21 Water availability, scarcity and climate change

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Objectives

 

Water Availability and Scarcity, Water Stress, Water Pollution, Water Quality Status, Climate Change and Its Impact

 

Keywords

 

Water,Availability, Stressed, Pollution,Quality,Climate Change,Impacts,India

 

INTRODUCTION

 

The water situation in India seems to be going from bad to worse. Not only is there a growing scarcity of water in the country, the agriculturally important states like Punjab, Haryana, Tamil Nadu and Rajasthan are facing a steady fall in their ground water level and deterioration of water quality as well. While in the per capita availability of utilizable water in India in 1951 was 3,450 cubic meter in 1999 it came down to 1,250 cubic meters. This according to the Ministry of Water Resources, is expected to decrease to 662 cubic meter per person in 2050. In 2015, only 78 percent of the rural and 85 percent of the urban Indians had access to potable water. Rapid depletion of the ground water level and quality is a cause of great concern for India as its agriculture depends overwhelmingly on this source of water. One estimate has it that groundwater sources account for as much as 70 to 80 percent of the value of agricultural produce attributable to irrigation. Rain-fed farming also has a distinct place in the country’s agriculture, occupying 67 percent of the cultivated area, contributing 44 percent of the food grains and supporting 40 percent population. In fact even after realizing the complete area will continue to depend on the rainfall. So there is an urgent need to emphasis on water situation, its scarcity and quality deterioration over time, so that timely management and planning can be done.

 

WATER AVAILABILITY

 

The National Commission on Integrated Water Resources Development Plan estimates that total water resource potential of country or natural water availability as 1,953 billion cubic metres (BCM) (432.94 BCM groundwater and 1,520 BCM surface water). Due to variability in time and space and topographical challenges, the usable surface water resources are 690 BCM; total replenishable groundwater is estimated at 432,94 and us BCM able groundwater resources are estimated at 396 BCM; total water resources are 1,086 BCM, although the estimated does not include water resources of areas of north Ladakh not draining into Indus and the Andaman and Nicobar Island and Lakshadweep (Table 1). The Central Water Commission estimates water resources as 1,123 BCM (690 BCM surface water and 433 BCM groundwater).

 

Table 1: Water Resources of India

Source: Central Water Commission, 2011

 

India receives an average annual rainfall equivalent of about 4,000 billion cubic metres (BCM). This source of water is unevenly distributed both spatially as well as temporally. Most rain falls in the monsoon season (June-September), necessitating the creation of large storages for maximum utilization of the surface run-off. Within any given year, it is possible to have both situations of drought and of floods in the same region. Regional varieties are also extreme, ranging from a low value of 100 mm in Western Rajasthan to over 11,000 mm in Meghalaya in North-Eastern India.

 

Surface water in India consists of Twenty-two major river basins. National level statistics for water availability mask huge disparities from basin-to-basin and region to region. Spatially, the utilizable resource availability in the country varies from 18,417 cubic meters in the Brahmaputra valley to as low as 180 cubic metres in the Sabarmati basin. Rajasthan, for instance, with 8 per cent of the country’s population has only 1 per cent of the country’s water resources while Bihar with 10 per cent of population has just 5 per cent of the water resources. Thus, while India is considered rich in terms of annual rainfall and total water resources, its uneven geographical distribution causes severe regional and temporal shortages.

 

Figure 1: River Basin Map of India

 

Source: Central Water Commission

 

The annual estimate of surface water in India is 1,86,900 crore cubic meter. Most of the surface water in India comes from 14 major river systems- The Ganga, Brahmputra, Sindhu, Godavari, Krishna, Brahmani, Mahanadi, Mahi, Narmada, Tapi, Sabarmati, Kaveri and Peiyar. These river systems constitute 83 percent of the drainage basin, account for 80 percent of the surface flow, and house 80 percent of the total population of the country. Apart from them, there are 44 medium and 55 minor river systems-most of these are fast flowing, rain-fed and originate in the Ghats (Figure 1).

 

Abundant ground water resources are found only in the northers and coastal plains; elsewhere they are inadequate. About 300 lakh hectare meter water is available in India at present. Unfortunately, every year quality of underground water is reducing. Although about 270 lakh hectare meter water is added to underground water every year though infiltration of rain water and seepage from canals, but so much excess water is being used in agriculture and industry that the water level is going lower and lower day by day.

 

R.L. Singh, in his book India: A Regional Geography has divided groundwater areas of India into eight regions as under:

  1. Precambrian Crystakkine Rocky Region: Almost half of the area of the country is included in this region, which extends to Tamil Nadu, Karnataka, Andhra Pradesh, Dandakaranya, Bundelkhand etc.
  2. Precambrian Sedimentary Rocky Region: This area extends to Cuddappa and Vindhyan Basin.
  3. Gondwana Sedimentary Rocky Region: Sufficient water is found in this region that is in the Barakar and Godavari basin area, which have sand rocks.
  4. Deccan Trap Region: In this region there is a 1200 meter thick impermeable basalt strip where there is shortage of groundwater.
  5. Cenuzoic Sedimentary Rocky Region: This is a tertiary carpet having sufficient groundwater, which is located in the coastal parts of Tamil Nadu, Andhra Pradesh, Kerala and Gujarat.
  6. Cenuzoic Fault Basin Region: Situated on the fault basins of Narmada, Tapti and Purna rivers, sufficient groundwater from Kamp Jamav is available here.
  7. Ganga Brahmputra Alluvial Region: In this region, there is enourmous water at the upper level.

