Herramienta de gestión continua de actuaciones en seguridad de presas con indicadores de riesgo

[ES] En este documento se presenta una herramienta para la priorización de actuaciones en seguridad de presas a partir de los resultados de un proceso previo de Análisis de Riesgo. Los resultados son analizados a través de indicadores para cada una de las medidas planteadas. Estos indicadores están basados en principios de reducción de riesgo, principalmente de eficiencia y equidad. Con el fin de poder obtener secuencias de implementación de medidas de inversión, se ha desarrollado un software que funciona conjuntamente con un software de cálculo de riesgo y permite obtener secuencias de implementación de medidas de una forma rápida, clara y eficaz a partir de los indicadores de riesgo. Estas secuencias son un apoyo para la toma de decisiones en seguridad de presas. La herramienta desarrollada ha sido aplicada a la gestión de 95 medidas estructurales y no estructurales en un grupo heterogéneo de 27 presas. De esta forma, se han obtenido diferentes secuencias de implementación de medidas para diferentes indicadores de riesgo y se ha analizado como cada una de estas secuencias sigue los diferentes principios de reducción de riesgo.[EN] In this document, a tool for risk reduction measures prioritization in dams¿ security is introduced. This tool is supported by the results of a previous Risk Analysis process. These results are analyzed for each proposed measure using indicators, which are based on risk reduction principles, mainly efficiency and equity. In order to obtain prioritization sequences for risk reduction measures using risk indicators, a software has been developed. This tool is clear, fast and efficient and works jointly with a software for computing risk. The obtained sequences can be a support for decision-making in dam safety. The developed tool has been applied to manage 95 structural and non-structural measures in a heterogeneous group of 27 dams. Different sequences of measures prioritization has been obtained for different risk indicators. The relation between the risk reduction principles and the obtained sequences has been analyzed.Morales Torres, A. (2012). Herramienta de gestión continua de actuaciones en seguridad de presas con indicadores de riesgo. http://hdl.handle.net/10251/27727Archivo delegad

Evaluation of the impact of risk reduction indicators and epistemic uncertainty in dam safety governance

