Water scarcity

About: Water scarcity is a research topic. Over the lifetime, 11579 publications have been published within this topic receiving 228756 citations. The topic is also known as: water shortage.

Water allocation mechanisms: principles and examples

Abstract: From the earliest times, water resources have been allocated on the basis of social criteria -maintaining the community by ensuring that water is available for human consumption, for sanitation, and for food production Societies have invested capital in infrastructure to maintain this allocation Yet social change, including changes in (and more understanding of) how goods are distributed, has produced new issues in water allocation Population growth has made water scarcity a major problem in many countries and water pollution, while by no means a recent problem, is more widespread than ever before Traditionally the state has played a dominant role in managing water resources, but inefficient use of water, poor cost recovery for operating and maintenance expenses, the mounting cost of developing new water sources, and problems with the quality of service in agency-managed systems has led to a search for alternatives that make water allocation and management more efficient The authors address some of the basic principles of treating water as an economic good and of allocating it among the sectors After outlining the economic principles behind allocating scarce water resources, they review the actual means of various mechanisms used for allocating water, including marginal cost pricing, social planning, user-based allocation, and water markets Giving examples from experience in several countries, they weigh the pros and cons of different approaches to water allocation, showing that no single approach is suitable for all situations Clearly that state must play an important regulatory role, for example, but how effectively it does so depends on the relative political influence of various stakeholders and segments of society User-based allocation is generally more flexible than state allocation, but collective action is not equally effective everywhere; it is most likely to emerge where there is strong demand for water and a history of cooperation The outcome of market allocation depends on the economic value of water for various uses, but moving toward tradable property rights in water may ease the process of intersectoral reallocation by compensating the"losers"and creating incentives for efficient water use in all sectors

Drought Tolerance and Water Use of Cereal Crops: A Focus on Sorghum as a Food Security Crop in Sub-Saharan Africa

Abstract: Sub-Saharan Africa (SSA) faces twin challenges of water stress and food insecurity – challenges that are already pressing and are projected to grow. Sub-Saharan Africa comprises 43 % arid and semi-arid area, which is projected to increase due to climate change. Small-scale, rainfed agriculture is the main livelihood source in arid and semi-arid areas of SSA. Because rainfed agriculture constitutes more than 95 % of agricultural land use, water scarcity is a major limitation to production. Crop production, specifically staple cereal crop production, will have to adapt to water scarcity and improved water productivity (output per water input) to meet food requirements. We propose inclusion and promotion of drought-tolerant cereal crops in arid and semi-arid agro-ecological zones of SSA where water scarcity is a major limitation to cereal production. Sorghum uniquely fits production in such regions, due to high and stable water-use efficiency, drought and heat tolerance, high germplasm variability, comparative nutritional value and existing food value chain in SSA. However, sorghum is socio-economically and geographically underutilized in parts of SSA. Sorghum inclusion and/or promotion in arid and semi-arid areas of SSA, especially among subsistence farmers, will improve water productivity and food security.

“Virtual water”: An unfolding concept in integrated water resources management

Abstract: [1] In its broadest sense, virtual water refers to the water required for the production of food commodities. Issues relating to virtual water have drawn much attention in scientific communities and the political sphere since the mid 1990s. This paper provides a critical review of major research issues and results in the virtual water literature and pinpoints the remaining questions and the direction of research in future virtual water studies. We conclude that virtual water studies have helped to raise the awareness of water scarcity and its impact on food security and to improve the understanding of the role of food trade in compensating for water deficit. However, the studies so far have been overwhelmingly concerned with the international food trade, and many solely quantified virtual water flows associated with food trade. There is a general lack of direct policy relevance to the solutions to water scarcity and food insecurity, which are often local, regional, and river basin issues. The obscurity in the conceptual basis of virtual water also entails some confusion. The methodologies and databases of the studies are often crude, affecting the robustness and reliability of the results. Looking ahead, future virtual water studies need to enhance the policy relevance by strengthening their linkages with national and regional water resources management. Meanwhile, integrated approaches taking into consideration the spatial and temporal variations of blue and green water resources availability and the complexity of natural, socioeconomic, and political conditions are necessary in assessing the trade-offs of the virtual water strategy in dealing with water scarcity. To this end, interdisciplinary efforts and quantitative methods supported by improved data availability are greatly important.