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United States Department of Agriculture

Agricultural Research Service

Research Project: Developing Sustainable Cropping Systems to Improve Water Productivity and Protect Water and Soil Quality in Irrigated Agriculture

Location: Water Management Research

Title: Summaries and considerations

item Schwabe, K -
item Albiac, J -
item Andreu, J -
item Ayars, James
item Caiola, N -
item Hayman, P -
item Ibanez, C -

Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: August 8, 2012
Publication Date: May 5, 2013
Citation: Schwabe, K., Albiac, J., Andreu, J., Ayars, J.E., Caiola, N., Hayman, P., Ibanez, C. 2013. Summaries and considerations. In: Drought in Arid and Semi-Arid Regions: A multi-disciplinary and Cross-Country Perspective. New York, Springer. p. 471-507.

Interpretive Summary: Climate change will have a significant impact on water supply throughout the world with droughts becoming longer and occurring more frequently. A conference was held at the University of California, Riverside in 2010 to explore drought management strategies and the effects of drought in arid and semi-arid areas of the United States, Spain, Mexico, South Africa, and Australia. A book was written as a compilation of the 25 presentations given during this conference. The goal of the book was to increase our knowledge of drought, its impacts on natural and man-made systems, and potential strategies for effectively addressing droughts by highlighting experiences, strategies, and scientific research associated with droughts in the countries represented by the participants. This chapter provides a summary of the work described in each of the five disciplines: agronomy, irrigation technology, and water supply; ecology; hydrology and water resource systems; economics; and water management and policy represented at the conference. The observations from the studies presented during the conference indicate that there are ample reasons to be optimistic about how society might address drought in the future. It appears that there is agreement among the scientists, water managers and policy makers involved with this book on the main drivers of drought. This agreement is important as a necessary condition for the development of effective and successful drought management plans and policies. It also appears there is ample opportunity to reduce the per capita water use and increase or extend water supply through several methods e.g. efficient on farm management and water markets and water banking. Two other observations are required to understand the requirements for effectively managing drought. The first is that managing droughts efficiently and effectively requires real-time information on the biophysical elements of drought and the institutional arrangement to make decisions in an expeditious manner if required. The second point is the need for participatory and transparent approaches to developing and administering drought policies.

Technical Abstract: This chapter summarizes the 25 presentations that have been compiled as chapters in a book based on a drought conference held at the University of California, Riverside in 2010. The chapters were grouped into five major areas within the book: agronomy, irrigation technology, and water supply; ecology; hydrology and water resource systems; economics; and water management and policy. Studies in Australia, Spain, South Africa, and the United States discussed the technological and agronomic responses to drought. These included increasing water supply through reservoir construction, desalinization of saline water, using untreated wastewater, drilling wells, and abstraction from surface water. In general, there was a substantial additional cost associated with these alternatives. Water conservation and demand management in agriculture included changing crop patterns, varying planting densities, switching irrigation methodologies, deficit irrigation, and selective pruning of perennial crops. However, implementing some of these strategies may develop some unintended consequences e.g. modernizing irrigation systems to improve efficiency resulting in increased irrigation from the “conserved water”. The results in the ecology analysis determined that most freshwater ecosystems in semi arid regions are particularly vulnerable, due to the intense, frequent and synergistic effects of natural and human induced disturbances. Looking at the studied cases, the main observed responses of the aquatic ecosystem to increasing water stress are the loss of ecosystem integrity, the alteration of its functionality, and the reduction of ecosystem services. The most frequently demonstrated effects of drought on fish were population declines, loss of habitat, changes in the community, negative effects from changes in water quality, movement within catchments, and crowding efficient into micro-habitats. Future research should focus on quantifying the ecological effects of water scarcity at different spatial and temporal scales, developing specific ecological indicators of water stress, and also on determining and modeling the influence of altered river flows and rainfall patterns in maintaining biodiversity and ecosystem functions and services. Water resources system studies concluded that in the past, response to drought events has been to develop water infrastructure to provide more reliable supply and reduction in vulnerability for water dependent activities. The result is a water resource system whose yields and performances depend not only on hydrology but also on infrastructure and management. A common conclusion is that water resource systems, in arid and semi-arid regions with water scarcity and prone to hydrological droughts, must be designed and managed with the permanent objective of preparedness for droughts anticipation and mitigation; that is, with a proactive approach rather than the classical reactive approach. A summary of the economic analysis of Australia and California provide evidence that water trading as a mechanism to allocate water from low to high profit uses can be a valuable drought management strategy. The hydro-economic modeling from California also provided evidence that there are likely to be economic benefits from investments in infrastructure to allow conveying and storing water in ways that can reduce drought impacts and reduce dry period supply constraints. Results show that water reallocation and technology adoption are essential components that reduce the hydrologic and economic impacts of water scarcity. The policy papers highlighted that drought management and water policy are being developed with concern over climate change and increased population pressures. These responses include a variety of supply and demand side measures with a movement towards finding more locally reliable supplies that likely include wastewater reuse and desalinization. Uncontrolled pumping from groundwater systems is becoming less acceptable, while opportunities to increase water use efficiency are increasingly being explored. As water becomes scarce, governments and water agencies are realizing the importance of better monitoring systems, and the potential benefits of having access to multiple water supply sources, including those that would become available via water markets.

Last Modified: 7/24/2014
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