Estimation of high return period flood quantiles using additional non-systematic information with upper bounded statistical models

This paper proposes the estimation of high return period quantiles using upper bounded distribution functions with Systematic and additional Non-Systematic information. The aim of the developed methodology is to reduce the estimation uncertainty of these quantiles, assuming the upper bound parameter of these distribution functions as a statistical estimator of the Probable Maximum Flood (PMF). Three upper bounded distribution functions, firstly used in Hydrology in the 90's (referred to in this work as TDF, LN4 and EV4), were applied at the Jucar River in Spain. Different methods to estimate the upper limit of these distribution functions have been merged with the Maximum Likelihood (ML) method. Results show that it is possible to obtain a statistical estimate of the PMF value and to establish its associated uncertainty. The behaviour for high return period quantiles is different for the three evaluated distributions and, for the case study, the EV4 gave better descriptive results. With enough information, the associated estimation uncertainty for very high return period quantiles is considered acceptable, even for the PMF estimate. From the robustness analysis, the EV4 distribution function appears to be more robust than the GEV and TCEV unbounded distribution functions in a typical Mediterranean river and Non-Systematic information availability scenario. In this scenario and if there is an upper limit, the GEV quantile estimates are clearly unacceptable

Assessing the risk of vehicle instability due to flooding

[EN] Flooding can destabilize vehicles which might, in turn, exacerbate the negative effects of floods when vehicles are swept away by flows, and lead to economic loss and fatalities. In order to suitably manage floods, it is necessary to determine the risk of instability to which vehicles in flood-prone areas are subject. This paper develops a methodology to estimate this risk based on the characteristics of floods and the vehicle fleet located in potential flood-prone areas. This risk is determined by the statistical integral of the instability hazard and vehicles' vulnerability. The instability hazard was established by a stability function of partially submerged cars and flood frequency, while vulnerability was calculated by combining the susceptibility and exposure of cars. Our methodology was applied in the towns of Alfafar and Massanassa (Spain). It found that the annualized instability risk due to flooding could be relatively high on most streets and roads, with values reaching the order of 8.4 at-risk vehicles per hectare/year.Departamento Administrativo de Ciencia, Tecnologia e Innovacion COLCIENCIAS (Colombia) call, Grant/Award Number: 728-2015; Spanish Ministry of Science and Innovation through the research project TETISCHANGE, Grant/Award Number: RTI2018-093717-B-I00Bocanegra, RA.; Francés, F. (2021). Assessing the risk of vehicle instability due to flooding. Journal of Flood Risk Management. 14(4):1-15. https://doi.org/10.1111/jfr3.12738S11514

Caracterização hidrogeológica e avaliação da vulnerabilidade à poluição agrícola do aquífero Mio-Pliocénico da região de Canhestros, Alentejo

O bloco de rega de Canhestros, ocupa uma extensão de 100 km2 e integra-se na 2ª Fase do Perímetro de Rega da Barragem de Odivelas, tendo sido a primeira estrutura do vasto sistema hidráulico baseado na Barragem do Alqueva, a entrar em funcionamento, em Fevereiro de 2002. No âmbito de um projecto de monitorização piezométrica e de qualidade da água subterrânea para a referida área, celebrado entre o IGM e a EDIA, tem sido realizadas periodicamente amostragens à composição físico-química da água subterrânea, incluindo compostos orgânicos de alguns pesticidas e nitratos, que constituem elementos indicadores de contaminação agrícola. A avaliação das condições hidrogeológicas e da vulnerabilidade à poluição dos sistemas aquíferos em áreas de agricultura intensiva reveste-se da maior importância para a definição da situação de referência dos aspectos hidrodinâmicos e de qualidade da água, numa fase anterior aos previsíveis impactes que as alterações do uso do solo e o incremento do regadio inevitavelmente irão provocar. O sistema hidrogeológico dominante na área de estudo corresponde à Formação de Esbarrondadoiro (Miocénico), de fácies detrítica, e aos depósitos Plio-Quaternários de cobertura. É possível identificar-se um aquífero superficial poroso livre e em profundidade vários níveis aquíferos confinados, constituindo no conjunto um sistema multicamada complexo, em que o aquífero superficial se apresenta mais vulnerável à contaminação pontual e difusa de origem agrícola. De acordo com diferentes metodologias empíricas e critérios hidrogeológicos a área do Perímetro de Rega de Canhestros, classifica-se, relativamente ao aquífero superficial, como área de vulnerabilidade média a extremamente elevada à poluição agrícola (ver tabela). Em face dos resultados preliminares do trabalho de campo não é aconselhável o uso agrícola das águas subterrâneas da área do Perímetro de Rega de Canhestros pelo elevado risco de salinização dos solos, potenciado pelo clima quente e seco da região. Não foram detectados valores significativos de fitofármacos no aquífero livre (ver tabela) e os teores em nitratos são normalmente inferiores a 25 mg/L, à excepção de alguns casos pontuais sem representatividade espacial (ver tabela). Os resultados obtidos com os trabalhos em curso, sob a forma de diagramas, índices hidrogeoquímicos e mapas de isovalores, serão posteriormente integradas em Bases de Dados/SIG constituindo instrumentos de gestão ambiental importantes na definição das futuras redes de monitorização, a implementar no final do projecto

