Beyond crop per drop:

Water scarcity is seen as a major risk in many parts of the world, and water crises are consistently cited as among the top global risks. Irrigated agriculture is by far the largest water use worldwide, accounting for an estimated 70 percent of total freshwater withdrawals. In many drier countries, agricultural water use accounts for more than 90 percent of total withdrawals. As water becomes increasingly scarce, the management of agricultural irrigation moves to the center of water management concerns. Without advances in management and more integrated policy making in both developed and developing countries, water scarcity and related water problems will significantly worsen over the next several decades. Yet the question of how best to adapt agricultural water management is complicated, not least because irrigated agriculture is at the center of two large and conflicting trends. This report aims to shed further light on these issues: first, by clarifying some of the underlying concepts in the discussion of agricultural water productivity and efficiency; second, by reviewing and analyzing the available methods for assessing water productivity and efficiency; and, third, by discussing their application and relevance in different contexts. As the background for this analysis, the report highlights the central role of water use in irrigated agriculture and its link with increasing water scarcity. This is discussed in the context of the transition from an expansionary water economy to a mature water economy. The report further develops this framework to reflect water management issues in irrigated agriculture. The expansionary phase is characterized by readily available water supplies to meet the growing demand for irrigation water as agricultural production increases. In the mature phase, the intensifying competition for water tends to be perceived as an increasing scarcity of water. In the transition from the expansionary phase to the mature phase, the interdependencies among water users increase, and the hydrologic setting and the rising externalities need to be considered. The policy objective of increasing agricultural production needs to be balanced with the new objective of water conservation. The interventions, which in the expansionary phase were focused on engineering and technological interventions to expand agricultural water supplies, need to increasingly incorporate demand-side interventions and options for reallocations, and to further develop context-specific policy and institutional arrangements as the water economy matures