 

Himalayan Region: This is not important from the point of view of groundwater, the main reason being its compact composition.

 

In eastern Uttar Pradesh, Bihar, West Bengal and Orissa there is thick layer of marshy soil spread over the ground, hence they are most suitable for under groundwater development because of lesser depth. The level of groundwater development is 6 percent in Orissa, 19 percent in Bihar, 24 percent in West Bengal and 34 percent in Western Uttar Pradesh. Since, the depth of groundwater in these states varies from 5 to 10 meters, hence use of groundwater is comparatively easier here.

 

In addition to rivers, a large number of reservoirs, lakes, ponds, wet lands, mangroves etc. dot the entire country. These water bodies are the “lungs” of the country that regulate both the quality and quantity of water in addition to supporting the various life forms.

 

Due to the increasing population in the country, the national per capita annual availability of water has reduced from 1,816 cubic metre in 2001 to 1,544 cubic metre in 2011. This is a reduction of 15%. Figure 2 shows the probable trends in per capita water availability for hundred years from 1947 to 2047. The problem of water shortage is further complicated when we look at the areal distribution of water resources with reference to population.

 

Figure 2: Declining Availability of Water in India

 

Inspite a large network of rivers and other water bodies in our country, we face the problem of availability of drinking water and water scarcity. India is facing an increasingly urgent situation; as its finite and fragile water resources are stressed and depleting while different sectoral demands are growing rapidly. This situation has developed incrementally, but is nevertheless dramatic.

 

WATER SCARCITY

 

There are several ways of defining water scarcity. Generally, Water scarcity is the lack of sufficient available water resources to meet water needs within a region.

 

Water scarcity involves water shortage, water stress or deficits, and water crisis. The relatively new concept of water stress is difficulty in obtaining sources of fresh water for use during a period of time; it may result in further depletion and deterioration of available water resources. Water shortages may be caused by climate change, such as altered weather-patterns (including droughts or floods), increased pollution, and increased human demand and overuse of water. The term water crisis labels a situation where the available potable, unpolluted water within a region is less than that region’s demand.

 

Malin Falkenmark developed the concepts of water stress and water scarcity based on an index of per capita freshwater needs. She estimated a minimum need of 100 liters per day per person for household use and from 5 to 20 times as much for agricultural and industrial uses. The concept have been widely accepted and used by hydrologists, the World Bank, and other organizations. For example, Population Action International (PAI) has replied on them to make projections of per capita water availability and to forecast water shortage in 2025 and 2050.

 

India, which has 16 percent of the world’s population, 2.0 percent of the world’s land area and 4 percent of the world’s water resources is already heading towards a state of water crisis. A late monsoon in 2002 resulted drought in 13 of the 29 states in the country. But drought apart, otherwise too there is a huge gap between the quantity of water that is made available to us by Mother Nature and the quantity that we are utilizing.

 

Box 1: Water Needs

 

Some 200 million do not have access to safe and clean water. An estimated 90 percent of the country’s water sources are polluted with untreated industrial and domestic waste, pesticides and fertilizers run-off from fields. According to a publication of the Rajiv Gandhi Drinking Water Mission-‘Introduction to Rural Water Supply and Sanitation Programme in India, Published in 2011-about 1.5 million children under 5 die each year from water borne diseases. The country also loses over 200 million workdays annually due to these diseases.

 

Further, India is the second largest consumer of water in the world, after China. India’s water consumption is approximately 720.1 percent of the world consumption. Per capita water consumption in India, at 297.7 cubic meter, is more than the world average per capita consumption of 287.3 cubic meter.

 

INDIA TO BECOME WATER STRESSED BY 2050

 

India’s total annual renewable fresh water resources are estimated at 2,086 BCM. However, the annual average water availability (AWA) in terms of utilizable water resources within the limitations of physiographic conditions, socio-political environment, legal and constitutional constraints and the technology of development as available is estimated at 1086 BCM, comprising 690 BCM of surface water and 395.6 BCM of ground water. Water scarcity has been defined according to “supply-side” approach in the pioneering study by Falkenmark Lundqvist and Widstrand. For this purpose, ranking has been done according to per capita amount of “Annual Water Resources” (AWR). They define 1,700 cubic meter per capita per year as the level of water supply above which shortage will be local and rare. Below 1,000 cubic meter per capita per year water supply will hamper health, economic development and human well-being. At less than 500 cubic meter per capita per year water availability is a primary constraint to life.