Digital homotopy with obstacles

AbstractIn (Ayala et al. (Discrete Appl. Math. 125 (1) (2003) 3) it was introduced the notion of a digital fundamental group π1d(O/S;σ) for a set of pixels O in relation to another set S which plays the role of an “obstacle”. This notion intends to be a generalization of the digital fundamental groups of both digital objects and their complements in a digital space. However, the suitability of this group was only checked for digital objects in that paper. As a sequel, we extend here the results in Ayala et al. (2003) for complements of objects. More precisely, we prove that for arbitrary digital spaces the group π1d(O/S;σ) maps onto the usual fundamental group of the difference of continuous analogues |AO∪S|−|AS|. Moreover, this epimorphism turns to be an isomorphism for a large class of digital spaces including most of the examples in digital topology

Review and analysis of vehicle stability models during floods and proposal for future improvements

This is the peer reviewed version of the following article: Bocanegra, RA, Vallés-Morán, FJ, Francés, F. Review and analysis of vehicle stability models during floods and proposal for future improvements. J Flood Risk Management. 2020; 13 ( Suppl. 1):e12551, which has been published in final form at https://doi.org/10.1111/jfr3.12551. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.[EN] Flood water can affect vehicles significantly, which in turn can increase the negative effects of floods as vehicles are washed away by the flow and become a form of debris. In cities, most fatalities during floods occur inside vehicles. Consequently, it is necessary to establish thresholds for vehicle stability during this type of event to provide information necessary for flood risk management. This article analyses the available stability models developed over recent years to determine such thresholds. The stability models were grouped according to the way in which they approached car watertightness and the stability thresholds proposed by each of them were compared. It was found that these thresholds vary over a relatively wide range. Additionally, the experimental data were compared with the results provided by these studies leading to the conclusion that several of the stability models analysed do not fit measured data well. New research is required to overcome the simplifications made by the state-of-the-art models and to try to standardise the decision criteria which should be adopted to define stability thresholds for vehicles of different characteristics.Departamento Administrativo de Ciencia, Tecnologia e Innovacion COLCIENCIAS (Colombia) call 728-2015; Spanish Ministry of Science and Innovation through the research project TETISCHANGE, Grant/Award Number: RTI2018-093717-B-I00.Bocanegra, RA.; Vallés-Morán, FJ.; Francés, F. (2020). Review and analysis of vehicle stability models during floods and proposal for future improvements. Journal of Flood Risk Management. 13:1-13. https://doi.org/10.1111/jfr3.12551S11313Arrighi, C., Alcèrreca-Huerta, J. C., Oumeraci, H., & Castelli, F. (2015). Drag and lift contribution to the incipient motion of partly submerged flooded vehicles. Journal of Fluids and Structures, 57, 170-184. doi:10.1016/j.jfluidstructs.2015.06.010Arrighi C. Castelli F. &Oumeraci H.(2016). Effects of flow orientation on the onset of motion of flooded vehicles. InProceedings of the 4th IAHR Europe Congress. Liege DOI:https://doi.org/10.1201/b21902-140.Arrighi, C., Huybrechts, N., Ouahsine, A., Chassé, P., Oumeraci, H., & Castelli, F. (2016). Vehicles instability criteria for flood risk assessment of a street network. Proceedings of the International Association of Hydrological Sciences, 373, 143-146. doi:10.5194/piahs-373-143-2016Bonham A. J. &Hattersley R. T.(1967).Low level causeways. WRL Report No. 100. University of New South Wales. Sydney Australia.Cox R. J. Shand T. D. &Blacka M. J.(2010). Appropriate safety criteria for people in floods.Australian Rainfall and Runoff. WRL Research Report 240. Report for Institution of Engineers Australia.DROBOT, S., BENIGHT, C., & GRUNTFEST, E. (2007). Risk factors for driving into flooded roads. Environmental Hazards, 7(3), 227-234. doi:10.1016/j.envhaz.2007.07.003FitzGerald, G., Du, W., Jamal, A., Clark, M., & Hou, X.