Tesis por compendioLarge dams are critical infrastructures whose failure could produce high economic and social consequences. For this reason, in recent years, the application of quantitative risk analysis to inform dam safety governance has risen significantly worldwide. This thesis is focused in how computed quantitative risk results can be useful to inform dam safety management. It proposes different methods and metrics to deal with the two key issues identified in this process: how risk results can be managed to prioritize potential investments and how uncertainty should be considered in quantitative risk models to inform decision making. Firstly, it is demonstrated that risk reduction indicators are a useful tool to obtain prioritization sequences of potential safety investments, especially in portfolios with a high number of dams. Different indicators for dam safety are assessed, analyzing their relation with equity and efficiency principles. Secondly, it is proposed to consider explicitly and independently natural and epistemic uncertainty in quantitative risk models for dams, following the recommendations developed by other industries. Specifically, a procedure is developed to separate both types of uncertainty in the fragility analysis for the sliding failure mode of gravity dams. Finally, both issues are combined to propose different metrics that analyze the effect of epistemic uncertainty in the prioritization of investments based on risk results. These metrics allow considering the convenience of conducting additional uncertainty reduction actions, like site tests, surveys or more detailed analysis.Las grandes presas son infraestructuras críticas cuyo fallo puede producir importantes consecuencias económicas y sociales. Por este motivo, en los últimos años la aplicación de técnicas de análisis de riesgos para informar a la gobernanza de la seguridad de presas se ha extendido por todo el mundo. La presente tesis se centra en analizar cómo los resultados calculados de riesgo pueden ser útiles para la toma de decisiones en seguridad de presas. Para ello, se proponen diferentes métodos e indicadores que tratan los dos principales problemas identificados en este proceso: cómo gestionar los resultados de riesgo para priorizar potenciales inversiones en seguridad y cómo debe ser considerada la incertidumbre en los modelos de riesgo para orientar a la toma de decisiones. En primer lugar, se muestra como los indicadores de reducción de riesgo son una herramienta útil y eficaz para obtener secuencias de priorización de potenciales medidas de reducción de riesgo, especialmente en la gestión conjunta de grandes grupos de presas. Por ello, los diferentes indicadores para la gestión de la seguridad de presas son evaluados, analizando su relación con los principios de eficiencia y equidad. En segundo lugar, se propone considerar la incertidumbre epistémica y la incertidumbre natural de forma independiente dentro de los modelos de riesgo cuantitativos para presas, siguiendo las recomendaciones de otras industrias. En particular, se propone un procedimiento para separar ambos tipos de incertidumbre en el análisis del modo de fallo por deslizamiento en presas de gravedad. Finalmente, ambos puntos se combinan para proponer diferentes índices que analicen la influencia de la incertidumbre epistémica sobre las secuencias de priorización obtenidas mediante indicadores de reducción de riesgo, y por lo tanto, sobre la toma de decisiones. De esta forma, estos índices permiten analizar la necesidad de realizar acciones adicionales para reducir la incertidumbre epistémica, como ensayos, sondeos o estudios detallados.Les grans preses son infraestructures crítiques que si fallen poden produir importants conseqüències econòmiques i socials. Per aquest motiu, en el últims anys la aplicació de tècniques d'anàlisis de rics per a informar a la governança de seguretat de preses s'ha estès per tot el món. Aquesta tesi es centra en analitzar com els resultats calculats de risc poden ser útils per a prendre decisions en seguretat de preses. Per a això, es proposen diferents mètodes i indicadors que tracten el dos principals problemes identificats en aquest procés: com gestionar els resultats de risc per a prioritzar potencials inversions en seguretat i com el models de risc han de considerar la incertesa per a orientar a la presa de decisions. En primer lloc, es mostra com el indicadors de reducció de riscs son una ferramenta útil i eficaç per a obtindré seqüències de priorització de potencials mesures de reducció de risc, especialment en la gestió conjunta de grans grups de preses. Per això, els diferents indicadors per a la gestió de la seguretat de preses son avaluats, analitzant la seua relació amb els principis d'eficiència i equitat. En segon lloc, es proposa considerar la incertesa natural i la incertesa epistèmica de forma independent dintre del models quantitatius de risc per a preses, seguint les recomanacions d'altres industries. En particular, es proposa un procediment per a separar el dos tipus d'incertesa en el anàlisis del fall per lliscament en preses de gravetat. Finalment, el dos punts es combinen per a proposar índexs que analitzen la influència de la incertesa epistèmica sobre les seqüencies de priorització de mesures obtingudes amb els indicadors de reducció de risc, y per tant, sobre la presa de decisions. D'aquesta forma, aquests índexs permeten analitzar la necessitat de realitzar acciones per a reduir la incertesa, como assajos, sondejos geotècnics o estudis de detall.Morales Torres, A. (2017). Evaluation of the impact of risk reduction indicators and epistemic uncertainty in dam safety governance [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/79739TESISCompendi

Nanotubos e grafeno: os primos mais jovens na família do carbono!

O carbono é o sexto elemento mais abundante do universo, encontrando-se presente tanto na forma orgânica, como em materiais inorgânicos. Além das três formas alotrópicas que ocorrem naturalmente (carbono amorfo, grafite e diamante), podem ser também sintetizadas estruturas de carbono com dimensões nanométricas. Nos últimos anos foram descobertas e caracterizadas novas e interessantes nanoestruturas de carbono, incluindo os nanotubos de carbono e o grafeno. Este breve artigo faz uma resenha sobre os métodos de síntese e caracterização destes dois materiais, aludindo a algumas das suas propriedades mais extraordinárias, bem como às suas aplicações mais recentes e de maior impacto em diversos domínios da ciência e da tecnologia, permitindo, de uma forma simples, introduzir os leitores menos familiarizados com o tema no fascinante mundo destas duas nanoestruturas de carbono

Quantification of climate change impact on dam failure risk under hydrological scenarios: a case study from a Spanish dam