 

India will be on the list of water-stressed countries by the year 2025 when nearly half the world population will experience water shortage and also come into the categories of high and extremely high water stressed condition (Figure 3). Today, nearly 1.2 billion people do not have access to safe drinking water. The stress on water resources is the result of a multitude of factors such as rapidly rising population and changing lifestyles that have increased the need for freshwater and intense competition among agriculture, industry and the domestic sector that is pushing the groundwater table deeper.

 

Figure 3: Water Stress Situation in India

Source: World Resource Institute (www.indiawatertool.in), 2015

 

Nearly 40 percent of India’s urban population, which is below the poverty line, has no access to water. The scenario in rural India is also worse. In 1985, there were 750 villages without water resources, with the number increasing to 65,000 villages in 1996. But these figures of fast depleting water table have another story to tell. It has changed the lifestyle of the villages. Researchers at The Tata Energy Resources Institute (TERI), with funding from the United Nations Population Fund (UNPF), tried to understand the linkages between population and water by carrying out a survey at the national and village levels to ascertain the impact of population growth on water resources and that of availability of water and water quality on the life of the people, particularly women and children.

 

Table 2: Categorization of Block/Mandals/ Taluka in India for Water Critical Condition

 

Source: Ministry of Water Resource, 2011

 

The study conducted by TERI, in 350 households in 20 villages in the districts of Thiruvananthapuram, Solan, Raichur and Bikaner threw up some interesting facts. In all the villages surveyed, water scarcity was a common problem but the perceptions were different. For some areas in Bikaner and Raichur, water shortage meant shortage even for drinking and in Solan, the problem connoted shortage for irrigation purposes. For instance, of the villages surveyed in Bikaner, there were cases of households with 5-6 members managing with just 10 litres of water a day while in the villages of Solan, drinking water did not appear to be a problem, but water for irrigation was an immediate requirement. On the other hand, the villages surveyed in Thiruvananthapuram did not face water scarcity except in summer months when few households in coastal villages experienced the problem of salt-water mixing with the water in wells. In all the villages surveyed, it appeared that there was considerable effort for collecting water for drinking and other household uses. The stress varied from region to region depending on water resources, waiting time and number of trips required.

 

The Central Ground Water Board (CGWB) has recorded a yearly drop of 2.5-3 meter in ground water levels of Ahmedabad urban areas where the rate of exploitation of city’s aquifers is 1.23 percent. The worst affected are the states of Rajasthan, Gujarat, Parts of Andhra Pradesh and Western Madhya Pradesh where water was abundantly available 10-15 years ago. The groundwater table in these areas has fallen below 300 meters. Now, and drought has become a yearly phenomenon. As per estimates of 2010, 839 blocks were reported overexploited while 226 blocks were reported to be critical in terms of ground water development. The proportion of overexploited blocks was reported high in Punjab, Delhi, Rajasthan, Tamil Nadu, Karnataka, Haryana and Andhra Pradesh (Figure 4).

 

Figure 4: Groundwater Level Deterioration at District Level in Indian States

 

Source: World Resource Institute (www.indiawatertool.in), 2015

 

There has been a gradual increase in dark blocks in India during 1984-85 to 2015. The highest increase has been reported in the states of Andhra Pradesh, Karnataka, Madhya Pradesh, Rajasthan and Tamil Nadu (Figure 4). Critical four Indian States viz. Punjab, Rajasthan, Haryana and Delhi are depleting at least 30 percent more of their groundwater resources than previously estimated by government. The scientists report that these states have depleted on an average 17.7 BCM of water annually between August, 2002 and October, 2015.

 

Table 3: Over Exploited and Dark Blocks in Some States

 

Source: Central Water Commission, 2015

This is more than the government’s estimates of 13.2 BCM in the same period. The groundwater depletion in the region was equivalent to a net, irreplaceable loss of 109 BCM, nearly 20 percent of annual water consumption of 634 BCM. Besides this, megacities receive 150 lpcd, town with population more than one lakh (34) where sewerage system exists 135 lpcd, and other town (586) get 70 lpcd water supply. Table 4: Demand and Supply Position of Water in Metro Cities

 

Source: NIUA (2001)

 

A PANOROMIC VIEW OF WATER SITUATION IN A FEW STATES Rajasthan: The State of Rajasthan is often affected by droughts during summers. The summer of 2000 had been the worst ever affecting 26 out of 32 districts. This grim picture was worsened by the fact that out of 34,609 villages, 23,500 were reeling under drought and at least 35 million people and 37.5 million cattle were affected.

 

Marwar region’s seven districts account for 12.2 million population and 1,35,519 sq. km geographical area. As per the latest census the growth rate in population here ranged from 47.45 per cent in Jaisalmer district to 22.39 per cent in Pali district. The most populated of all deserts in the world the density in the Thar varied from 13 persons per sq. km. in Jaisalmer to 166 persons per sq. km. in Sirohi. The ground water availability in the region is poor with only 56.83 per cent of the total area holding any potential. Out of the potential areas too, in 45.21 per cent the ground water sources have been over-exploited, in 18.60 per cent it is critical and in 2 per cent it is semi critical. Only 34.20 per cent of the available landmass is under safe category.

