Water Footprint
In recent years water footprinting has increasingly gained attention. In many regions it is recognized that agricultural and industrial processes increase the water scarcity which can lead to severe effects on the environment, such as diminished vegetation and biodiversity loss. Water scarcity also poses a risk concerning sufficient food supply and diminishes the long-term availability of water resources. Water scarcity is thus considered to be a major environmental issue.
A range of different terms are used in the context of water use and water consumption. So far, there are no standard definitions available. The distinction between water consumption and water use is significant. While the water use includes the water input and all types of water uses in the life cycle of a product (e.g. cooling, turbination, irrigation etc.), the water consumption describes only the amount of water that is lost to a system as a result of activities such as the production of a good or the cultivation of crops. Water consumption is sometimes also called “net water use” or “net water withdrawal”.
The water consumption itself can be distinguished according to the type and origin of the water source. It is generally differentiated into blue, green and grey water. Green water refers to the amount of rainwater used; blue water stands for fresh water from lakes, rivers and ground water.
The analysis of the water consumption concentrates mainly on the quantity of the water. The degradation of the water quality is assessed with separate impact categories in LCA (e.g. ecotoxicity or eutrophication). The so called grey water consumption however an indicator for the harmfulness of the substances emitted, although it is not damage oriented.
Different life cycle impact assessment methods (LCIA) are available for characterising the amount and impact of water usage. ESU-services has elaborated an approach for the assessment of water use and water consumption in the framework of the Ecological Scarcity Method. This method is recommended by the European research institute DG-JRC in Ispra. ESU-services has further developed a methodology for inventorying water use and consumption on a country level. This allows for the application of different LCIA methods, e.g. the ecological scarcity method. This LCI method is also applied for the investigation of ESU data-on-demand and new public inventories of hydro power.
Publications
Muñoz I., Flury K., Jungbluth N., Rigarlsford R., Milà i Canals L. and King H. (2013) Life Cycle Assessment of bio-based ethanol produced from different agricultural feedstocks. In: Int J LCA, Online First, pp., DOI 10.1007/s11367-013-0613-1.
Flury K., Jungbluth N., Frischknecht R. and Muñoz I. (2012) Recommendation for Life Cycle Inventory Analysis for Water Use and Consumption. Working paper by ESU-services Ltd.
Karin Flury, Niels Jungbluth, Rolf Frischknecht: Water Footprint: Methods, State of the Art, Outlook. Presentation for cewas, Willisau, 22. September 2011
Frischknecht R., Jungbluth N. and Pfister S. (2009) UBP-Bewertung für den Wasserbedarf von Treibstoffen.ESU-services, Uster, im Auftrag des Bundesamtes für Umwelt (BAFU), Bern, CH.