-Y. (2010). Flood fatalities in contemporary Australia (1997-2008). Emergency Medicine Australasia, 22(2), 180-186. doi:10.1111/j.1742-6723.2010.01284.xGordon A. D. &Stone P. B.(1973).Car stability on road causeways. WRL Technical Report No. 73/12. University of New South Wales. Sydney Australia.Jonkman, S. N., & Kelman, I. (2005). An Analysis of the Causes and Circumstances of Flood Disaster Deaths. Disasters, 29(1), 75-97. doi:10.1111/j.0361-3666.2005.00275.xKellar, D. M. M., & Schmidlin, T. W. (2012). Vehicle-related flood deaths in the United States, 1995-2005. Journal of Flood Risk Management, 5(2), 153-163. doi:10.1111/j.1753-318x.2012.01136.xKeller R. J. &Mitsch B.(1993).Safety aspects of the design of roadways as floodways. Research Report No. 69 Urban Water Research Association of Australia.Kramer, M., Terheiden, K., & Wieprecht, S. (2016). Safety criteria for the trafficability of inundated roads in urban floodings. International Journal of Disaster Risk Reduction, 17, 77-84. doi:10.1016/j.ijdrr.2016.04.003Martínez-Gomariz, E., Gómez, M., Russo, B., & Djordjević, S. (2016). Stability criteria for flooded vehicles: a state-of-the-art review. Journal of Flood Risk Management, 11, S817-S826. doi:10.1111/jfr3.12262Martínez-Gomariz, E., Gómez, M., Russo, B., & Djordjević, S. (2017). A new experiments-based methodology to define the stability threshold for any vehicle exposed to flooding. Urban Water Journal, 14(9), 930-939. doi:10.1080/1573062x.2017.1301501Mens M. J. Erlich M. Gaume E. Lumbroso D. Moreda Y. Van der VatM. &Versini P. A.(2008).Frameworks for flood event management. Report Number T19‐07‐03. WL Delft Hydraulics. Delft Netherlands.Moore, K. A., & Power, R. K. (2002). Safe Buffer Distances for Offstream Earth Dams. Australasian Journal of Water Resources, 6(1), 1-15. doi:10.1080/13241583.2002.11465206Oshikawa H. &Komatsu T.(2014). Study on the risk evaluation for a vehicular traffic in a flood situation.Proceedings of the 19th IAHR‐APD Congress Hanoi Vietnam.Pregnolato, M., Ford, A., Wilkinson, S. M., & Dawson, R. J. (2017). The impact of flooding on road transport: A depth-disruption function. Transportation Research Part D: Transport and Environment, 55, 67-81. doi:10.1016/j.trd.2017.06.020Shand T. Cox R. Blacka M. &Smith G.(2011).Australian Rainfall and Runoff (AR&R). Appropriate safety criteria for vehicles. Australian rainfall and runoff revision project 10: Report Number: P10/S2/020. Sidney Australia.Shu, C., Xia, J., Falconer, R. A., & Lin, B. (2011). Incipient velocity for partially submerged vehicles in floodwaters. Journal of Hydraulic Research, 49(6), 709-717. doi:10.1080/00221686.2011.616318Smith G. P. Davey E. K. &Cox R. J.(2014).Flood hazard. WRL Technical Report 2014/07. University of New South Wales. Sydney Australia.Smith G. P. Modra B. D. Tucker T. A. &Cox R. J.(2017).Vehicle stability testing for flood flows. WRL Technical Report 2017/07. University of New South Wales. Sydney Australia.Suarez, P., Anderson, W., Mahal, V., & Lakshmanan, T. R. (2005). Impacts of flooding and climate change on urban transportation: A systemwide performance assessment of the Boston Metro Area. Transportation Research Part D: Transport and Environment, 10(3), 231-244. doi:10.1016/j.trd.2005.04.007Teo, F. Y., Xia, J., Falconer, R. A., & Lin, B. (2012). Experimental studies on the interaction between vehicles and floodplain flows. International Journal of River Basin Management, 10(2), 149-160. doi:10.1080/15715124.2012.674040Versini, P.-A., Gaume, E., & Andrieu, H. (2010). Application of a distributed hydrological model to the design of a road inundation warning system for flash flood prone areas. Natural Hazards and Earth System Sciences, 10(4), 805-817. doi:10.5194/nhess-10-805-2010Versini, P.-A., Gaume, E., & Andrieu, H. (2010). Assessment of the susceptibility of roads to flooding based on geographical information – test in a flash flood prone area (the Gard region, France). Natural Hazards and Earth System Sciences, 10(4), 793-803. doi:10.5194/nhess-10-793-2010Xia, J., Falconer, R. A., Xiao, X., & Wang, Y. (2013). Criterion of vehicle stability in floodwaters based on theoretical and experimental studies. Natural Hazards, 70(2), 1619-1630. doi:10.1007/s11069-013-0889-2Xia, J., Teo, F. Y., Lin, B., & Falconer, R. A. (2010). Formula of incipient velocity for flooded vehicles. Natural Hazards, 58(1), 1-14. doi:10.1007/s11069-010-9639-