 

     Kutch Region of Gujarat: The north-western region of Gujarat is well known as water scarce and drought prone. Owing to its semi-arid character, scarcity of water is however not a recent phenomenon in Kutch. What a recent is the problem of drinking water despite having one of the largest piped water supply network in Gujarat, covering 92 percent village in Kutch. But despite huge investment in piped water supply, this region of Gujarat reels under a severe drinking water crisis throughout the year. More than 20 percent villages remain under tanker water supply. The annual expenditure on tanker water supply exceeds Rs. 20 million besides large capital and operational expenses of the public water supply schemes. In this region, there is failure of modern and traditional technologies and wells and bores are drying up rapidly. Even tube-wells are fast turning saline and drinking water quality is deteriorating. This is happening not in one village or in a taluka, but all over Kutch. More importantly, the technologies for withdrawing water catalyzed a much faster depletion of ground water. The over-extraction of ground water has led to a rapid depletion of water table and sharp deterioration in the quality of water across the districts.

 

Punjab: The emerging water crisis pose a grave threat of Punjab state. The estimates of scientist reveal that good quality water is available to the extent of 3.12 million hectare meters, whereas the normal requirement amounts to 4.90 million hectare meters. The net deficit comes out to 1.78 million hectare meters. The possible addition to surplus of water after treating the marginally fit water available in different parts of state is estimated to be 0.24 million hectare meters. The amount of deficit is so substantial that unless a very serious view is taken of the matter and immediate corrective policy measures adopted, the state is heading towards a critical water famine situation. The fast changing cropping patterns have precipitated the water crisis since ushering of the green revolution in the mid-60s. Consequently, the water table has been going down for the past four decades. A recent study by Dr. Joginder Rana, Head, Department of Economics and Sociology, Punjab Agricultural University, Ludhiyana indicates that the situation is pretty grim in the central or sweet water region of the state and also in the sub-mountainous or the Kandi zone, whereas in the south-western zone the rising water table has posed a different set of problem like salinity and water-logging. The water table is falling at an average rate of 0.23 meter per year, during the past 15 years. The water table which was 5 to 6 meters in 1981, has now shown a fall of 24cm to 25cm per annum. In the south-western zone, which comprises almost one-fourth of the state’s cultivated area, the groundwater is brackish and unfit for crops and humans.

 

Delhi: Inadequate and inferior quality water supply in Delhi state has become a matter of serious concern. It has been accepted by the Mayor of Delhi that the civil authorities have been able to provide potable water to hardly 40 percent of Delhiites. Apart from the 1600 unauthorized colonies and 1100 slums, a large chunk of the city’s rural belt which fall in the water deficient zone is facing acute water scarcity. Delhi’s peak summer demand is estimated to be about 850 million gallon daily (mgd.), but Delhi Jal Board manage to provide just over 650 mgd. Tata Energy Research Institute (TERI) in their recent study claims that the water table in most parts of the metropolis is falling rapidly and in many places in South Delhi is almost bone dry. In Mehrauli zone, the groundwater may get exhausted in the next 10 years. A survey of the trend in water level between 1960-2010 show a constant decline, which declined by two to six meters in most parts of the Delhi alluvial areas.

 

WATER SCARCITY STATUS IN RIVER BASINS

 

It will be pertinent to describe the two important river basins in the Indian subcontinent which have their ramifications on relations with the neighboring countries viz. Pakistan. Nepal and Bangladesh. These are (i) Indus basin and (ii) Ganga basin.

 

Indus Basin: The Indus basin begins in Tibet and flows through India and Pakistan, about 60 million people reside in the basin area, which covers the northern and northwestern states. The fight for water has been ongoing in the Indus basin, with water table dropping because of groundwater over-pumping and basins running dry during the summer season. Water scarcity in this basin is an international issue; after the independence, India and Pakistan nearly went to war over this basin. However, a water treaty was established in 1960 and that has proved resilient.

 

Ganga Basin: The Ganga, the subcontinent’s largest and most important river, rises in Nepal and flows 1,400 miles through three densely populated Indian States of Uttar Pradesh, Bihar, and West Bengal-before entering Bangladesh and flowing into the Bay of Bengal. The Ganga River basin within India encompasses nearly 26 percent of the total geographical area of the country, and is inhabited by 323 million people. Physical cropland in the Indian part of the basin is estimated to be 58 million hectares or 30 per cent of the total crop land of the country, of which 20 percent is irrigated. Even though the Ganga does not seem water-scarce based on total annual flows, it often experiences severe water stress from January to April, and floods during other months.

 

There was perpetual serious dispute over sharing of Ganga water, with the then East Pakistan. The conflict persisted even after the creation of Bangladesh. However, a new chapter in the Indo-Bangladesh relations opened up with the signing of the Indo-Bangladesh Treaty by the Prime Ministers of India and Bangladesh on l2th December, 1996 on sharing of Ganga Waters for a period of thirty years.

