Water availability and access are key constraints to poverty reduction and food security. Maintaining enough water for agriculture of reasonable quality will be increasingly difficult due to climate change, competition for water with industries, urban uses and the environment, and the need to produce biofuels. Much of the world is faced with a situation where water supplies for various uses are overallocated, with river flows much reduced, groundwater levels dropping, and important ecosystems threatened - a situation of physical water scarcity. Much of this is driven by agricultural water use. In other parts of the world, availability of water in rivers, wetlands, and aquifers is ample, but access is difficult because people have not found means to develop the water resource - a situation of economic water scarcity. Adaptive management strategies are required to balance decreasing availability with increasing demand, while coping with uncertainties. These include water allocation strategies, development of appropriate types of water storage ranging from small ponds to large reservoirs and from surface structures to managed aquifers, and adopting policies that provide incentives to use water differently. As new water infrastructure is a key strategy for improving secure access for agriculture, the theme considers various benefits and costs of infrastructural development. The overall aim is to maintain equity in water access, agricultural productivity, human health and environmental quality in the face of increasing water scarcity at local, basin and transboundary scales via development of adaptive management strategies, policy responses and tradeoffs.

Source: http://www.iwmi.cgiar.org/research_impacts/Research_Themes/Theme_1/index.aspx