Climate Change): Climate Change 2001: The Scientific BasicsSummary for Policymakers and Technical Summary of the Working Group I Report, IPCC, Geneva, 2001 Ives, J D and Messerli, B.: The Himalayan Dilemma: Reconciling Development and Conservation, Routledge, London, 1989 Jones, R N., Hennessy, K J., Page, C M., Pittock, A B., Suppiah, R., Walsh, K J E and Whetton, P H.: An Analysis on the Effects of the Kyoto Protocol on Pacific Island Countries, Part Two: Regional Climate Change Scenarios and Risk Assessment Methods CSIRO Atmospheric Research Report to the South Pacific Regional Environment Programme, 1999, p.69 Kitoh, A., Yukimoto, S., Noda, A and Motoi, T.: Simulated Changes in the Asian Summer Monsoon at Times of Increased Atmospheric CO2 Jr Meteor Soc Japan 75 (1997), pp.1019-1031 Knutson, T R and Manabe, S.: Model Assessment of Decadal Variability and Trends in the Tropical Pacific Ocean J Climate (1998), pp.2273-2296 Knutson, T R., Tuleya, R E and Kurihara, Y.: Simulated Increase of Hurricane Intensities in a CO2Warmed Climate Science 279 (1998), pp.1018-1020 Krishnamurti, T N., Correa-Torres, R., Latif, M and Daughenbaugh, G.: The Impact of Current and Possibly Future SST Anomalies on the Frequency of Atlantic Hurricanes Tellus 50A (1998), pp.186-210 Kulshrestha, S M.: Drought Management in India and Potential Contribution of Climate Prediction, Joint COLA/CARE Technical Report No 1, Maryland, USA, 1997, p.105 Lal, M., Cubasch, U and Santer, B.D.: Effect of Global Warming on Indian Monsoon Simulated with a Coupled Ocean-Atmosphere General Circulation Model Current Science 66(6) (1994), pp.430-438 Lal, M., Cubasch, U., Voss, R and Waszkewitz, J.: Effect of Transient Increases in Greenhouse Gases and Sulphate Aerosols on Monsoon Climate, Current Science 69(9) (1995), pp.752-763 Lal, M and Harasawa, H.: Comparison of the Present-Day Climate Simulation Over Asia in Selected Coupled Atmosphere-Ocean Global Climate Models Jr Meteor Soc Japan 78(6) (2000), pp.871-879 Lal, M and Harasawa, H.: Future Climate Change Scenarios for Asia as Inferred from Selected Coupled Atmosphere-Ocean Global Climate Models Jr Meteor Soc Japan 79(1) (2001) Lal, M., Meehl, G A and Arblaster, Julie M.: Simulation of Indian Summer Monsoon Rainfall and Its Intra-Seasonal Variability Regional Environmental Change 1(3 & 4) (2000), pp.163-179 Copyright © 2005 Taylor & Francis Group plc, London, UK 196 IMPLICATIONS FOR INDIA’S WATER RESOURCES Lal, M., Nozawa, T., Emori, S., Harasawa, H., Takahashi, K., Kimoto, M., Abe-Ouchi, A., Nakajima, T., Takemura, T and Numaguti, A.: Future Climate Change: Implications for Indian Summer Monsoon and its Variability, Current Science (2001) (Communicated) Lander, M.: An Exploratory Analysis of the Relationship Between Tropical Storm Formation in the Western North Pacific and ENSO Mon Wea Rev 122 (1994), pp.636-651 Meehl, G A and Washington, W M.: El Niño-Like Climate Change in a Model with Increased Atmospheric CO2 Concentrations Nature 382 (1996), pp.56-60 Mitchell, J F B., Johns, T C., Gregory, J M and Tett, S F B.: Climate Response to Increasing Levels of Greenhouse Gases and Sulphate Aerosols Nature 376 (1995), pp.501-504 Nakicenovic, N., Alcamo, J., Davis, G., de Vries, B., Fenhann, J., Gaffin, S., Gregory, K., Grubler, A., Jung, T Y., Kram, T., La Rovere, E L., Michaelis, L., Mori, S., Morita, T., Pepper, W., Pitcher, H., Price, L., Raihi, K., Roehrl, A., Rogner, H H., Sankovski, A., Schlesinger, M., Shukla, P., Smith, S., Swart, R., van Rooijen, S., Victor, N and Dadi, Z.: Emissions Scenarios, A Special Report of Working Group III of the Intergovernmental Panel on Climate Change, Cambridge University Press, Cambridge, 2000, p.599 Nakicenovic, N., Victor, N and Morita, T.: Emissions Scenarios Database and Review of Scenarios Mitigations and Adaptation Strategies for Global Change (1998), pp.95-120 Pant, G B and Kumar, K R.: Climates of South Asia, John Wiley & Sons Ltd., West Sussex, U.K., 1997, p.320 Pender, M.: Recent Retreat of the Terminus of Rika Samba Glacier, Hidden Valley, Nepal In C P Wake (ed.), Himalayan Climate Expedition - Final Report, Glacier Research Group, University of New Hampshire, 1995, pp.32-39 Ramakrishnan, S.: Ground Water, Published by S Ramakrishnan, Chennai, 1998, p.471 Royer, J F., Chauvin, F., Timbal, B., Araspin, P and Grimal, D.: A GCM Study of the Impact of Greenhouse Gas Increase on the Frequency of Occurrence of Tropical Cyclones Climatic Change 38 (1998), pp.307-343 Saunders, M A and Harris, A R.: Statistical Evidence Links Exceptional 1995 Atlantic Hurricane Season to Record Sea Warming, Gephys Res Lett 24 (1997), pp.1255-1258 Singh, T.: Drought Disaster and Agricultural Development in India, Peoples Publishing House, New Delhi, 1995 Suresh, V.: Sustainable Development of Water Resources in Urban Areas, Proc 10th National Symposium on Hydrology, July 18-19, CSMRS, New Delhi, 2000 Timmermann, A., Oberhuber, J., Bacher, A., Esch, M., Latif, M and Roeckner, E.: Increased El Niño Frequency in a Climate Model Forced by Future Greenhouse Warming Nature 398 (1999), pp.694-696 Webster, P J., Magana, B O., Palmer, T N., Shukla, J., Thomas, R A., Yanagi, M and Yasunari, T.: Monsoons: Processes, Predictability and the Prospects for Predication Journal of Geophysical Research 103(C7) (1998), pp.14451-14510 Yamada, T., Fushimi, H., Aryal, R., Kadota, T., Fujita, K., Seko, K and Yasunari, T.: Report of Avalanches Accident at Pangka, Khumbu Region, Nepal in 1995 Japanese Soc of Snow and Ice 58(2) (1996), pp.145-155 Zerah, M H.: Water’s Unreliable Supply in Delhi, Manohar Publishers and Distributors, New Delhi, 2000, p.168 Copyright © 2005 Taylor & Francis Group plc, London, UK ... 44 40 17 12 37 32 2425 20 15 14 21 1511 15 -2 0 -1 3 -1 9-1 6 -1 2 -6 -9 Punjab Haryana, Chandigarh & Delhi -3 -1 0 -1 1 -1 2 -2 5 -2 5 -4 0 -9 -1 5 Kerala East Madhya Pradesh -6 -1 8 -1 2 -1 5 -2 1 -2 8 North... exchange of information on the state-of-the-art thinking about climate change and impacts on water resources The timely flows of information among the climate change scientists and the water- management... level leads to intrusion of saline water far into the land mass through the rivers draining into the sea and it also increases ground water contamination by making water saline Saline water Copyright