A Multimedia Hydrological Fate Modeling Framework To Assess Water Consumption Impacts in Life Cycle Assessment.

Many new methods have recently been developed to address environmental consequences of water consumption in life cycle assessment (LCA). However, such methods can only partially be compared and combined, because their modeling structure and metrics are inconsistent. Moreover, they focus on specific water sources (e.g., river) and miss description of transport flows between water compartments (e.g., from river to atmosphere via evaporation) and regions (e.g., atmospheric advection). Consequently, they provide a partial regard of the local and global hydrological cycle and derived impacts on the environment. This paper proposes consensus-based guidelines for a harmonized development of the next generation of water consumption LCA indicators, with a focus on consequences of water consumption on ecosystem quality. To include the consideration of the multimedia water fate between compartments of the water cycle, we provide spatial regionalization and temporal specification guidance. The principles and recommendations of the paper are applied to an illustrative case study. The guidelines set the basis of a more accurate, novel way of modeling water consumption impacts in LCA. The environmental relevance of this LCA impact category will improve, yet much research is needed to make the guidelines operational.