FAO predicts that additional water development will be needed in order to accommodate the needs of another 2 000 million people by 2030. If gains in water productivity can be maintained, the pressure on resources can be reduced and the scope for transfers to other users expanded. The increase in agricultural water productivity has been the result of strategic investment in water development but also in research and development and in agricultural extension. The current investment trends in these components show a sharp decline. The future of agricultural water management will depend on maintaining levels of investment in key areas of the production chain, not jsut in water control infrastructure alone. In this respect, it is the quality of the investment, rather than the quantity, that will be critical.
Given that demands for food are non-negotiable, the only scope for improving overall water management will hinge on the continued improvement of water productivity in existing agricultural systems (rainfed and irrigated). Therefore, investment should comprise a strategic package combining: research investment to develop more productive biological materials; improved agricultural practices; capacity building for farmers and users; promotion of agricultural trade to improve global productivity; and new resource development where necessary.
Water requirements for an anticipated stabilized population of about 8 000 million are not easy to predict. The precise amounts of water that must be available at specific locations for sustainable crop production have their own spatial and temporal variability. The problem is compounded by uncertainty with respect to the amount of water required to maintain ecological integrity and for the recharge of overexploited aquifers. Finally, the impacts of climate change on raw water availability and the demands of agriculture remain conjectural. Considering all these unknowns, providing enough water for the global production of adequate food supplies represents an enormous challenge, particularly in regions and countries where water is already scarce. This uncertainty about future water availability and the demands to ensure food security frustrates decision-making on investments for agricultural water management. The questions that need to be answered are:
® How much additional storage capacity in dams and reservoirs is required?
® How can nations and regions ensure the sustainable use of pumped groundwater that is critical to agricultural production?
® How can additional sources of water, such as municipal and industrial wastewater, be best used in irrigated agriculture without adverse effects on human and ecological health?
This paper has discussed the link between irrigated agriculture and poverty alleviation and rural development. Indirect effects of irrigation on rural development have been notable, especially through the creation of off-farm employment opportunities for poor people. However, other investments, e.g. in roads and markets, could often be of even greater direct value to rural development. Thus, for investment to have the greatest possible impact on poverty alleviation, governments and funding agencies are faced with difficult choices between direct investment in agricultural water infrastructure or leading investment in market creation and access.
System-level improvements in irrigation and drainage infrastructure and in the institutional and policy arrangements for managing these systems will enhance water productivity and hence food security. However, the greatest benefits are expected from integrated crop and resource management. These will accrue when the three components of plant breeding, agronomic improvements, and changes in the operation and management of irrigation facilities work together so that the potential benefits of new crops and varieties are fully realized. There are few successful examples of this three-way collaboration. Its realization amounts to reinventing agricultural water management. Equally, improved agronomic practices in farmers fields, such as zero tillage and raised beds, will also lead to greater water productivity in agriculture. However, the adoption and adaptation of these techniques has been slow.
IWRM has been heralded as a framework for planning, organizing and controlling water systems in order to balance the views and goals of all relevant stakeholders (Grigg, 1999). This definition includes two dimensions of interdependence: social (balancing views and goals of stakeholders) and ecological (managing multiuser water systems). In the past, water had two main purposes: for domestic uses and to produce food for growing populations. Today with the competition for water, such simple objectives are no longer acceptable. Advocates of IWRM believe that a move to a more sustainable irrigation sector depends on well-functioning WUAs. However, it has proved difficult to start WUAs. Before WUAs can be set up successfully, it is necessary at a minimum to assess the water resources, assign water rights to legitimate users, and define institutions for administering the water rights. Conflicts of interests between the various stakeholders make it difficult and expensive to satisfy these three prerequisites. Moreover, there is growing evidence that irrigation management transfer risks aggravating rural poverty unless a pro-poor mode for this process is designed and implemented (van Koppen et al., 2002).
A critical issue in terms of the resource base is the overabstraction of surface and groundwater resources, which in many locations appears to be unsustainable. In discussing sustainable management of groundwater resources, some people suggest that exploitation of the groundwater resource beyond its recharge level can be justified if it initiates sustainable development by using the income from pumped groundwater for useful purposes. Nevertheless, by the advancing water-saving technology, promoting land management and other long-term benefits, a contribution to sustainability can be claimed (Kinzelbach and Kunstmann, 1998, Barker et al., 2003). The strategic choice of how much environmental degradation can be justified for the sake of increasing food security or reducing poverty is a difficult one. The tradeoff is neither simple nor direct since alleviating poverty can in fact prevent environmental degradation.
These conclusions indicate that, unless national governments and funding agencies make several strategic choices regarding agricultural water management, the agriculture sector will not be in a position to maintain current water allocations for the strategically important food production produced by irrigation.
For national governments, the choices imply:
1. Accepting the fact that there is no single solution for maintaining food security when water is scarce. All sources of water (rainwater, canal water, groundwater and wastewater) are important. They can all be developed under the right set of conditions, and additional storage capacity and recharge of groundwater resources form part of the long-term solution.
2. Finding the best options for specific conditions. Good and poor-quality land can be used for the production of food crops and other commodities, and the best combination of land, crop and water is site-specific but not ignore the inherent productivity of natural ecosystems.
3. Realizing that the link between irrigated agriculture and rural development is not always straightforward, rural development may be better served by investments in sectors other than irrigation.
4. Adopting natural resource based policies and institutions that encourage the integration of crop and resource management in order to identify the best location-specific options.
5. Facilitating and supporting actively the development of improved varieties as part of the solution for future food security.
6. Supporting actively the application of seasonal climate predictions in order to create the best combination of crop and resource management for the anticipated climate conditions.
7. Investing in irrigation modernization as an ongoing process, while recognizing each systems specific comparative advantages. The aim of modernization should be to make the water delivery system and its management flexible enough to take full advantage of new technologies and crop varieties.
For donor agencies, the choices for strategic investments in agriculture imply:
1. Accepting agriculture as the sector where the potential for generating water savings through productivity gains is greatest.
2. Linking global goals and global finance with local initiatives and local needs. Funding should be tailored to the specific physical and socio economic settings