 

Other River Basins: Apart from these two important river basins, there are other river basins and a number of stales have become embroiled in disputes over water rights and over darns that might provide more water for one state but at the expense of another. “Water disputes, if not attended to, will become a major headache for the stability of Indian Society”, says Mohan Katarki, a Lawyer representing Karnataka state in a water dispute with Andhra Pradesh. These two states are arguing the court over the height of a dam on Krishna River, which could affect the amount of water available for use by both states. Similarly conflict over sharing Cauvery waters among the riparian states of Kerala. Karnataka, Tamil Nadu and Pondicherry has taken a serious dimension.

 

Thus, water is becoming a contentious issue in India, as the dispute over the sharing of Cauvery waters has clearly shown. This has sharply brought home the urgency of cooperative and integrated management of water resources.

 

WATER QUALITY

 

Importance and scarcity of water is well known, but even 10 percent part of fresh water is not free from water pollution. Rivers, lakes, tanks and underground water are continuously become polluted and deteriorating its water quality day by day.

 

Water quality is a complex subject, which involves physical, chemical, hydrological and biological characteristics of water and their complex and delicate relations. From the user’s point of view, the term “water quality” is defined as “those physical, chemical or biological characteristics of water by which the user evaluates the acceptability of water”. For example for drinking water should be pure, wholesome, and potable. Similarly, for irrigation dissolved solids and toxicants are important, for outdoor bathing pathogens are important and water quality is controlled accordingly.

 

Table 5: Impacts of Different Pollutants on Water Quality

 

Source: Created by Author

 

WATER QUALITY STANDARDS

 

The Central pollution Control Board (CPCB) is the regulatory authority of water quality in India. The various physio-chemical and biological parameter of quality of different classes of water are already discussed above. It becomes apparent that most of the drinking water of rivers in India at various locations are generally not suitable for direct use, as their BOD value and coliform counts are higher than the prescribed limits. A concept of “designated best use” (DBU) was developed. According to this concept, out of several uses a water body is put to, the use which demands highest quality of water is termed as “designated best use”, and accordingly the water body is designated. Primary water quality criteria for different uses have been identified.

 

Table 6: Water Quality Standards for Different Users Developed by CPCB

 

    WATER QUALITY STATUS IN INDIA

 

The water quality monitoring results obtained during 1995 to 2015 indicate that the organic and bacterial contamination are continued to be critical in water bodies. This is mainly due to discharge of domestic wastewater mostly in untreated form from the urban centers of the country. The municipal corporations at large are not able to treat increasing load of municipal sewage flowing into water bodies without treatment. Secondly the receiving water bodies also do not have adequate water for dilution. Therefore, the oxygen demand and bacterial pollution is increasing day by day.

 

It becomes evident from figure below that overall fresh water in India is slightly alkaline with a lot of HCO3 and CA2. About 2.17 lakh of habitation in India were reported affected with quality of water. Most of such habitation have been reported in the state of West Bengal, Rajasthan, Orissa, Karnataka and Assam. The fluoride affected habitations were reported mainly in the states of Rajasthan, Madhya Pradesh, Karnataka, Gujarat and Andhra Pradesh, while arsenic affected habitation were reported mainly in West Bengal (Figure 5).

 

About 66.62 million rural population of the country is forced to consume fluoride contaminated water. This constitute about 7 percent of the total rural population. The proportion consuming fluoride contaminated water has been reported high in the state of Rajasthan (20.60 percent) followed by Andhra Pradesh (18.10 percent), Karnataka (13.40 percent) and Tamil Nadu (12.40 percent).

 

Figure 5: Water Quality Status in India

Source: Central Pollution Control Board, 2015

 

Several regions of the urban and coastal belts in India have been declared hot spot due to transport of contaminated surface waters from urban areas to coastal areas. Similarly all regions of the country that do not meet even the water quality criteria class “E” can also be considered as potential hot spot. Areas where water availability is fairly very low due to poor rainfall, such as Gujarat, Rajasthan and Tamil Nadu may also be considered as potential hot spot. Regions with specific problems of fluoride and arsenic are also hot spots. These include Ajmer in Rajasthan, Ananthpur in Andhra Pradesh and seven districts in West Bengal and Bangladesh. Even in Delhi, highly acidic industrial effluents from metal based small scale unit’s discharge into small water bodies that in turn drain into the river Yamuna. Hence, all such water bodies are potential hot spot in India.

 

Table 7: Potential Hot Spot in Selected Locations in India

 

Source: Pangare et. al., 2006

 

     Most of the rivers at a few selective points such as Rishikesh for Ganga, Ranganthintu for the Cauvery and Mandhavi in Goa are suitable for bathing. Water for number of water bodies such as the Sukhna Lake in Chandigarh, Ramgarh Lake in Udaipur, Asthmudi Lake in Kerala and Narmada River in Bharuch is suitable for drinking water after conventional treatment and disinfection. Some lakes in Pondicherry and Ganga at Varanasi belongs to class E. there are still some water bodies at various places throughout the country that are even below class E, meaning totally unfit for any use. Such water bodies include the river Sabarmathi in Ahmedabad, Elephanta Island in Maharashtra and Asthanmudi backwater in Quilon, Kerala.

