India’s groundwater challenge*
Groundwater is a dry topic unless you happen to have a dry well. That said, groundwater management involves some of the most complex and socially challenging sets of issues facing India in the 21st century. Furthermore, how those issues are resolved will affect both the environment and the day to day life of most people living in rural and urban areas.
Groundwater is an invisible resource. As a result, both the dynamics of the resource base and the services it produces are often poorly understood. This article focuses first on the broad array of environmental and social services that depend on groundwater. Key aspects of the resource base and emerging problems are presented next. The final section outlines some of the social, ethical and institutional challenges inherent in sustainable management.
Over the past 50 years, expansion of groundwater irrigation has played a lead role in food security. Yields in areas irrigated by groundwater are often substantially higher than yields in areas irrigated from surface sources. In India, for example, research indicates that yields in groundwater irrigated areas are higher by one third to one half than in areas irrigated from surface sources and as much as 70-80% of India’s agricultural output may be groundwater dependent.
Higher yields from groundwater irrigated areas are due, in large part, to its ease of control and reliability. Early studies indicated that water control alone can reduce the gap between potential and actual yields by about 20%. This translates into substantial benefits. Reliability is even more important. Groundwater is a key buffer against drought and normal variations in rainfall. Overall, increased yields from groundwater irrigated areas have translated into substantially higher yields and are thus a major factor in food production at the regional and national levels.
Furthermore, some of the most important food security benefits related to groundwater lie at the level of individual farmers. The vulnerability to natural hazards of different groups in society, including those that threaten food security, can be explained by their access to networks of key productive and social resources. For rural populations, groundwater is among the most important of these resources.
Households with access to key resources are able to build support systems that reduce their vulnerability to natural hazards. Groundwater irrigation reduces the risk that investment in labour, seed, fertilisers, pesticides and other inputs will be lost due to drought or the variability of precipitation in normal years while higher yields enable households to generate surpluses. As a result, households with access to groundwater tend to have higher levels of savings and are able to make investments in other productive resources or activities.1
When drought strikes or there is a gap in rainfall these households have a dual advantage. First, they are far less likely to suffer losses than those without access to groundwater. Second, even if ‘the well runs dry’, households that own wells have often been able to save cash or food and invest in alternative sources of income. As a result, they have assets that can carry them through periods of scarcity or crisis.
Groundwater is a highly important source of domestic water supply. In India, roughly 80% of rural water supply for domestic uses is met from groundwater. The importance of potable drinking water is clear. As in the case of other uses, however, this is only a portion of the value of groundwater as a source of domestic supply. Wells in villages and towns free people, particularly women, from long daily walks to fetch water from springs or rivers for livestock and domestic uses. This frees time and labour for other activities. Furthermore, since water no longer has to be carried over long distances, more is often used. This can have major health benefits. In addition, because of the filtering nature of the soil and frequent long residence time underground, groundwater is commonly much cleaner than surface sources.
Groundwater is a key resource for poverty alleviation and economic development. Evidence indicates that improved water sources generate many positive externalities in the overall household micro-economy. In areas dependent on irrigated agriculture, the reliability of groundwater sources and the high crop yields generally achieved as a result often enable farmers with small landholdings to increase income. In India small and marginal farmers (those having less than 2 hectares) own 29% of the agricultural area. Their share in net area irrigated by wells is, however, 38.1 % and they account for 35.3 % of the tubewells fitted with electric pump sets.
Thus, in relation to operational area, small and marginal farmers tend to have proportionally more irrigated land than larger farmers. With productivity on irrigated lands being much higher than that on non-irrigated tracts, better access to irrigation for small and marginal farmers can significantly reduce poverty.
The positive economic impact of groundwater development extends beyond well owners. Access to groundwater stabilises the demand for associated inputs, and leads to the spread of support services for pumps and wells, creating a base for small scale rural industries. Furthermore, the spread of groundwater irrigation can increase demand for labour. In India, for example, labour accounts for approximately 44 % of the cost of installing a well and the additional indirect employment created on every hectare of irrigated land through increased agricultural activity is approximately 45 days per hectare. Therefore, the expansion of groundwater irrigation has significant ripple effects, creating employment throughout rural economies.
The equity impacts of groundwater development for irrigation are, however, not all positive. Modern tubewell and drilling technology tends to be capital intensive. As a result, early exploiters of groundwater have typically been large farmers who produce surpluses for the market Small holders growing subsistence crops often depend on supplementary groundwater irrigation using a variety of man and animal-driven water lifting devices from shallow, open wells. The expansion of energised pumping technologies tends to draw water levels down, driving shallow wells and muscle-driven devices out of business. This was, for instance, the case throughout the Gangetic basin and other parts of India during the 1960s.