[EN] Dam safety is increasingly subjected to the influence of climate change. Its impacts must be assessed through the integration of the various effects acting on each aspect, considering their interdependencies, rather than just a simple accumulation of separate impacts. This serves as a dam safety management supporting tool to assess the vulnerability of the dam to climate change and to define adaptation strategies under an evolutive dam failure risk management framework. This article presents a comprehensive quantitative assessment of the impacts of climate change on the safety of a Spanish dam under hydrological scenarios, integrating the various projected effects acting on each component of the risk, from the input hydrology to the consequences of the outflow hydrograph. In particular, the results of 21 regional climate models encompassing three Representative Concentration Pathways (RCP2.6, RCP4.5 and RCP8.5) have been used to calculate the risk evolution of the dam until the end of the 21st century. Results show a progressive deterioration of the dam failure risk, for most of the cases contemplated, especially for the RCP2.6 and RCP4.5 scenarios. Moreover, the individual analysis of each risk component shows that the alteration of the expected inflows has the greater influence on the final risk. The approach followed in this paper can serve as a useful guidebook for dam owners and dam safety practitioners in the analysis of other study cases.The authors acknowledge the Spanish Ministry for the Ecological Transition (MITECO) for its support in the preparation of this paper.Fluixá Sanmartín, J.; Morales Torres, A.; Escuder Bueno, I.; Paredes Arquiola, J. (2019). 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Y.: Impact of climate change on hydrological conditions in a tropical West African catchment using an ensemble of climate simulations, Hydrol. Earth Syst. Sci., 21, 2143–2161, https://doi.org/10.5194/hess-21-2143-2017, 2017. 

Empirical Tool for the Assessment of Annual Overtopping Probabilities of Dams

[EN] This paper presents a simple tool for the assessment of maximum overtopping probabilities of dams. The tool is based on empirical relations between the overtopping probability and the basic hydrological and hydraulic characteristics of the dam-reservoir system: the unit storage capacity, VF*, and the unit spillway capacity, QCap*, both weighted with the relative importance of the 1,000-year flood. The surface issued from the tool represents the limit above which no VF*-QCap* combination is statistically expected to offer a higher probability. The tool was calibrated using the detailed overtopping models of 342,233 synthetic cases generated from 30 existing dams and then validated against a set of 21 independent cases. The tool is useful when analyzing a portfolio of dams in previous screening phases of dam risk analysis. It aims at identifying overtopping as a relevant failure mode and easily classifying each dam in terms of its overtopping probability. The tool is also a support for the definition and prioritization of corrective measures since it assesses their impact in the overtopping probability reduction.Fluixá-Sanmartín, J.; Altarejos-García, L.; Morales-Torres, A.; Escuder Bueno, I. (2019). Empirical Tool for the Assessment of Annual Overtopping Probabilities of Dams. Journal of Water Resources Planning and Management. 145(1):1-12. https://doi.org/10.1061/(ASCE)WR.1943-5452.0001017S112145

