Karin Erika Kemper
World Bank (South Asia Sustainable Development Department), 1S1S H Street NW, Washington, DC 20433, USA
Groundwater is one of the key resources enabling agricultural development, providing farmers from Argentina and India to China with access and flexibility in water application that usually cannot be matched by surface water resources unless a farmer lives in close proximity to a perennial river or lake. No wonder, therefore, that groundwater is so popular in agriculture, as already highlighted in the regional chapters in this volume. In fact, groundwater irrigation now surpasses surface water as the main source of irrigation water in many regions. Because of the growth in groundwater irrigation, agriculture now accounts for an estimated 70% of total groundwater use with only 20% and 10% going to industry and residential uses, respectively (Brown et al., 1999). However, the large-scale expansion in agricultural groundwater use is leading to the resource being overexploited in an increasing number of countries. Intensive exploitation of groundwater for agricultural uses in India, China, North Africa and the Arabian peninsula exceeds natural replenishment by at least 160 billion cubic metres per year (www.wateryear2003.org).
While published cases of agricultural groundwater use and overuse are impressive, it is important to note that groundwater in some hydrogeological settings is not used alone, but in conjunction with surface water, for instance, as a supplement when irrigation schemes are undermanaged and farmers seek reliability and flexibility provided by their own wells. This, added to the fact that rural groundwater use is generally unmonitored, means that worldwide use in agriculture is probably underestimated - as highlighted in the work on South Asia, China and sub-Saharan Africa in this volume - because often only 'pure groundwater irrigation areas' are counted.
The development of drilling technology allowed the spreading of intensive groundwater abstraction in agriculture since the 1970s. This was not accompanied simultaneously by the evolution of institutional arrangements and investments in management agencies. In most countries, groundwater has therefore traditionally been dealt with in a laissez-faire mode, i.e. farmers, be it in Brazil or Pakistan, have used groundwater to irrigate their crops, typically without attention to the
©CAB International 2007. The Agricultural Groundwater Revolution:
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sustainability of the resource. The effect has been twofold. On the one hand, this unregulated groundwater use has permitted spectacular expansion of agricultural growth and lifted millions of people out of poverty (World Bank, 2005). On the other hand, many aquifers worldwide are now under severe stress and groundwater cannot wholly sustain the production that has been initiated. In these over-exploited areas, it has also become clear that introducing aquifer management is a time-consuming and politically challenging endeavour. As this chapter shows, there are a number of countries worldwide that have started to proactively manage their groundwater resources. However, there are as yet few well-established examples of good practices and effective groundwater management in developing countries. Even more than in regard to surface water management, groundwater institutions are in an evolutionary phase and no simple blueprints for management success are appropriate. The reasons for this state of affairs which relate primarily to the nature of the groundwater resource itself will be amply discussed below.
The objective of this chapter is to (i) discuss the special nature of groundwater and the resulting challenges for its effective management in agriculture; (ii) provide an overview of the institutional arrangements and instruments available for groundwater management in a variety of settings worldwide; and (iii) highlight some key issues regarding the way forward in groundwater management for the future.
The paper focuses primarily on the quantity dimension of groundwater overabstraction and briefly touches on pollution management issues, which are even more complex.
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