As water levels began to decline, some state governments in India attempted to implement administrative regulations, such as selective credit controls, restrictions on electricity connections and siting and licensing rules. These regulations did not affect landowners who were able to install tubewells early, but limited the entry of latecomers – particularly the resource poor who depended on credit or access to subsidised electricity in order to afford the capital cost of operating and installing pumps. In addition, the economically and politically powerful were generally able to bypass regulations via ‘adjustments’ with officials or by depending on their own financial resources for well construction and operation.
Equity considerations are generally a major point of tension as management needs emerge. Rapid unrestricted development of groundwater has reduced poverty by giving the poor access to a key resource for production. This same pattern of unrestricted development, however, is the primary cause of over-extraction and quality problems now emerging in many parts of the world. As groundwater problems grow, marginal populations are often the first affected. Water level declines, for example, have the largest economic impact on individuals who are unable to afford deeper wells – i.e. the poor.
The poor are also the least well positioned to protect their interests if groundwater extraction must be reduced. Restrictions on new wells tend to affect them much more than wealthy communities where wells were installed much earlier. Wealthy individuals and communities are also often able to work around these and other types of management restrictions while poorer communities (who generally lack political as well as economic leverage) have less ability to do so. In sum, there is an inherent tension between equitable access to groundwater for all sections of society and sustainable management of the resource base.
The array of environmental services or values dependent on groundwater are often poorly understood. Environmental concerns related to groundwater generally focus on the impacts of pollution and quality degradation on human uses, particularly domestic supply. Development impacts on the groundwater environment are, however, different from the numerous environmental services provided by groundwater resources in their natural state.
What are some of the most important environmental services provided by groundwater? The following list, while not exhaustive, illustrates the degree to which many environmental values are dependent on groundwater:
* Catchment baseflow derived from groundwater discharge is perhaps the most evident environmental value associated with groundwater. In many areas springs and the dry season flow in rivers depend heavily on groundwater.
* Instream fisheries and aquatic ecosystems: Instream flows are critical for the maintenance of fisheries and aquatic ecosystems. As previously noted, groundwater contributions can be a dominant source of water for instream flows, particularly during droughts and dry seasons.
* Inland wetlands: Wetlands are some of the most productive and biologically diverse inland ecosystems. In many, if not most, cases water availability in wetlands depends on high groundwater levels.
* Surface vegetation: Groundwater levels directly influence many vegetation communities. Phreatophytes, plants that derive a major portion of their water needs from saturated soils, can be the dominant vegetative species in ecosystems where groundwater levels are shallow. They often form critical wildlife habitat and may serve as important sources of food, fuel and timber.
In many areas the environmental values dependent on groundwater conditions are closely intertwined with a broad array of human use patterns. Groundwater is an integral part of linked hydrologic, ecologic and human use systems. Changes in surface water use, groundwater use or vegetation can send ripple effects throughout these interlinked systems – often with effects that are difficult to predict.
Throughout much of South Asia, groundwater development has proceeded at an exponential pace over the past four decades. In India, the number of shallow tubewells doubled roughly every 3.7 years between 1951 and 1991. Rapid development has engendered its own set of issues. In many arid and hard rock zones, overdraft and associated quality problems are increasingly emerging. Although the area currently affected by groundwater overdraft may be limited, blocks classified as dark or critical increased at a continuous rate of 5.5% over the period 1984-85 to 1992-93. If continued at this rate, the number would double every 12.5 years. This implies that by the year 2017-18 (25 years from 1992-93), roughly 1532 blocks or 36% of the 4248 blocks in the listed states would be dark or critical.
Overdraft is, however, only a fraction of the management challenge associated with groundwater. Large areas, particularly in the command of surface irrigation systems suffer from waterlogging and associated salinity or alkalinity problems. Furthermore, development impacts on the environment and non-agricultural users can be major even where overdraft or waterlogging are absent. Seasonal watertable fluctuations can affect shallow wells, low season flows in surface streams, and pollution loads. The impact of this on drinking water availability, the poor and the environment can be major.
Furthermore, it is important to recognize that overdraft and water level declines typically affect the sustainability of uses that are dependent on groundwater long before the resource base itself is threatened with physical exhaustion. Many uses and environmental values depend on the depth to water – not the volume theoretically available. In the case of the Ganges basin, for example, water level declines would exclude the poor from access to groundwater (due to the cost of increasing well depth) and would reduce base flows in streams long before the aquifer would face any threat of depletion. The Ganges basin contains, in some locations, over 20 thousand feet of saturated sediment. Dewatering of only the top few tens of feet would, however, have tremendous economic and environmental impacts.
