Search

Purpose: The Peruvian coast is known for its low water availability and high water demand, which is mainly satisfied by groundwater sources. The current study develops regionalized water scarcity characterization factors (CFs) based on the available water remaining (AWARE) method for eight selected watersheds located along the hyper-arid Peruvian coast. Furthermore, the paper proposes water scarcity CFs for groundwater in six watersheds, which are not available in current methods. Methods: The regionalization of water scarcity CFs along the Peruvian coast was based on the following: (i) national delineation of hydrological units (HUs), (b) use of primary data on water availability and demand provided by official water balance reports and national databases, (c) use of the ecological flow values recommended by national authorities, and (d) proposal of specific water scarcity CFs for groundwater. Moreover, the results of the updated CFs were compared to those from the original CFs from AWARE. A sensitivity analysis, including recalculated CFs based on future climate change scenarios, was also provided. Thereafter, water scarcity impacts for grape and avocado production available in the scientific literature were recalculated based on previous studies with the new CFs. Results and discussion: Results revealed significant differences between updated and original water scarcity CFs in both geographical and temporal (i.e., monthly) terms. Hence, updated CFs showed that all watersheds selected experience high levels of water scarcity, especially from June to October, a more realistic scenario than that showed with original water scarcity CFs when confronted to water availability values. Meanwhile, water scarcity CFs for groundwater showed intense pressure all year round for the three main sources of groundwater (i.e., Chillon, Rimac, and Lurin aquifers) that provide water to the city of Lima, whereas only one groundwater watershed showed low water scarcity (i.e., Mala-Omas aquifer). Conclusions: Updated water scarcity CFs provide a watershed-based quantification of water scarcity in the hyper-arid Peruvian coast, which we consider more realistic as compared to the original CFs. Moreover, the water scarcity CFs proposed for groundwater allow estimating the pressure over aquifers in a higher level of disaggregation, which can be used to monitor the overexploitation of groundwater sources in an area that is highly dependent on these water sources. [ABSTRACT FROM AUTHOR]

Purpose: This paper presents the regionalized water scarcity characterization factors (CFs) of the available water remaining (AWARE) model, which was found by a previous study, on the water scarcity in Brazil, to be the most indicative characterization model for the water-scarce regions in Brazil. We used the national database and hydrographic delimitations defined by the National Water Agency (Agência Nacional de Águas — ANA) to generate the regionalized AWARE BR CFs. Methods: The CFs were regionalized by hydrographic delimitations used by ANA: (i) State Hydrographic Units (SHU) and (ii) Hydrographic Regions (HR). These AWARE BR CFs were compared with the factors originally proposed by WULCA (2018) and with the Scarcity Index used by ANA to identify the scarcest regions in the country. Finally, the AWARE and AWARE BR factors were applied to a case study of Brazilian melons, evaluating the regionalization effects on the results of water scarcity analysis. Results and discussion: The AWARE BR CFs demonstrate most consistency with the regions recognized by ANA to have water scarcity problems, such as the semiarid region. Approximately 12% of the SHUs exhibited maximum water scarcity (CF = 100) during the entire year, while 11% presented minimum scarcity factors (CF = 0.1). The comparison of hydrologic data from ANA with those from WaterGAP indicated that water availability was overestimated in WaterGAP, while demand was underestimated in different basins. The comparison of AWARE BR CFs with ANA Scarcity Index values indicated more similarity (smaller residual error) than the comparison of AWARE BR CFs with AWARE. The case study regarding the impact of water scarcity on melons showed a significant difference between characterization factors and, consequently, in the values of impact. Conclusions: AWARE BR factors generated with national characterization data are adapted to the different regions of Brazil, exhibiting higher sensitivity to the semiarid region. This regionalization provided a more accurate representation of the scarcity in smaller basins located in larger basins, characterized by large climate variation. [ABSTRACT FROM AUTHOR]

Purpose: Weighting can enable valuable support for decision-makers when interpreting life cycle assessment (LCA) results. Distance-to-target (DtT) weighting is based on the distance of policy (desired) targets to current environmental situations, and recent methodological DtT developments are based on a weighting perspective of a single region or country, considering mainly environmental situations in consuming countries or regions. However, as product supply chains are spread over many countries, this study aims at developing additional weighting approaches (producer regions and worst-case regions) and applying them in a theoretical case study on a global scale. Methods: The current study is carried out to understand the influence of and the effect on weighting results of different countries and regions with their specific environmental policy targets. Based on the existing Ecological Scarcity Method (ESM), eco-factors for the three environmental issues climate change, acidification, and water resources were derived for as many countries as possible. The regional eco-factors were applied in a case study for steel and aluminum considering the three different weighting approaches on different regional scales. Results and discussion: The analysis revealed significant differences in the obtained weighting results as well as strengths and limitations in the applicability of the examined perspectives. Acidification was showed to be highly important with between 80 and 92% of the aggregated weighting results among the perspectives where water-scarce countries were not involved. Water-scarce countries had a significant influence (75–95%) when they were part of the examined case study. Conclusions: The developed approaches enable the assessment of global value chains in different producer regions as well as the utilization of the conservative worst-case-regions approach. The approaches can foster future decision-making in LCA contexts while providing country-specific results based on different weighting perspectives in national, regional, and global contexts. However, for a complete implementation of the presented approaches, further data gathering is needed on environmental situations and policy targets in different countries as well as regionalized life cycle data. [ABSTRACT FROM AUTHOR]

Purpose: Regionalised characterisation factors (CFs) for watersheds around the world are available to assess water use-related environmental impacts. The main problem with using the watershed regionalisation level arises when a single CF is generated for large watersheds in countries where water availability and demand are not uniform. Additionally, water availability and use vary over time because of the effects of climate change and changing human lifestyles. These two factors are currently not taken into account in CFs, but should be included for the sake of the accuracy of LCA results. The aim of this research was to provide water stress index CFs at the sub-watershed spatial level for three temporal scenarios (present, short-term future and mid-term future) for Spain (Southern Europe), a country with considerable variability in water availability that is especially vulnerable to climate change effects. Methods: CFs were calculated following the water stress index (WSI) definition of Pfister et al. (Environ Sci Technol 43(11):4098-4104, ). The WSI was calculated on a yearly basis for 117 sub-watersheds-compared to 56 regionalisation units provided in the original method-and for (i) the current situation: current water use and availability; (ii) short-term future: projections for 2015; and (iii) mid-term future: projections for 2030. The uncertainties of the CFs were calculated for each sub-watershed. Results and discussion: Temporal trend analysis of the CFs showed a general relaxation of water stress over the short-term when compared to the current situation, followed by a new increase. Major differences were noticed in the WSIs calculated by Pfister et al. (Environ Sci Technol 43(11):4098-4104, ) using global data and maps and the WSIs calculated in this study using national and regional data. The WSIs under consideration of uncertainty were higher than the deterministic result for intermediate WSIs. Conclusions: The CFs generated are useful compared with the CFs previously available because they improve evaluation of the water use-related impacts of present and future technologies with the life cycle stages located in Spain. We encourage LCA developers to update WSIs for other countries using information at the national level that is usually freely accessible. [ABSTRACT FROM AUTHOR]