TY - JOUR A1 - Zehe, Erwin A1 - Stehlik, Jiri A1 - Bárdossy, András T1 - Hydrologische Auswirkungen eines Klimaänderungsszenarios im Rheineinzugsgebiet Y1 - 2004 ER - TY - JOUR A1 - Zehe, Erwin A1 - Becker, Rolf A1 - Bardossy, Andras A1 - Plate, Erich T1 - Uncertainty of simulated catchment runoff response in the presence of threshold processes : role of initial soil moisture and precipitation N2 - This paper examines the effect of spatially variable initial soil moisture and spatially variable precipitation on predictive uncertainty of simulated catchment scale runoff response in the presence of threshold processes. The underlying philosophy is to use a physically based hydrological model named CATFLOW as a virtual landscape, assuming perfect knowledge of the processes. The model, which in particular conceptualizes preferential flow as threshold process, was developed based on intensive process and parameter studies and has already been successfully applied to simulate flow and transport at different scales and catchments. Study area is the intensively investigated Weiherbach catchment. Numerous replicas of spatially variable initial soil moisture or spatially variable precipitation with the same geostatistical properties are conditioned to observed soil moisture and precipitation data and serve as initial and boundary conditions for the model during repeated simulations. The effect of spatially soil moisture on modeling catchment runoff response was found to depend strongly on average saturation of the catchment. Different realizations of initial soil moisture yielded strongly different hydrographs for intermediate initial soil moisture as well as in dry catchment conditions; in other states the effect was found to be much lower. This is clearly because of the threshold nature of preferential flow as well as the threshold nature of Hortonian production of overland flow. It was shown furthermore that the spatial pattern of a key parameter (macroporosity) that determined threshold behavior is of vast importance for the model response. The estimation of these patterns, which is mostly done based on sparse observations and expert knowledge, is a major source for predictive model uncertainty. Finally, it was shown that the usage of biased, i.e. spatially homogenized precipitation, input during parameter estimation yields a biased model structure, which gives poor results when used with highly distributed input. If spatially highly resolved precipitation was used during model parameter estimation. the predictive uncertainty of the model was clearly reduced. (c) 2005 Elsevier B.V. All rights reserved Y1 - 2005 SN - 0022-1694 ER - TY - BOOK A1 - Zehe, Erwin A1 - Bolduan, Rainer A1 - Bärdossy, Andräs A1 - Bronstert, Axel A1 - Plate, Erich T1 - Stofftransport in einem Lösseinzugsgebiet: Experimentelle Evidenz und numerische Modellierung. Y1 - 2004 SN - 3-937758-18-6 ER - TY - JOUR A1 - Bronstert, Axel A1 - Bardossy, Andras T1 - Uncertainty of runoff modelling at the hillslope scale due to temporal variations of rainfall intensity Y1 - 2003 ER - TY - CHAP A1 - Zehe, Erwin A1 - Bronstert, Axel A1 - Itzerott, Sibylle A1 - Bárdossy, András A1 - Ihringer, Jürgen T1 - Hochwasservorhersage, Großhangbewegungen, Schadstofftransport BT - IMAF-relevante Projektbeispiele und Vorhaben am Institut für Geoökologie N2 - Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7128 ER - TY - JOUR A1 - Bárdossy, Andras A1 - Bronstert, Axel A1 - Buiteveld, Hendrik A1 - Disse, Markus A1 - Fritsch, Uta A1 - Katzenmaier, Daniel A1 - Lammersen, Rita T1 - Influence of the land surface and river training on flood conditions in the Rhine basin Y1 - 2000 ER - TY - JOUR A1 - Tarasova, Larisa A1 - Merz, Ralf A1 - Kiss, Andrea A1 - Basso, Stefano A1 - Blöchl, Günter A1 - Merz, Bruno A1 - Viglione, Alberto A1 - Plötner, Stefan A1 - Guse, Björn A1 - Schumann, Andreas A1 - Fischer, Svenja A1 - Ahrens, Bodo A1 - Anwar, Faizan A1 - Bárdossy, András A1 - Bühler, Philipp A1 - Haberlandt, Uwe A1 - Kreibich, Heidi A1 - Krug, Amelie A1 - Lun, David A1 - Müller-Thomy, Hannes A1 - Pidoto, Ross A1 - Primo, Cristina A1 - Seidel, Jochen A1 - Vorogushyn, Sergiy A1 - Wietzke, Luzie T1 - Causative classification of river flood events JF - Wiley Interdisciplinary Reviews : Water N2 - A wide variety of processes controls the time of occurrence, duration, extent, and severity of river floods. Classifying flood events by their causative processes may assist in enhancing the accuracy of local and regional flood frequency estimates and support the detection and interpretation of any changes in flood occurrence and magnitudes. This paper provides a critical review of existing causative classifications of instrumental and preinstrumental series of flood events, discusses their validity and applications, and identifies opportunities for moving toward more comprehensive approaches. So far no unified definition of causative mechanisms of flood events exists. Existing frameworks for classification of instrumental and preinstrumental