 

 

Table 8: Average Chemical Composition of Major Rivers in India

 

Source: Central Pollution Control Board, 2015

 

CLIMATE CHANGE AND WATER RESOURCE IN INDIA

 

Climate change is a “change of climate which is attributed directly or indirectly to human activity that alters the composition of the global atmosphere and which is in addition to natural climate variability observed over comparable time periods”.

 

Figure 6: Climate Change and Water Resource Stress in World

Source: Intergovernmental Panel on Climate Change (IPCC)

 

The World Bank Report (2013), “Turn Down the Heat: Why A 4 Degree Centigrade Warmer World Must be Avoided”, recognize the that the impacts of climate change would differently distributed across the world and will be felt disproportionally in the tropics and among the poor because the geographic and socio-economic conditions produce certain vulnerabilities in different regions. South Asia, according to the report, is particularly vulnerable as the region host a fourth of the world’s population. That number now stands at 1.7 billion, but it will rise to 2.3 billion in 2050. With widespread poverty, the impacts of climate change could severely affects the economy, water resource, agriculture, and population movement due to intense heat, flooding or diseases (Figure).

 

Climate Change in India

 

India is a vast country with a rural population of 700 million people subsisting on climate-sensitive sectors of agriculture, forest and fisheries, with the support of natural resources like water, biodiversity, mangroves, coastal areas, and grassland for livelihood. The timely arrival of the summer monsoon is critical for the rural economy of India as well as the region. The ability of dry-land farmers, forest dwellers, fisherman and nomadic tribes to adapt to climate change is poor. Decrease in the availability of seasonal water, together with population increases, may have severe effects on water and food security.

 

The IPCC (Intergovernmental Panel on Climate Change) report predicts that there will be a 2.7-4.3Oc increase in temperature in India by 2080. The panel also mentions an increase in rainfall over the subcontinent by 6-8 percent and a rise in sea level by 88cm by 2100. The most recent modelling done for India is based on the regional climate modelling (RCM) system, known as PRECIS, developed by the Hadley Centre, using IPCC scenarios. The model depicts the following facts given in Box 2.

 

Box 2: Climate Change under IPCC Scenario

 

An annual mean surface temperature rise by the end of this century, ranging from 3OC to 5OC and 2.5OC to 4OC (under B2 scenario), with the warming more pronounced in the northern parts of India.

 

A 20 percent rise in all-India summer monsoon rainfall and a further rise in rainfall in projected over all states except Punjab, Rajasthan and Tamil Nadu, which shows a slight decrease.

 

Extreme rise in maximum and minimum temperatures and similarly extreme precipitation are also projected, particularly over the west coast of India and West Central India.

 

Climate Change and Water Resources

 

Climate change is projected to have vast adverse effects on India’s water resources and further complicate and impact intensity, spatial and temporal variability of rainfall, evaporation rates, and temperatures in different agro-climatic zones and river basins. The impacts of climate change vulnerability would be varied in different regions, states and districts of India and will be felt in both surface water and ground water resources (Figure 7).

 

Figure 7: District level Vulnerability to Climate Change in India for Water Resource

 

Source: Ministry of Water Resource, 2011

 

Estimates of the rise in temperatures in India are based on different models and they come with considerable uncertainty; however, there is high confidence that the temperature increases will be above any levels experienced in the last 100 years. For example, Kumar et al. (2010) estimate that a local warming of 2°C is expected by midcentury, and 3-5°C above the 1961-1990 mean is projected by the end of the twenty-first century (World Bank Report, 2013). This definitely means a fundamental shift in the hydrological regimes of not only India but the South Asia in its entirety. Geographically, the mountains of the Himalayas and the Hindu Kush confine the monsoons to the region and influence the water geography of the region in a fundamental manner.

 

Climate Change and Its Impacts on Water Resource

 

1. Impacts on Hydrology and River Flows: The Ganga, Brahmaputra, and the Indus rivers are fed by the Tibetan Plateau and adjacent mountain ranges (Uprety and Salman, 2011). Over 50 percent of the world’s population lives downstream of the Great Himalayan region where increasing occurrence of low snow years and a shift to an extreme winter/spring runoff and extremely slow summer runoff would increase flood risks during winter/spring and decrease availability of freshwater during summer (Giorgi et al., 2011). There exists an overall risk to the flow of these rivers. For the 2045-2065 period, with a global mean warming of 2.3°C relative to preindustrial levels, very substantial reduction in the flow of the Indus and Brahmaputra has been predicted in late spring and summer. The projected increase of rainfall upstream cannot compensate for these reductions because they follow the spring period of increased flow due to melting glaciers. The Ganges, due to high annual downstream precipitation during the monsoon season, is less dependent on meltwater (Immerzeel et al., 2010). More recent research demonstrates a rapid increase in the frequency of low snow years in the coming few decades with shifts toward high runoff and spring flows and very low summer flows well before a 2°C warming. Thus precipitation change, loss of glacial ice, and a changing snowmelt regime could lead to substantial changes in the downstream flow, Hydrological stress in snow-dependent regions is likely to intensify beginning in near-term decades when global warming is likely to remain within 2°C of the preindustrial baseline.