Accounting for climate change uncertainty in long-term dam risk management

[EN] This paper presents a practical approach to adaptive management of dam risk based on robust decision-making strategies coupled with estimation of climate scenario probabilities. The proposed methodology, called multi-prior weighted scenarios ranking, consists of a series of steps from risk estimation for current and future situations through definition of the consensus sequence of risk reduction measures to be implemented. This represents a supporting tool for dam owners and safety practitioners in making decisions for managing dams or prioritizing long-term investments using a cost-benefit approach. This methodology is applied to the case study of a Spanish dam under the effects of climate change. Several risk reduction measures are proposed and their impacts are analyzed. The application of the methodology allows for identifying the optimal sequence of implementation measures that overcomes uncertainty from the diversity of available climate scenarios by prioritizing measures that reduce future accumulated risks at lower costs. This work proves that such a methodology helps address uncertainty that arises from multiple climate scenarios while adopting a cost-benefit approach that optimizes economic resources in dam risk management.Fluixá-Sanmartín, J.; Escuder Bueno, I.; Morales-Torres, A.; Castillo-Rodríguez, J. (2021). Accounting for climate change uncertainty in long-term dam risk management. Journal of Water Resources Planning and Management. 147(4):1-13. https://doi.org/10.1061/(ASCE)WR.1943-5452.0001355S1131474Amodio, S., D’Ambrosio, A., & Siciliano, R. (2016). Accurate algorithms for identifying the median ranking when dealing with weak and partial rankings under the Kemeny axiomatic approach. 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Safety of Hydropower Dams in a Changing Climate. Journal of Hydrologic Engineering, 19(3), 569-582. doi:10.1061/(asce)he.1943-5584.0000836Choi, O. (2003). Climatic Change, 58(1/2), 149-170. doi:10.1023/a:1023459216609Christensen, J., Kjellström, E., Giorgi, F., Lenderink, G., & Rummukainen, M. (2010). Weight assignment in regional climate models. Climate Research, 44(2-3), 179-194. doi:10.3354/cr00916Danthine, J.-P., & Donaldson, J. B. (2015). Making Choices in Risky Situations. Intermediate Financial Theory, 55-86. doi:10.1016/b978-0-12-386549-6.00003-6Davis, J., Hands, D., & Mäki, U. (1998). The Handbook of Economic Methodology. doi:10.4337/9781781954249Dessai, S., & Hulme, M. (2004). Does climate adaptation policy need probabilities? Climate Policy, 4(2), 107-128. doi:10.1080/14693062.2004.9685515Eggleston H. S. 2006. “National Greenhouse Gas Inventories Programme and Chikyū Kankyō Senryaku Kenkyū Kikan.” In Proc. IPCC guidelines for national greenhouse gas inventories. Geneva: Intergovernmental Panel on Climate Change.Emond, E. J., & Mason, D. W. (2002). A new rank correlation coefficient with application to the consensus ranking problem. Journal of Multi-Criteria Decision Analysis, 11(1), 17-28. doi:10.1002/mcda.313Farnoud Hassanzadeh, F., & Milenkovic, O. (2014). An Axiomatic Approach to Constructing Distances for Rank Comparison and Aggregation. IEEE Transactions on Information Theory, 60(10), 6417-6439. doi:10.1109/tit.2014.2345760Ferson, S., & Ginzburg, L. R. (1996). Different methods are needed to propagate ignorance and variability. Reliability Engineering & System Safety, 54(2-3), 133-144. doi:10.1016/s0951-8320(96)00071-3Fluixá-Sanmartín, J., Altarejos-García, L., Morales-Torres, A., & Escuder-Bueno, I. (2018). Review article: Climate change impacts on dam safety. Natural Hazards and Earth System Sciences, 18(9), 2471-2488. doi:10.5194/nhess-18-2471-2018Fluixá-Sanmartín, J., Escuder-Bueno, I., Morales-Torres, A., & Castillo-Rodríguez, J. T. (2020). Comprehensive decision-making approach for managing time dependent dam risks. Reliability Engineering & System Safety, 203, 107100. doi:10.1016/j.ress.2020.107100Fluixá-Sanmartín, J., Morales-Torres, A., Escuder-Bueno, I., & Paredes-Arquiola, J. (2019). Quantification of climate change impact on dam failure risk under hydrological scenarios: a case study from a Spanish dam. Natural Hazards and Earth System Sciences, 19(10), 2117-2139. doi:10.5194/nhess-19-2117-2019Gersonius, B., Morselt, T., van Nieuwenhuijzen, L., Ashley, R., & Zevenbergen, C. (2012). How the Failure to Account for Flexibility in the Economic Analysis of Flood Risk and Coastal Management Strategies Can Result in Maladaptive Decisions. Journal of Waterway, Port, Coastal, and Ocean Engineering, 138(5), 386-393. doi:10.1061/(asce)ww.1943-5460.0000142Giorgi, F., & Mearns, L. O. (2002). 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Risk and uncertainty in dam safety. doi:10.1680/rauids.32705Harvey, H., Hall, J., & Peppé, R. (2011). Computational decision analysis for flood risk management in an uncertain future. Journal of Hydroinformatics, 14(3), 537-561. doi:10.2166/hydro.2011.055Hawkins, E., & Sutton, R. (2009). The Potential to Narrow Uncertainty in Regional Climate Predictions. Bulletin of the American Meteorological Society, 90(8), 1095-1108. doi:10.1175/2009bams2607.1Heal, G., & Millner, A. (2014). Reflections. Review of Environmental Economics and Policy, 8(1), 120-137. doi:10.1093/reep/ret023Jones, R. N. (2000). Climatic Change, 45(3/4), 403-419. doi:10.1023/a:1005551626280Kaplan, S. (1997). The Words of Risk Analysis. Risk Analysis, 17(4), 407-417. doi:10.1111/j.1539-6924.1997.tb00881.xKENDALL, M. G. (1938). A NEW MEASURE OF RANK CORRELATION. Biometrika, 30(1-2), 81-93. doi:10.1093/biomet/30.1-2.81Khatri, K., & Vairavamoorthy, K. (2011). A New Approach of