series of flood events adopt different perspectives: hydroclimatic (large-scale circulation patterns and atmospheric state at the time of the event), hydrological (catchment scale precipitation patterns and antecedent catchment state), and hydrograph-based (indirectly considering generating mechanisms through their effects on hydrograph characteristics). All of these approaches intend to capture the flood generating mechanisms and are useful for characterizing the flood processes at various spatial and temporal scales. However, uncertainty analyses with respect to indicators, classification methods, and data to assess the robustness of the classification are rarely performed which limits the transferability across different geographic regions. It is argued that more rigorous testing is needed. There are opportunities for extending classification methods to include indicators of space-time dynamics of rainfall, antecedent wetness, and routing effects, which will make the classification schemes even more useful for understanding and estimating floods. This article is categorized under: Science of Water > Water Extremes Science of Water > Hydrological Processes Science of Water > Methods KW - flood genesis KW - flood mechanisms KW - flood typology KW - historical floods KW - hydroclimatology of floods Y1 - 2019 U6 - https://doi.org/10.1002/wat2.1353 SN - 2049-1948 VL - 6 IS - 4 PB - Wiley CY - Hoboken ER - TY - CHAP A1 - Eisele, Micha A1 - Bárdossy, András A1 - El Hachem, Abbas A1 - Seidel, Jochen A1 - Kröcher, Jenny A1 - Lischeid, Gunnar A1 - Pätzig, Marlene A1 - Shrestha, Rupesh A1 - Frankenberg, Philip A1 - Jüpner, Robert T1 - Nachlese vom Hydrologie Tag 2021 T2 - Hydrologie und Wasserbewirtschaftung : HyWa = Hydrology and water resources management, Germany / Hrsg.: Fachverwaltungen des Bundes und der Länder T2 - Gleanings from Hydrology Day 2021 Y1 - 2021 SN - 1439-1783 SN - 2749-859X VL - 65 IS - 6 SP - 298 EP - 298 PB - Bundesanstalt für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - Nguyen Nghia Hung, A1 - Delgado, José Miguel Martins A1 - Guentner, Andreas A1 - Merz, Bruno A1 - Bardossy, Andras A1 - Apel, Heiko T1 - Sedimentation in the floodplains of the Mekong Delta, Vietnam Part II: deposition and erosion JF - Hydrological processes N2 - Deposition and erosion play a key role in the determination of the sediment budget of a river basin, as well as for floodplain sedimentation. Floodplain sedimentation, in turn, is a relevant factor for the design of flood protection measures, productivity of agro-ecosystems, and for ecological rehabilitation plans. In the Mekong Delta, erosion and deposition are important factors for geomorphological processes like the compensation of deltaic subsidence as well as for agricultural productivity. Floodplain deposition is also counteracting the increasing climate change induced hazard by sea level rise in the delta. Despite this importance, a sediment database of the Mekong Delta is lacking, and the knowledge about erosion and deposition processes is limited. In the Vietnamese part of the Delta, the annually flooded natural floodplains have been replaced by a dense system of channels, dikes, paddy fields, and aquaculture ponds, resulting in floodplain compartments protected by ring dikes. The agricultural productivity depends on the sediment and associated nutrient input to the floodplains by the annual floods. However, no quantitative information regarding their sediment trapping efficiency has been reported yet. The present study investigates deposition and erosion based on intensive field measurements in three consecutive years (2008, 2009, and 2010). Optical backscatter sensors are used in combination with sediment traps for interpreting deposition and erosion processes in different locations. In our study area, the mean calculated deposition rate is 6.86kg/m(2) (approximate to 6mm/year). The key parameters for calculating erosion and deposition are estimated, i.e. the critical bed shear stress for deposition and erosion and the surface constant erosion rate. The bulk of the floodplain sediment deposition is found to occur during the initial stage of floodplain inundation. This finding has direct implications on the operation of sluice gates in order to optimize sediment input and distribution in the floodplains. KW - Mekong delta KW - sediment dynamics KW - deposition KW - erosion KW - floodplain sedimentation Y1 - 2014 U6 - https://doi.org/10.1002/hyp.9855 SN - 0885-6087 SN - 1099-1085 VL - 28 IS - 7 SP - 3145 EP - 3160 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Nguyen Nghia Hung, A1 - Delgado, José Miguel Martins A1 - Güntner, Andreas A1 - Merz, Bruno A1 - Bardossy, Andras A1 - Apel, Heiko T1 - Sedimentation in the floodplains of the Mekong Delta, Vietnam. Part I: suspended sediment dynamics JF - Hydrological processes N2 - Suspended sediment is the primary source for a sustainable agro-ecosystem in the Mekong Delta by providing nutrient input for the subsequent cropping season. In addition, the suspended