Beyond overdraft and water level declines lie the questions of water quality and pollution. Pollution or quality declines can cause reductions in water availability that are far less reversible than overdraft. Non-point source pollution from agriculture and other sources combined with point source pollution represents a major management challenge. Furthermore, not all quality problems are human induced. Probably the most extensive case of arsenic poisoning from groundwater is that of Bangladesh and West Bengal. Arsenic occurs naturally in the groundwaters abstracted from the alluvial deltaic sediments of the Ganges-Brahmaputra-Meghna river systems and an area around 75,000 km2 is thought to be affected by groundwater with high arsenic concentrations.
Despite the widespread nature of emerging problems, how extensive groundwater mining and pollution problems really are remains uncertain. Official statistics on the number of blocks where extraction is approaching or exceeds recharge may be misleading since great uncertainty exists over the reliability of published extraction and recharge estimates. Furthermore, even the basic water table measurements on which these estimates rest may, in some cases, be open to question.
Uncertainty is also inherent in relation to the extent of pollution. Clearly pollution loads have increased substantially over recent decades with increases in the use of agricultural chemicals, industrial discharges and urban waste. At the same time, no comprehensive data sets are available that would allow identification of the extent and distribution of different pollutants. Quality problems are also often identified ‘after the fact’. Again the arsenic case is illustrative. This was only recognized as a widespread problem when large scale cases of arsenic poisoning began to appear.
A critical challenge in interpreting both quantity and quality problems relates to understanding of the resource base and its dynamics. Many individuals, groundwater professionals included, conceptualize groundwater as flowing smoothly through the earth with rapid recharge from rainfall and relatively uniform water quality. In reality, however, complex rock formations and differential recharge rates result in far more complicated dynamics. These, in turn, greatly complicate understanding of resource conditions.
Two examples are illustrative. In Rajasthan, local communities often suggest that groundwater overdraft problems are alleviated whenever rainfall is above normal. In many cases, however, the water they pump has been underground for hundreds and, in some cases, as much as 20,000 years. Recharge dynamics depend on the permeability of soils and flow patterns are often only weakly related to short term fluctuations in precipitation.
Similarly, major quality problems can depend heavily on very localized conditions. Arsenic, for example, is preferentially mobilized under reducing conditions. As a result, the amount of arsenic encountered in water from a given well can depend on the amount of organic matter available precisely where the well was drilled. A well that happens to pass near a tree trunk buried deep underground may have substantially more arsenic than a well drilled only a short distance away.
Debates over the need for management are often clouded by uncertainty over the extent and nature of emerging problems. At the same time, delays in initiating management can have irreversible implications. Once polluted, groundwater aquifers are often impossible to remediate. Pollutants can become attached to the aquifer matrix (the sand, soil and rocks) and serve as a continuous source of contamination. Overdraft can lead to aquifer compaction (reduction of pore spaces) making recharge impossible. Even if recharge is technically feasible and sufficient water is available, the low flow rates characteristic of many fine grained aquifers can make the process so slow that little can be done on a human time scale.
As a result, overdraft is often equivalent to mining a resource such as oil that can not be replenished. Even experts often have difficulty identifying the emergence of irreversible problems until after the fact. Managing uncertainty is thus a major part of any groundwater management equation.
Groundwater is an invisible, poorly understood resource, yet one that is critical to a wide variety of social, economic and environmental services. Pollution and declining water levels represent direct threats to the sustainability of environmental, domestic, agricultural and industrial uses dependent on groundwater. In addition, as demands grow and the limits of sustainable extraction become evident, competition between agricultural and other users is increasing rapidly. This can generate competitive extraction between individuals. Each person extracts as much groundwater as possible in order to capture benefits for themselves before the resource is exhausted. The net result can be a spiral of growing demands and decreasing availability. Competition is, thus, a critical social issue that must be addressed in order to manage groundwater on a sustainable basis.
Technical options for resolving competition over groundwater are generally limited. In most cases communities and groups affected by groundwater overdraft advocate aquifer recharge. Throughout India the real viability of this option is often limited. In much of Gujarat, for example, estimates indicate that increases in recharge could only reduce overdraft by 10% and in many other areas little unutilized surface water is available that could be recharged. Even where water is available, the timing and distribution of rainfall limit the ability to recharge aquifers. Recharge is a slow process limited by the infiltration rates of water through soil and underlying formations. Precipitation, in contrast, is often highly seasonal and occurs in brief bursts little of which can be stored for recharge.
