A new water footprint calculation method integrating consumptive and degradative water use into a single stand-alone weighted indicator
- 2.4k Downloads
A complete assessment of water use in life cycle assessment (LCA) involves modelling both consumptive and degradative water use. Due to the range of environmental mechanisms involved, the results are typically reported as a profile of impact category indicator results. However, there is also demand for a single score stand-alone water footprint, analogous to the carbon footprint. To facilitate single score reporting, the critical dilution volume approach has been used to express a degradative emission in terms of a theoretical water volume, sometimes referred to as grey water. This approach has not received widespread acceptance and a new approach is proposed which takes advantage of the complex fate and effects models normally employed in LCA.
Results for both consumptive and degradative water use are expressed in the reference unit H2Oe, enabling summation and reporting as a single stand-alone value. Consumptive water use is assessed taking into consideration the local water stress relative to the global average water stress (0.602). Concerning degradative water use, each emission is modelled separately using the ReCiPe impact assessment methodology, with results subsequently normalised, weighted and converted to the reference unit (H2Oe) by comparison to the global average value for consumptive water use (1.86 × 10−3 ReCiPe points m−3).
Results and discussion
The new method, illustrated in a simplified case study, incorporates best practice in terms of life cycle impact assessment modelling for eutrophication, human and eco-toxicity, and is able to assimilate new developments relating to these and any other impact assessment models relevant to water pollution.
The new method enables a more comprehensive and robust assessment of degradative water use in a single score stand-alone water footprint than has been possible in the past.
KeywordsEnvironmental labelling ReCiPe Water scarcity Water stress Water use Weighting
This study was jointly funded by CSIRO, Australia and ETH Zurich.
- EU-JRC [European Commission-Joint Research Centre — Institute for Environment and Sustainability] (2011) International Reference Life Cycle Data System (ILCD) Handbook—Recommendations for life cycle impact assessment in the European context, 1st edn. Publications Office of the European Union, LuxemburgGoogle Scholar
- Goedkoop M, Spriensma R (2000) The Eco-indicator 99: A damage oriented method for life cycle assessment: Methodology report, 2nd edn. Pré Consultants BV, Amersfoort, The NetherlandsGoogle Scholar
- Goedkoop M, Heijungs R, Huijbregts M, De Schryver A, Struijs J, van Zelm R (2009) ReCiPe 2008: A life cycle impact assessment method which comprises harmonised category indicators at the midpoint and the endpoint level, 1st edn. Ruimte en Milieu, Ministerie van Volkshuisvesting, Ruimtelijke Ordening en Milieubeheer, The NetherlandsGoogle Scholar
- Kounina A, Margni M, Bayart JB, Boulay AM, Berger M, Bulle C, Frischknecht R, Koehler A, Mila-i-Canals L, Motoshita M, Núñez M, Peters G, Pfister S, Ridoutt BG, van Zelm R, Verones F, Humbert S (2011) Review of methods addressing freshwater availability in life cycle inventory and impact assessment. Int J Life Cycle Assess (in revision)Google Scholar
- Masters B, Rohde K, Gurner N, Higham W, Drewry J (2008) Sediment, nutrient and herbicide runoff from canefarming practices in the Mackay Whitsunday region: a field-based rainfall simulation study of management practices. Queensland Department of Natural Resources and Water for the Mackay Whitsunday Natural Resource Management Group, AustraliaGoogle Scholar
- Pfister S, Vionnet S, Humbert S (2012) Ecoinvent 3: assessing water use in LCA and facilitating water footprinting. Int J Life Cycle Assess (in review)Google Scholar
- Ridoutt BG, Poulton PL (2010) Dryland and irrigated cropping systems: comparing the impacts of consumptive water use. In: Notarnicola et al. (eds) Proc VII international conference on life cycle assessment in the agri-food sector. Università degli Studi di Bari Aldo Moro, pp 153–158Google Scholar
- Rockström J, Steffen W, Noone K, Persson Å, Chapin FS, Lambin EF, Lenton TM, Scheffer M, Folke C, Schellnhuber HJ, Nykvist B, de Wit CA, Hughes T, van der Leeuw S, Rodhe H, Sörlin S, Snyder PK, Costanza R, Svedin U, Falkenmark M, Karlberg L, Corell RW, Fabry VJ, Hansen J, Walker B, Liverman D, Richardson K, Cruzen P, Foley JA (2009) A safe operating space for humanity. Nature 461:472–475CrossRefGoogle Scholar