Variables de influencia en la productividad de biomasa de matorral en la mancomunidad de El Alto Jarama-Atazar

La situación energética actual, caracterizada por la búsqueda de nuevas fuentes de energía, sustitutivas de los combustibles fósiles tradicionales y menos agresivas con el medio ambiente, ha hecho necesaria la puesta en marcha de políticas y acuerdos a nivel mundial, que buscan reducir la contaminación y fomentar las energías renovables. La biomasa, recurso renovable perteneciente a cada país y con un poder calorífico suficientemente alto como para emplearse energéticamente, surge como alternativa a dichos combustibles fósiles. Estos aspectos han convertido el estudio del potencial biomásico de los montes en uno de los pasos previos imprescindibles para cualquier proyecto vinculado al desarrollo de las bioenergías. Sin embargo, la evaluación de la biomasa encierra numerosas dificultades, dado que como recurso vegetal y renovable que es, presenta un carácter variable, cualitativa y cuantitativamente. Este factor, junto a la complejidad de estimar el potencial biomásico de grandes extensiones, provoca que únicamente se calcule la biomasa arbórea, en detrimento de la arbustiva, proporcionando un valor generalmente más bajo del realmente disponible en cada zona. Este estudio establece una metodología más precisa para el cálculo de la biomasa potencial generada por el matorral, en una determinada zona de estudio (Mancomunidad de El Alto Jarama-Atazar).____________________________________The present situation in the energy field is mainly characterized by the constant search of new energy sources, traditional fossil fuel substitutive and less aggressive towards the environment. All this has favoured the implementation of policies and worldwide agreements to reduce pollution and to promote Renewable Energies. The Biomass, a renewable resource belonging to each country and with a sufficiently high heating value to use energetically, arises as an alternative to the above mentioned fossil fuels. These aspects have turned the study of the forestry biomass resources into one of the previous essential steps of any project related to the development of Bioenergy. However, Biomass quantifying has numerous difficulties given that as vegetable and as renewable resource, it presents a changeable character, both qualitatively and quantitatively. In addition the impossibility to estimate the Biomass potential in large extensions causes that only arboreal biomass to be calculated, to the detriment of the bush tree, and therefore, generally the estimation provides a value that is minor than the real one. This study tries to establish a more accurate methodology for the calculation of the potential Biomass generated by the thickets in a specific study zone (Mancomunidad de El Alto Jarama-Atazar)