Table 9: Region-wise Concerns due to Climate Change in India

 

Source: Central Water Commission, 2011

 

The total runoffs for upper parts of Mahanadi, Brahmani, lower parts of Gariga, Subarrtarekha, Godavari, Pennar, and Cauvery basins will not increase even under conditions of increased precipitation by the 2080s. Projected runoffs for various basins except Narmada and Tapi show decline as many factors contribute to the runoff in the river. The increase in runoff may result from the intensity of rainfall due to climate change. The Sabarrnati and Luni river basins may have decreased precipitation and also runoff declines of two-thirds (MOEF, 2009: 82-83), It seems that unless remediation steps succeed, the water resources in rivet basins are likely to decline. The reductions in precipitation will lead to reduction in water yield. This situation refers to the period of midcentury (2040-2060) scenario where warming will be around 2-3°C, but the situation under the end-of-century (EC, 2080-2099) scenario improves where all rivers exhibit increase in precipitation, There is also a predicted increase in the water yield of the rivers under end-of-century scenario but for the majority of the river systems, evapotranspiration also increases by more than 40 percent. The only two river basins, which show some decrease in evapotranspiration under the end-of-century scenario, are the Cauvery and Krishna. The major reason for evapotranspiration is increase in temperature and precipitation.

 

2. Impacts on Water Security: Although it is difficult to predict the exact nature of impacts on climate change, and it may take decades to fully understand the impacts of temperature rise and subsequent glacial melting and sea-level rise, all this uncertainty in such a fluid situation is even more alarming. One study, which applies a multifactorial water security index, finds that on a scale of 0 (no apparent threats) to 1 (extremely threatened), Central India stands between 0.8 and 1, and along the mountain ranges of the Western Ghats of South India, in the northeastern states of India, the threat level is high to very high (0.6-0.8) (Vorosmarty et al., 2010). Using another benchmark based on the Falkenmark index, a country is considered water stressed if less than 1,700 m3 river basin runoff per capita is available, and the entirety of South Asia falls under that category.

 

ESCAP (2011) identifies India, Bangladesh, Pakistan, Maldives, and Nepal as water hot spots in the Asia Pacific region. The six main countries of this region are already overrepresented on Maplecroft’s Natural Disasters Risk Index (Pakistan 4th, India 11th, Afghanistan 15th, and China 12th). The economic impacts of climate change will be most keenly felt by Bangladesh (1st and most at risk), India (20th), and Pakistan (24th) (Maplecroft 2013).

 

Climate change envisions changes in water availability, leading to migration, displacement of people, livelihood losses in agriculture and fishing, disease, and conflict that could have spillover affects across boundaries. Projections demonstrate that climate change will aggravate the pressure on water resources due to an already increasing population and its water demand.

 

3. Impacts on Water availability: One of the key fundamentals of water security is the reliable availability of and access to water resources to meet people’s basic needs and support their livelihoods and quality of life. Studies estimate that gross per capita availability including surface and replenish able groundwater is supposed to decline from 1,829 m3 to 1,140 m3 in 2050 due to population growth alone (Gupta and Deshpande, 2004). Without taking other factors into account, India will be water scarce in 2050 with population alone (Figure 3). By altering hydrological patterns and freshwater systems, climate change poses an additional risk to water security (ESCAP, 2011; Green et al., 2011), mainly to the agricultural sector, which is the largest consumer of blue water in India. For example, in the case of the Ganges alone, where projected runoff can be expected to increase by 20 percent without climate change factored in will instead increase by as much as 50 percent with 2.7-4°C warming. At 4°C warming, annual mean runoff is projected to offset the demand for water due to population growth, but at 2°C warming, the total annual mean runoff is not sufficiently large to mitigate this demand. These increases will be seasonal, implying severe flooding in high-flow seasons and aggravated water stress in dry seasons if adequate storage capacities are not built to counter these impacts (Fung et al., 2011; World Bank, 2013). A decrease in the flow of the Mahariadi will account for decreases in the Hirakud reservoir, and water management policies will need to be adjusted accordingly. The likelihood of water scarcity driven by climate change alone has been estimated to be as high as 30-50 percent in India and as high as >90 percent for Pakistan.

 

Groundwater in India is at a critical stage and represents a major challenge to water availability (Figure 4). About 15 percent of India’s groundwater tables are exploited, and its utilization is intensifying with an increasing rate of 2.5-4 percent (MOEF, 2012), with no enforceable groundwater laws yet across the country, reductions in groundwater resources and depletion of water tables are a logical consequence. This in fact will cause a decline in agricultural production and availability of drinking water even without climatic factors. However, climate change is expected to further aggravate the situation. Availability of groundwater resources is imperative to mitigate droughts and ensure agricultural growth since India uses 60 percent of its groundwater for agriculture and 50-80 percent for domestic water use. Groundwater is replenished through monsoon rainfall, and the variability of the rains will have an effect on the availability of water resources. Rising sea levels with intruding saltwater will also threaten water availability. Thus, the shortfall of surface water and groundwater availability and access under climate change exposes the population to severe risks including food scarcity and threats to livelihood security.

