Maite M. Aldaya

The water footprint assessment manual : setting the global standard

This manual presents a scientifically rigorous method to help companies understand their dependency and impact on global water resources, and offers guidance on response strategies that conserve water for industry, communities, and nature. It contains the global standard for water footprint assessment as developed and maintained by the Water Footprint Network. It covers a comprehensive set of definitions and methods for water footprint accounting. It shows how water footprints are calculated for individual processes and products, as well as for consumers, nations, and businesses. It also includes methods for water footprint sustainability assessment and a library of water footprint response options. The water footprint of a product is the volume of freshwater used to produce the product, measured over the fully supply chain. It is a multidimensional indicator, showing water consumption volumes by source and polluted volumes by type of pollution; all components of a total water footprint are specified geographically and temporally.

Understanding the impact of crop and food production on the water environment—using sugar as a model

The availability of fresh water and the quality of aquatic ecosystems are important global concerns, and agriculture plays a major role. Consumers and manufacturers are increasingly sensitive to sustainability issues related to processed food products and drinks. The present study examines the production of sugar from the growing cycle through to processing to the factory gate, and identifies the potential impacts on water scarcity and quality and the ways in which the impact of water use can be minimised. We have reviewed the production phases and processing steps, and how calculations of water use can be complicated, or in some cases how assessments can be relatively straightforward. Finally, we outline several ways that growers and sugar processors are improving the efficiency of water use and reducing environmental impact, and where further advances can be made. This provides a template for the assessment of other crops.

Data and Limitations

The purpose of this chapter is to provide a detailed description of data sources and the limitations of the study based on these data.

Bringing the Analysis to the Policy Context

This chapter attempts to bring the evaluations reported in Chaps. 5 and 6 to the policy context, by looking at economic performance, variations and causal relationships associated with agricultural and water policies. We start by reviewing changes in land productivity, both rainfed and irrigated, from a temporal and spatial perspective. Since agricultural policies are markedly different across Spanish provinces, and since the EU Common Agricultural Policy also changed over the 1996–2006 study period, our spatial and temporal analysis yields conclusions about how Spanish agriculture has changed, notably in irrigated vs. rainfed farming, with profound impacts on the patterns of water use in agriculture. In the second section, we offer a dynamic analysis of the economic incentives for inter-basin and intra-basin surface transfers, with water scarcity being the major driving force. Water allocation and economic efficiency across regions and basins are the main focus of this section.

Spain’s Water Footprint

The purpose of this chapter is to report the footprint evaluations obtained at the national, regional and river basin levels for 1997–2006. The procedures and data sources used to generate the results were presented in Chaps. 3 and 4. A similar though slightly different approach was used in the case of the Guadiana river basin, which can be found in Aldaya and Llamas (2008a, b, 2009). This chapter first of all reviews the water footprint on a national scale and then focuses on the Guadiana river basin.

Net Virtual-Water “Flows”

Global trade establishes an “invisible” and indirect link between water demand and water consumption sites. The literature on virtual-water “trade” has emphasised the options available to arid and semiarid countries to use international trade to deal with water resources scarcity (Allan 2003; Yang and Zehnder 2005; Chapagain et al. 2006a; Ma et al. 2006; Comprehensive Assessment of Water Management in Agriculture 2007; Yang and Zehnder 2007; Aldaya et al. 2008a, b; Novo et al. 2009). However, determining whether this strategy is economically and environmentally efficient will depend on whether the real opportunity cost of water resources is properly internalised, and whether the trade is actually based on differences in competitive advantage among trading partners. It is also doubtful that “virtual-water trade” is termed a “strategy”, because no government or agent pursues it directly. Rather, it is a process that is naturally linked to trade and the exchange of goods, with the exception of Arid and Semi-Arid countries in the Middle East and North Africa (MENA) region.