Robust estimates of climate-induced hydrological change in a temperate mountainous region

A sustainable water resources management depends on sound information about the impacts of climate change. This information is, however, not easily derived because natural runoff variability interferes with the climate change signal. This study presents a procedure that leads to robust estimates of magnitude and Time Of Emergence (TOE) of climate-induced hydrological change that also account for the natural variability contained in the time series. Firstly, natural variability of 189 mesoscale catchments in Switzerland is sampled for 10 ENSEMBLES scenarios for the control (1984-2005) and two scenario periods (near future: 2025-2046, far future: 2074-2095) applying a bootstrap procedure. Then, the sampling distributions of mean monthly runoff are tested for significant differences with the Wilcoxon-Mann-Whitney test and for effect size with Cliff's delta d. Finally, the TOE of a climate change induced hydrological change is determined when at least eight out of the ten hydrological projections significantly differ from natural variability. The results show that the TOE occurs in the near future period except for high-elevated catchments in late summer. The significant hydrological projections in the near future correspond, however, to only minor runoff changes. In the far future, hydrological change is statistically significant and runoff changes are substantial. Temperature change is the most important factor determining hydrological change in this mountainous region. Therefore, hydrological change depends strongly on a catchment's mean elevation. Considering that the hydrological changes are predicted to be robust in the near future highlights the importance of accounting for these changes in water resources planning

In light of seasonal climatic and anthropogenic changes, is the Vaud Canton (Switzerland) vulnerable to water stress by the medium-term?

Observed changes in hydrological processes during the past 20 years in Switzerland are particularly preoccupying as they directly affect water use. In 2003 and 2011, local water shortage episodes occurred. Water withdrawals and supplies had to be restricted, notably in the canton of Vaud (Western Switzerland). These droughts highlighted increasing competition among water users and new water management issues arose. This study explores how hydro-climatic conditions and water needs could evolve by the 2060 horizon and assesses the vulnerability of the canton to water stress under climatic and anthropogenic changes. A daily semi-distributed hydrological model was used to simulate flows. Future changes were derived from Swiss climate scenarios relying on ten regional climate models. Regarding water needs, a population growth scenario was provided by the canton whereas a business-as-usual scenario was considered for irrigation and breeding trends. Currently, catchments in the canton experience moderate water stress from June to August, except in alpine areas. By the medium-term, water needs could reach more than 80% of rivers' total runoff in July and August. This should be due to higher temperatures and a higher ratio of liquid-to-solid precipitation causing more severe low flows. In addition, water needs should significantly increase from April to July, due to higher irrigation (+25%) and urban (+40%) water needs. This study gives a first overview of where and when water tensions are most likely to occur in the canton of Vaud. Highlighting these regional differences supports the development of strategies to cope with water stress that are currently being discussed with the cantonal authorities

Climatic and anthropogenic changes in Western Switzerland: Impacts on water stress

Recent observed hydro-climatic changes in mountainous areas are preoccupying as they may directly affect the capacity to fulfill water needs. The canton of Vaud is representative of this context as it underwent local water shortage episodes during the past decade. Based on an integrated modeling framework, this study explores how hydro-climatic conditions and water needs could evolve in mountain environments and assesses their potential impacts on water stress by the 2060 horizon. Flows were simulated based on a daily semi-distributed hydrological model. Future changes were derived from Swiss climate scenarios based on two regional climate models. Regarding water needs, the authorities of the canton of Vaud provided a population growth scenario while irrigation and breeding trends followed a business-as-usual scenario. Currently, the canton of Vaud experiences moderate water stress from June to August, except in its alpine area where no stress is noted. In the 2060 horizon, water needs could exceed 80% of the rivers' available resources in low- to mid- altitude environments in mid-summer. This should be due to the combination of drier and warmer climate enhancing longer and more severe low flows, and increasing urban (+40%) and irrigation (+25%) water needs. Highlighting regional differences supports the development of sustainable development pathways to reduce water tensions. Based on a quantitative assessment, this study also calls for broader impact studies including water quality issues

Towards e-passport duplicate enrollment check in the European Union

Automated border control gates are now being more and more deployed at airports to smooth border crossings with reduced man power and more convenience to the passenger. In order to use these new gates the traveler is required to present an electronic passport (e-Passport or biometric passport). Lots of efforts have been undertaken to improve the security of the infrastructure at borders or by adding various security features to the passport. However, the weakest point in the passport issuance process is the enrolment step for passport applicant including the breeder documents authenticity and the duplicate enrolment check. The goal of duplicate enrolment check is to prevent the issuance of duplicate illegal passports containing possibly fake identities. A solution to this problem needs to be flexible and precise if the solution is meant for large-scale deployments and eventually standardization. This paper describes how a duplicate enrolment check can be realized securely between European Union member states using distributed databases of alphanumeric data and multiple biometric modalities

Robust estimates of climate-induced hydrological change in a temperate mountainous region

A sustainable water resources management depends on sound information about the impacts of climate change. This information is, however, not easily derived because natural runoff variability interferes with the climate change signal. This study presents a procedure that leads to robust estimates of magnitude and Time Of Emergence (TOE) of climate-induced hydrological change that also account for the natural variability contained in the time series. Firstly, natural variability of 189 mesoscale catchments in Switzerland is sampled for 10 ENSEMBLES scenarios for the control (1984–2005) and two scenario periods (near future: 2025–2046, far future: 2074–2095) applying a bootstrap procedure. Then, the sampling distributions of mean monthly runoff are tested for significant differences with the Wilcoxon-Mann–Whitney test and for effect size with Cliff’s delta d. Finally, the TOE of a climate change induced hydrological change is determined when at least eight out of the ten hydrological projections significantly differ from natural variability. The results show that the TOE occurs in the near future period except for high-elevated catchments in late summer. The significant hydrological projections in the near future correspond, however, to only minor runoff changes. In the far future, hydrological change is statistically significant and runoff changes are substantial. Temperature change is the most important factor determining hydrological change in this mountainous region. Therefore, hydrological change depends strongly on a catchment’s mean elevation. Considering that the hydrological changes are predicted to be robust in the near future highlights the importance of accounting for these changes in water resources planning