Beyond the technical limitations in recharging aquifers, three concepts are central to understanding the social challenges inherent in resolving competition over groundwater resources. These are:
* Interdependency: Groundwater is a lynchpin that links and creates points of interdependency between agricultural, environmental and econoic systems. Environmental values, access for the poor to water, food security during drought years and the economic viability of different crops may, for example, all depend on the maintenance of specific water table or water quality conditions. These conditions are, in turn, often dependent on water use patterns. Recharge from ‘inefficient’ surface irrigation systems, for example, often helps to maintain high groundwater levels and, through that, base flows in rivers, groundwater access for the poor and so on.
* The public good nature of many groundwater services: Individual users can only capture the ‘extractive’ values associated with groundwater, i.e. products produced by pumping and using it in a specific application. This extractive value does not, however, reflect the environmental, drought buffer and other services produced by groundwater when it is left in the aquifer. These services are public goods – while individuals may benefit from them, the conditions depend on the cumulative actions of all users. There are strong economic incentives for individuals to overpump groundwater or ignore their contribution to pollution of an aquifer. This leads to chronic undervaluation of groundwater when it is sold in water markets or analyzed using standard economic approaches.
* Scale: In most cases, groundwater cannot be managed at a very local scale. Aquifers generally extend under regions encompassing anywhere from tens to thousands of villages. As a result, aquifer dynamics limit the impact individuals or villages can have on groundwater conditions. At the same time, approaches to management implemented through state agencies are often difficult to adapt in ways that reflect local or regional variations in groundwater conditions and use.
In some parts of the world, notably the United States, the approach to groundwater management hinge on a combination of private rights and regulatory mechanisms. This type of approach attempts to resolve competition by providing a measure of security for all users by specifying individual use rights and using regulation to address public good aspects. In some cases groundwater rights are established that specify the volume individuals are allowed to pump, the types of uses permitted and whether or not the water can be sold to other users. Water markets are widely advocated as a mechanism for ensuring water is allocated to the highest value uses wherever transferable water rights have been established.
Approaches based on regulation and the establishment of individual water rights and water markets face tremendous challenges in India. On a purely practical level, how groundwater rights could be established, monitored and enforced given the millions of wells and conditions in rural India, is far from clear. Regulation would also be difficult and probably highly inequitable in practice. A model bill for groundwater regulation was initially circulated by the Central Ground Water Board in the early 1970s. It proposes a highly centralized system of regulation by state agencies. Modified versions of this have now been adopted in a few locations in India but little implementation has actually occurred.
Beyond the practical limitations of approaches based on individual rights and regulation by the state, however, it is important to recognize the inherently incomplete nature of approaches based on rights, regulation and water markets. It is difficult to define water rights (whether allocated to individuals or communities) in ways that capture the interdependent and public good nature of the services produced by groundwater. When rights are transferable through market mechanisms, the values reflected in the market still tend to be the direct use values rather than the public goods. When attempts are made to regulate groundwater use and transfers in ways that protect public goods approaches rapidly become complex and inflexible – unable to respond to the diverse conditions encountered at local levels or to the dynamic nature of conditions.
Because of the above limitations, approaches to groundwater management need to reflect the political nature of such decision making in order to be effective. The public good nature of groundwater services and interlinked and often poorly understood character of systems dependent on groundwater tends to generate substantial debate over management approaches and objectives. How this competition is resolved generally depends on the ability of different groups to first understand the nature of emerging problems and management options and second to insert their views into the decision making process that determines management actions.
Access to information, economic power and the ability to organize greatly influence the ability of different groups to effectively engage in this type of dialogue. Under current conditions, groundwater management decisions are effectively based on economic power – the ability of individuals to afford the costs of deepening their own wells and keep on pumping. Resolving this probably requires approaches based on balance of power concepts and explicit recognition of the political nature of management needs.
Key points of leverage that may encourage the development of effective groundwater management systems could include: (i) improved access to information; (ii) legal standing for groups and individuals to force protection of public interest values; and (iii) the creation of management organizations capable of functioning at an intermediate scale (i.e. between the village and the state).
*. This article is based on three primary sources (listed below) and draws material from them. References for specific information and figures in the article can be found in the three primary sources:
Marcus Moench (1996), Groundwater Policy: Issues and Alternatives in India, International Irrigation Management Institute, IIMI Country Paper, India, No. 2, Colombo, pp. 61.
World Bank (1998), India: Water Resources Management Sector Review, Groundwater Regulation and Management Report, Washington D.C., pp. 98.
ISET & UNDESA (1999), Groundwater and Society: Resources, Tensions & Opportunities, Themes in Groundwater Management for the 21st Century, in press.
1. The reverse is equally true: e.g. households with better access to social and economic resources are generally better able to afford the cost of obtaining groundwater access. Wells can be expensive.