Decision Making under Uncertainty for Selecting a Robust Strategy: A Case of Water Pipes Failure. Vulnerability, Uncertainty, and Risk. doi:10.1061/41170(400)116Kingston, D. G., Todd, M. C., Taylor, R. G., Thompson, J. R., & Arnell, N. W. (2009). Uncertainty in the estimation of potential evapotranspiration under climate change. Geophysical Research Letters, 36(20). doi:10.1029/2009gl040267Knutti, R., Furrer, R., Tebaldi, C., Cermak, J., & Meehl, G. A. (2010). Challenges in Combining Projections from Multiple Climate Models. Journal of Climate, 23(10), 2739-2758. doi:10.1175/2009jcli3361.1Lempert, R. J., Groves, D. G., Popper, S. W., & Bankes, S. C. (2006). A General, Analytic Method for Generating Robust Strategies and Narrative Scenarios. Management Science, 52(4), 514-528. doi:10.1287/mnsc.1050.0472Lempert, R., Popper, S., & Bankes, S. (2003). Shaping the Next One Hundred Years: New Methods for Quantitative, Long-Term Policy Analysis. doi:10.7249/mr1626Levitan, S., & Thomson, R. (2009). The Application of Expected-Utility Theory to the Choice of Investment Channels in a Defined-Contribution Retirement Fund. ASTIN Bulletin, 39(2), 615-647. doi:10.2143/ast.39.2.2044651Leyva López, J. C., & Alvarez Carrillo, P. A. (2014). Accentuating the rank positions in an agreement index with reference to a consensus order. International Transactions in Operational Research, 22(6), 969-995. doi:10.1111/itor.12146Lind, N. (2007). Discounting risks in the far future. Reliability Engineering & System Safety, 92(10), 1328-1332. doi:10.1016/j.ress.2006.09.001Luo, K., Xu, Y., Zhang, B., & Zhang, H. (2016). Creating an acceptable consensus ranking for group decision making. Journal of Combinatorial Optimization, 36(1), 307-328. doi:10.1007/s10878-016-0086-9Meila M. K. Phadnis A. Patterson and J. A. Bilmes. 2012. “Consensus ranking under the exponential model.” Preprint submitted June 20 2012. http://arxiv.org/abs/1206.5265.Miao, D. Y., Li, Y. P., Huang, G. H., Yang, Z. F., & Li, C. H. (2014). Optimization Model for Planning Regional Water Resource Systems under Uncertainty. Journal of Water Resources Planning and Management, 140(2), 238-249. doi:10.1061/(asce)wr.1943-5452.0000303Minville, M., Brissette, F., & Leconte, R. (2010). Impacts and Uncertainty of Climate Change on Water Resource Management of the Peribonka River System (Canada). Journal of Water Resources Planning and Management, 136(3), 376-385. doi:10.1061/(asce)wr.1943-5452.0000041Morales-Torres, A., Escuder-Bueno, I., Serrano-Lombillo, A., & Castillo Rodríguez, J. T. (2019). Dealing with epistemic uncertainty in risk-informed decision making for dam safety management. Reliability Engineering & System Safety, 191, 106562. doi:10.1016/j.ress.2019.106562Morales-Torres, A., Serrano-Lombillo, A., Escuder-Bueno, I., & Altarejos-García, L. (2016). The suitability of risk reduction indicators to inform dam safety management. Structure and Infrastructure Engineering, 1-12. doi:10.1080/15732479.2015.1136830Neumayer, E., & Barthel, F. (2011). Normalizing economic loss from natural disasters: A global analysis. Global Environmental Change, 21(1), 13-24. doi:10.1016/j.gloenvcha.2010.10.004New, M., & Hulme, M. (2000). Integrated Assessment, 1(3), 203-213. doi:10.1023/a:1019144202120Palmieri, A., Shah, F., & Dinar, A. (2001). Economics of reservoir sedimentation and sustainable management of dams. Journal of Environmental Management, 61(2), 149-163. doi:10.1006/jema.2000.0392Park, T., Kim, C., & Kim, H. (2013). Valuation of Drainage Infrastructure Improvement Under Climate Change Using Real Options. Water Resources Management, 28(2), 445-457. doi:10.1007/s11269-013-0492-zPate-Cornell, E. (2002). Risk and Uncertainty Analysis in Government Safety Decisions. Risk Analysis, 22(3), 633-646. doi:10.1111/0272-4332.00043Pittock, A. B., Jones, R. N., & Mitchell, C. D. (2001). Probabilities will help us plan for climate change. Nature, 413(6853), 249-249. doi:10.1038/35095194Roach, T., Kapelan, Z., Ledbetter, R., & Ledbetter, M. (2016). Comparison of Robust Optimization and Info-Gap Methods for Water Resource Management under Deep Uncertainty. Journal of Water Resources Planning and Management, 142(9), 04016028. doi:10.1061/(asce)wr.1943-5452.0000660Seneviratne, S. I., Corti, T., Davin, E. L., Hirschi, M., Jaeger, E. B., Lehner, I., … Teuling, A. J. (2010). Investigating soil moisture–climate interactions in a changing climate: A review. Earth-Science Reviews, 99(3-4), 125-161. doi:10.1016/j.earscirev.2010.02.004Serrano-Lombillo A. A. Morales-Torres I. Escuder-Bueno and L. Altarejos-García. 2013. “Sharing experience for safe and sustainable water storage.” In Proc. 9th ICOLD European Club Symp. Bergamo Italy: Italian Committee on Large Dams.Spence, C. M., & Brown, C. M. (2018). Decision Analytic Approach to Resolving Divergent Climate Assumptions in Water Resources Planning. Journal of Water Resources Planning and Management, 144(9), 04018054. doi:10.1061/(asce)wr.1943-5452.0000939Street, R. B., & Nilsson, C. (2014). Introduction to the Use of Uncertainties to Inform Adaptation Decisions. Adapting to an Uncertain Climate, 1-16. doi:10.1007/978-3-319-04876-5_1Swart, R. ., Raskin, P., & Robinson, J. (2004). The problem of the future: sustainability science and scenario analysis. Global Environmental Change, 14(2), 137-146. doi:10.1016/j.gloenvcha.2003.10.002Walker, W., Haasnoot, M., & Kwakkel, J. (2013). Adapt or Perish: A Review of Planning Approaches for Adaptation under Deep Uncertainty. Sustainability, 5(3), 955-979. doi:10.3390/su5030955Walker, W. 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A new risk reduction indicator for dam safety management combining efficiency and equity principles