Aplicação de um SIG na selecção de locais para implantação de aterros sanitários em áreas vulneráveis à contaminação de aquíferos

No âmbito de um estágio profissionalizante da licenciatura de Engenharia do Ambiente foi desenvolvida e testada uma metodologia para a selecção de possíveis locais de implantação de aterros sanitários, recorrendo aos sistemas de informação geográfica. A localização deste tipo de infra-estruturas obedece a critérios diversos de natureza geológica, geomorfológica, topográfica, pedológica, biológica, hídrica, hidrogeológica, climatológica, demográfica, usos de solo e acessibilidades. O armazenamento, a integração e a manipulação de toda a informação de base foi possível graças ao desenvolvimento de um SIG, que permitiu igualmente a produção de informação intermédia e a geração do output final de acordo com os critérios exigidos. Para o efeito foi seleccionada uma área de 640 km2 no nordeste alentejano, tendo sido testadas as respostas dadas por este método em locais vulneráveis à contaminação de aquíferos. As áreas geradas pelo Sistema foram validadas no campo verificando-se estarem em conformidade com os condicionalismos introduzidos no sistema. A metodologia que se coloca à discussão tem como objectivo evidenciar as potencialidades dos SIG em análises de macroescala, no contexto do planeamento e do ordenamento do território, em consonância com a gestão de recursos hídricos

Climate fluctuations during the Holocene in NW Iberia: high and low latitude linkages

International audienceHigh resolution benthic foraminiferal oxygen and carbon stable isotopes (?18O, ?13C) from core EUGC-3B are used here to infer rapid climatic changes for the last 8500 yr in the Ría de Muros (NW Iberian Margin). Benthic foraminiferal ?18O and ?13C potentially register migrations in the position of the hydrographic front formed between two different intermediate water masses: Eastern North Atlantic Central Water of subpolar origin (ENACWsp), and subtropical origin (ENACWsp). The isotopic records have been compared with two well established North Atlantic marine Holocene paleoceanographic records from low (Sea Surface Temperatures anomalies off Cape Blanc, NW Africa) and high latitudes (Hematite Stained Grains percentage, subpolar North Atlantic). This comparison clearly demonstrates that there is a strong link between high- and low-latitude climatic perturbations at centennial-millennial time scales during the Holocene. Spectral analyses also points at a pole-to-equator propagation of the so-called 1500 yr cycles. Our results demonstrate that during the Holocene, the NW Iberian Margin has undergone a series of cold episodes which are likely triggered at high latitudes in the North Atlantic and are rapidly propagated towards lower latitudes. Conceivably, the propagation of these rapid climatic changes involves a shift of atmospheric and oceanic circulatory systems and so a migration of the hydrographical fronts and water masses all along the North Atlantic area

Influencia de los materiales triásicos en la calidad del agua de algunos acuíferos kársticos del sur de Alicante (España)

Overexploitation of the aquifers of the Middle Vinalopó (SE Spain) has led to problems which, in many cases, are associated with groundwater salinization. The increase in salinity is considered to be due to the dissolution of mineral salts in the Triassic Keuper facies. Geophysical logging of various boreholes in three aquifers in this region confirms the presence of more mineralized waters at depth. The evidence suggests that the phenomenon of salinization results from mixing of these deep waters with more shallow ones. The fall in the ratio of freshwater to saltwater as overexploitation continues and the aquifer is emptied could explain the increased mineralization that has been observed at many boreholes that penetrate these aquifers.La fuerte presión sometida a los acuíferos del Medio Vinalopó (SE España) ha originado problemas de sobreexplotación, los cuales van asociados en un gran número de casos a la salinización del agua. El aumento de salinidad ha sido interpretado como debido a la disolución de sales provenientes de los materiales triásicos del Keuper. La testificación geofísica de diversos sondeos de tres acuíferos de esta región ha permitido constatar la presencia de aguas más mineralizadas en profundidad. Por tanto, todo indica que el fenómeno de la salinización se debe a la mezcla del agua más superficial con la profunda. La disminución de la relación agua dulce-agua salada, a medida que progresa la sobreexplotación y el vaciado del acuífero, podría explicar el aumento de la mineralización que han experimentado numerosas captaciones de estos acuíferos