 

4. Impacts on Water quality: In addition to water availability and access, clean, potable water is also an important element of water security. Using water quality responses to six hypothetical climate change scenarios simulated by the water quality model, QUAL2K, Rehana and Majumdar (2011) concluded that each scenario would impair water quality. Their results showed a significant decrease in DO (Dissolved Oxygen) levels due to the impact of climate change on temperature and flows, even when the discharges were at safe, permissible levels set by pollution control agencies IPCAs.

 

5. Transboundary and Interstate Challenges: Since the major river basins in the northern region of the Indian subcontinent extend into the borders of other states, water resources might become even more contentious as climate change intensifies. Changes in rainfall patterns leading to decreased/increased flows in different areas at different times may decrease water availability downstream as water is abstracted upstream due to limited-availability. Several intrastate disputes already exist among the states in India, and these could be further aggravated due to climate change. For example, a projected decline in the runoff of many river basins will put additional pressures on interstate and intrastate management of rivers.

 

6. Effects of water scarcity/abundant due to climate change

 

a) Drought: Of the ten most severe drought disasters globally in the last century in terms of the number of people affected, six were from India, affecting up to 300 million people (World Bank Report, 2013). Central Water Commission of India has identified ninety-nine districts forming parts of fourteen states as drought-prone. Most of the drought-prone areas are in Rajasthan, Karnataka, Andhra, Maharashtra, and Gujarat. Drought-prone regions in Andhra Pradesh would experience a 20 percent plunge in the income of dry-land farmers (World Bank, 2008), by 2050, the country is expected to experience a 70 percent decline in annual rainfall during summers.

 

Table 10: Region-wise Concerns with Respect to Water Resources due to Climate Change in India

 

Source: Ministry of Water Resources, 2011

 

As the INCCA Report explains, the percentage change in the spatial distribution of Soil Moisture Deficit Index (SMDI) between the 1970s and 2030s has been used for defining the drought index. It reports an increase in the drought development for those areas of various regions projecting a decline in precipitation or have enhanced level of evapotranspiration in the 2030s. It is very evident from the depiction that the moderate to extreme drought severity has been pronounced for the Himalayan region where the increase is more than 20% in many areas despite the overall increase in precipitation. (MOEF, INCCA, 2010) From a water-security perspective, the country may suffer from hydrological drought due to climate change. Droughts originate due to a lack or deficiency in precipitation, which affects the whole hydrological regime. For example, a precipitation deficiency may result in a rapid depletion of soil moisture that immediately affects agriculture and food production. Hydrological drought depends upon temperature and precipit9tion and is therefore subject to climate change. In states like Rajasthan, a rise in temperature will lead to greater severity of droughts due to higher absorption and decreased precipitation.

 

a) Floods: Increase in temperature, precipitation, and evapotranspiration promote thunderstorms (Katrenberg et al., 1996) and cause flash floods. Riverine floods may result due to monsoon runoff increases and higher precipitation. The INCCA Report predicts, possible floods have been projected using the daily outflow discharge in each sub-basin as generated by the SWAT model, ascertaining the change in magnitude of flood peaks above 99th percentile flow in 1970s and in 2030s. Change in peak discharge equal to or exceeding at 1% frequency in the 1970s and 2030s for various regions indicates that the flooding varies from 10% to over 30% of the existing magnitudes in most of the regions. This has a very severe implication for existing infrastructure such as dams, bridges, roads, etc., in the areas and will require appropriate adaptation measures to be taken up. (MOEF, INCCA, 2010: 29)

 

A wide range of flooding can occur from flash floods, inland river floods, landslides, coastal flooding, storm surges, and glacial lake outbursts (Mirza, 2010).

 

7. Effect on Hydropower Production: With growing energy demands and an untapped hydropower potential, India has been planning to invest in hydropower on a big scale to maintain its targeted 8-9 percent growth rate (Planning Commission, 2013). With the river flows projected to increase in variability and decrease in volume, hydropower generation will become a major challenge. Increased siltation will add to the problem of malfunctioning turbines. Additionally, small hydropower plants, could be damaged by floods with glacial lake outbursts causing a lot of physic damage to the plants, infrastructure, and people. This will have implications for an energy supply which provides about 66 percent of access to electricity in India.

 

The impact of climatic change on seasonal water availability would confront populations with ongoing and multiple challenges to safe drinking water access, sufficient water for irrigation, and adequate cooling capacity for thermal power production. There is uncertainty regarding its management and supply. The real challenge lies in reducing the probability of water-induced conflicts under changing climate (IPCC Scientific Assessment, 1990). For dealing with the impacts of climate change in India and the region will require shifts in adaption strategies and mitigation policy as a precautionary principle.

 

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