[EN] Large dams are critical infrastructures whose failure could produce high economic and social consequences. Risk analysis has been shown to be a suitable methodology to assess these risks and to inform dam safety management. In this sense, risk reduction indicators are a useful tool to manage risk results, yielding potential prioritisation sequences of investments in dams portfolios. Risk management is usually informed by two basic principles: efficiency and equity. These two principles many times conflict, requiring a tradeoff between optimising the expenditures and providing a high level of protection to all individuals. In this paper, the risk reduction indicator Equity Weighted Adjusted Cost per Statistical Life Saved (EWACSLS) is presented. This indicator allows obtaining prioritisation sequences of investments while maintaining an equilibrium between equity and efficiency principles. In order to demonstrate its usefulness, it has been applied in a real-world case study, a portfolio of 27 dams where 93 structural and non-structural investments are prioritised. The EWACSLS indicator is analysed in detail and its results are compared with other existing risk reduction indicators, showing its flexibility and how it can be a very well balanced indicator for the purpose of prioritisation of risk reduction measures.This paper was published with the support of the research project ‘INICIA’ (Methodology for Assessing Investments on Water Cycle Infrastructures informed on Risk and Energy Efficiency Indicators, BIA2013-48157-C2- 1-R, 2014-2016); co-funded by the Spanish Ministry of Economy and Competitiveness ‘Ministerio de Economía y Competitividad’ (Programa Estatal de Investigación, Desarrollo e Innovación Orientada a los Retos de la Sociedad); and the European Regional Development Fund (ERDF).Serrano Lombillo, AJ.; Morales Torres, A.; Escuder Bueno, I.; Altarejos García, L. (2016). A new risk reduction indicator for dam safety management combining efficiency and equity principles. Structure and Infrastructure Engineering. 13(9):1157-1166. https://doi.org/10.1080/15732479.2016.1245762S11571166139Blackorby, C., & Donaldson, D. (1977). Utility vs equity. Journal of Public Economics, 7(3), 365-381. doi:10.1016/0047-2727(77)90055-xBleichrodt, H. (1997). Health utility indices and equity considerations. Journal of Health Economics, 16(1), 65-91. doi:10.1016/s0167-6296(96)00508-5De Blaeij, A., Florax, R. J. G. ., Rietveld, P., & Verhoef, E. (2003). The value of statistical life in road safety: a meta-analysis. Accident Analysis & Prevention, 35(6), 973-986. doi:10.1016/s0001-4575(02)00105-7(2001). The Economic Journal, 111(471). doi:10.1111/ecoj.2001.111.issue-471Dolan, P. (1998). The measurement of individual utility and social welfare. Journal of Health Economics, 17(1), 39-52. doi:10.1016/s0167-6296(97)00022-2Dundar, H. (1999). Equity, quality and efficiency effects of reform in Turkish higher education. Higher Education Policy, 12(4), 343-366. doi:10.1016/s0952-8733(99)00016-1Jonkman, S. N., van Gelder, P. H. A. J. M., & Vrijling, J. K. (2003). An overview of quantitative risk measures for loss of life and economic damage. Journal of Hazardous Materials, 99(1), 1-30. doi:10.1016/s0304-3894(02)00283-2Joshi, N. N., & Lambert, J. H. (2007). Equity Metrics With Risk, Performance, and Cost Objectives for the Prioritization of Transportation Projects. IEEE Transactions on Engineering Management, 54(3), 539-547. doi:10.1109/tem.2007.900790(1997). Risk Analysis, 17(4). doi:10.1111/risk.1997.17.issue-4Khadam, I. M., & Kaluarachchi, J. J. (2003). Multi-criteria decision analysis with probabilistic risk assessment for the management of contaminated ground water. Environmental Impact Assessment Review, 23(6), 683-721. doi:10.1016/s0195-9255(03)00117-3Linnerooth-Bayer, J., & Amendola, A. (2000). Global Change, Natural Disasters and Loss-sharing: Issues of Efficiency and Equity. Geneva Papers on Risk and Insurance - Issues and Practice, 25(2), 203-219. doi:10.1111/1468-0440.00060(1999). Economic Inquiry, 37(4). doi:10.1111/ecin.1999.37.issue-4Morales-Torres, A., Serrano-Lombillo, A., Escuder-Bueno, I., & Altarejos-García, L. (2016). The suitability of risk reduction indicators to inform dam safety management. Structure and Infrastructure Engineering, 1-12. doi:10.1080/15732479.2015.1136830(2011). Risk Analysis, 31(6). doi:10.1111/risk.2011.31.issue-6Stewart, M. G., & Mueller, J. (2008). A risk and cost-benefit assessment of United States aviation security measures. Journal of Transportation Security, 1(3), 143-159. doi:10.1007/s12198-008-0013-0Yamano, N., & Ohkawara, T. (2000). The Regional Allocation of Public Investment: Efficiency or Equity? Journal of Regional Science, 40(2), 205-229. doi:10.1111/0022-4146.0017