sediment concentration (SSC) plays an important role in the erosion and deposition processes in the Delta; that is, it influences the morphologic development and may counteract the deltaic subsidence and sea level rise. Despite this importance, little is known about the dynamics of suspended sediment in the floodplains of the Mekong Delta. In particular, quantitative analyses are lacking mainly because of data scarcity with respect to the inundation processes in the floodplains. In 2008, therefore, a comprehensive in situ system to monitor the dynamics of suspended sediment in a study area located in the Plain of Reeds was established, aiming at the characterization and quantification of suspended sediment dynamics in the deeply inundated parts of the Vietnamese part of the Mekong Delta. The monitoring system was equipped with seven water quality-monitoring stations. They have a robust design and autonomous power supply suitable for operation on inundated floodplains, enabling the collection of reliable data over a long period of time with a high temporal resolution. The data analysis shows that the general seasonal dynamics of suspended sediment transport in the Delta is controlled by two main mechanisms: the flood wave of the Mekong River and the tidal backwater influences from the coast. In the channel network, SSC decreases exponentially with distance from the Mekong River. The anthropogenic influence on SSC could also be identified for two periods: at the start of the floodplain inundation and at the end of the flood period, when subsequent paddy rice crops are prepared. Based on the results, we recommend an operation scheme for the sluice gates, which intends to distribute the sediment and thus the nutrients equally over the floodplain. KW - Mekong Delta KW - floodplain KW - suspended sediment KW - sediment dynamics KW - floodplain sedimentation Y1 - 2014 U6 - https://doi.org/10.1002/hyp.9856 SN - 0885-6087 SN - 1099-1085 VL - 28 IS - 7 SP - 3132 EP - 3144 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Nguyen Viet Dung, A1 - Merz, Bruno A1 - Bardossy, Andras A1 - Apel, Heiko T1 - Handling uncertainty in bivariate quantile estimation - An application to flood hazard analysis in the Mekong Delta JF - Journal of hydrology N2 - The hydrological load causing flood hazard is in many instances not only determined by peak discharge, but is a multidimensional problem. While the methodology for multivariate frequency analysis is well established, the estimation of the associated uncertainty is rarely studied. In this paper, a method is developed to quantify the different sources of uncertainty for a bivariate flood frequency analysis. The method is exemplarily developed for the Mekong Delta (MD), one of the largest and most densely populated river deltas worldwide. Floods in the MD are the basis for the livelihoods of the local population, but they are also the major hazard. This hazard has, however, not been studied within the frame of a probabilistic flood hazard analysis. The nature of the floods in the MD suggests a bivariate approach, because the societal flood severity is determined by both peak discharge and flood volume. The uncertainty caused by selection of statistical models and parameter estimation procedures are analyzed by applying different models and methods. For the quantification of the sampling uncertainty two bootstrapping methods were applied. The developed bootstrapping-based uncertainty estimation method shows that large uncertainties are associated with the estimation of bivariate flood quantiles. This uncertainty is much larger than the model selection and fitting uncertainty. Given the rather long data series of 88 years, it is concluded that bivariate flood frequency analysis is expected to carry significant uncertainty and that the quantification and reduction of uncertainty merit greater attention. But despite this uncertainty the proposed approach has certainly major advantages compared to a univariate approach, because (a) it reflects the two essential aspects of floods in this region, (b) the uncertainties are inherent for every bivariate frequency analysis in hydrology due to the general limited length of observations and can hardly be avoided, and (c) a framework for the quantification of the uncertainties is given, which can be used and interpreted in the hazard assessment. In addition it is shown by a parametric bootstrapping experiment how longer observation time series can reduce the sampling uncertainty. Based on this finding it is concluded that bivariate frequency analyses in hydrology would greatly benefit from discharge time series augmented by proxy or historical data, or by causal hydrologic expansion of time series. (C) 2015 Elsevier B.V. All rights reserved. KW - Bivariate flood quantile KW - Copulas KW - Uncertainty estimation KW - Bootstrapping KW - Mekong Delta Y1 - 2015 U6 - https://doi.org/10.1016/j.jhydrol.2015.05.033 SN - 0022-1694 SN - 1879-2707 VL - 527 SP - 704 EP - 717 PB - Elsevier CY - Amsterdam ER -