Dealing with epistemic uncertainty in risk-informed decision making for dam safety management

[EN] In recent years, the application of risk analysis to inform dam safety governance has increased significantly. In this framework, considering explicitly and independently both natural and epistemic uncertainty in quantitative risk models allows to understand the sources of uncertainty in risk results and to estimate the effect of actions, tests, and surveys to reduce epistemic uncertainty. In this paper, Indexes of Coincidence are proposed to analyze the effect of epistemic uncertainty in the prioritization of investments based on risk results, which is the key issue in this paper. These indexes allow consideration of the convenience of conducting additional uncertainty reduction actions. These metrics have been applied to the prioritization of risk reduction measures for four concrete gravity dams in Spain. Results allow for a better understanding of how epistemic uncertainty of geotechnical resistance parameters influence risk-informed decision making. The proposed indexes are also useful for probabilistic risk analyses of other civil engineering structures with high epistemic uncertainty environments, since they analyze whether existing uncertainty could have an impact on decision making, outlining the need for extra studies, surveys and tests.Morales Torres, A.; Escuder Bueno, I.; Serrano Lombillo, AJ.; Castillo-Rodríguez, J. (2019). Dealing with epistemic uncertainty in risk-informed decision making for dam safety management. Reliability Engineering & System Safety. 191. https://doi.org/10.1016/j.ress.2019.106562S19

The suitability of risk reduction indicators to inform dam safety management

[EN] Risk analysis can provide very suitable and useful information to manage the safety of critical civil infrastructures. Indeed, results of quantitative risk models can be used to inform prioritisation of safety investments on infrastructures' assets and portfolios. In order to inform this prioritisation, a series of risk reduction indicators can be used. This paper reviews existing indicators for dam safety, tracks how equity and efficiency principles are captured, propose additional indicators and provides insights into how tolerability guidelines and benefit-cost analysis can also play a role in decision-making. All reviewed, analysed and/or combined indicators are later applied in a case study, a portfolio of 27 dams where 93 structural and non-structural investments are prioritised. The case study shows that prioritisation sequences based on risk model results provide suitable and useful information, acknowledging that other concerns may be conditioning decision-making processes. With the results of the case study, a full comparison between all studied risk reduction indicators is made, and three indexes are calculated for all of them to measure how close they are to a theoretical best.The Spanish Ministry of Economy and Competitiveness (MINECO) has supported the work described in this paper through the research project entitled IPRESARA (Incorporating man-made risk components into general dam risk management [BIA 2010-17852]) within the period 2011-2013 and the project INICIA (Methodology for assessing investments on water cycle infrastructures informed on risk and energy efficiency indicators [BIA 2013-48157-C2-1-R]) within the period 2014-2016.Morales Torres, A.; Serrano Lombillo, AJ.; Escuder Bueno, I.; Altarejos García, L. (2016). 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Nanopartículas magnéticas como catalisadores no tratamento de águas utilizando o processo de foto-Fenton

O interesse nas aplicações de nanopartículas magnéticas tem crescido em quase todos os campos, destacando-se mais recentemente a utilização de nanopartículas de óxidos de ferro para tratamento de águas. De entre os óxidos de ferro existentes na natureza, destacam-se o a-Fe2O3, o g-Fe2O3 e o Fe3O4, que podem ser preparados laboratorialmente por métodos de co-precipitação [1], decomposição térmica [2] e síntese hidrotérmica [3]. As nanopartículas superparamagnéticas de óxido de ferro, também conhecidas como SPIONs - superparamagnetic iron oxide nanoparticles, são um caso particular devido à relação entre a distribuição de tamanhos das partículas e a carga superficial. A implementação destes materiais como catalisadores no tratamento de águas e águas residuais pode revolucionar o conceito das tecnologias catalíticas de tratamento porque quando estas nanopartículas, com propriedades magnéticas, são utilizadas em suspensão (i) proporcionam uma maior área de contacto entre a fase ativa e o meio aquoso e (ii) podem ser rapidamente (e facilmente) separadas do meio líquido por efeito de um campo magnético, ficando retidas no reator catalítico. Desta forma são ultrapassadas, tanto a principal limitação encontrada quando são utilizados catalisadores sem propriedades magnéticas em suspensão (difícil separação por processos de filtração), como a limitação associada à deposição de nanopartículas em substratos fixos (típica diminuição da atividade catalítica). Por outro lado, os compostos farmacêuticos são poluentes de maior relevância devido aos efeitos nefastos que podem causar na saúde pública, nos ecossistemas e no ambiente em geral, onde aparecem como resultado do seu consumo crescente e da sua difícil degradação em estações de tratamento de águas residuais. Estes compostos têm sido encontrados em águas subterrâneas, águas de superfície e inclusivamente em águas utilizadas para consumo, sendo esta última uma situação mais alarmante. Em particular, a difenidramina constituí o princípio ativo de diversos produtos farmacêutico, como o Benadryl®, e é classificada como anti-histamínico de primeira geração para formulações farmacêuticas utilizadas no tratamento de rinite, conjuntivite, insónia, picadas de insetos, enjoos/ansiedade, entre outros. Aparece nas águas devido à sua baixa biodegradabilidade e tem demonstrado efeitos tóxicos, cancerígenos e mutagénicos [4]. Por este motivo, no presente trabalho, foram preparados e caracterizados materiais à base de óxido de ferro com propriedades magnéticas para serem testados na degradação de difenidramina pelo processo de foto-Fenton, onde é utilizada uma mistura catalítica fortemente oxidante de um agente contendo ferro e peróxido de hidrogénio (H2O2)