TY - BOOK A1 - Bronstert, Axel A1 - Seiert, S. A1 - Oberholzer, Gustav T1 - Maßnahmen der Flurbereinigung und ihre Wirkung auf das Abflußverhalten ländlicher Gebiete : gemeinsamer Bericht des Instituts für Hydrologie und Wasserwirtschaft, Universität Karlsruhe, und des Instituts für Liegenschaftswesen, Planung und Bodenordnung, Universität der Bundeswehr, Neubiberg bei München T3 - Flurneuordnung und Landentwicklung Baden Württemberg Y1 - 1993 VL - 3 PB - LfU CY - Karlsruhe ER - TY - BOOK A1 - Bronstert, Axel A1 - Jürgens, M. T1 - Modellsystem Hillflow : physikalisch begründete und flächendetalierte Modellierung der Abflußbildung und der Bodenwasserdynamik von ebenen Standorten, Hängen und Kleineinzugsgebieten ; Modelldokumentation und Benutzerhandbuch, Version 1.0 Y1 - 1994 PB - Inst. für Hydrologie und Wasserwirtschaft, Universität Karlsruhe CY - Karlsruhe ER - TY - JOUR A1 - Tittel, Jörg A1 - Bork, Rudolf A1 - Röpke, Björn A1 - Geldmacher, Karl A1 - Schnur, Tilo A1 - Faust, Berno A1 - Schaphoff, Sibyll A1 - Dalchow, Claus A1 - Woithe, Franka A1 - Bronstert, Axel A1 - Jeltsch, Florian A1 - Jessel, Beate A1 - Zschalich, Andrea A1 - Rößling, Holger A1 - Spindler, Joris A1 - Gaedke, Ursula A1 - Tielbörger, Katja A1 - Kadmon, R. A1 - Müller, J. A1 - Bissinger, Vera A1 - Weithoff, Guntram A1 - Wallschläger, Hans-Dieter A1 - Wiegleb, Gerhard T1 - Umweltforschung für das Land Brandenburg BT - Projekt Ökologie und Naturschutz / Landschaftsplanung / Landschaftsentwicklung JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam N2 - BISSINGER, V.; TITTEL, J.: Process rates and growth limiting factors of planktonic algae (Chlamydomonas sp.) from extremely acidic (pH 2,5 - 3) mining lakes in Germany ; BORK, H.-R. et al.: Erodierte Autos und Brunnen in Oregon, USA ; BRONSTERT, A. et al.: Bewirtschaftunsmöglichkeiten im Einzugsgebiet der Havel ; JELTSCH, F. et al.: Beweidung als Degradationsfaktor in ariden und semiariden Weidesystemen ; JELTSCH, F. et al.: Entstehung und Bedeutung räumlicher Vegetationsstrukturen in Trockensavannen: Baum-Graskoexistenz und Artenvielfalt ; JESSEL, B. et al.: Bodenbewertung für Planungs- und Zulassungsverfahren in Brandenburg ; JESSEL, B.; ZSCHALICH, A.: Erarbeitung von Ausgleichs- und Ersatzmaßnahmen für die Wert- und Funktionselemente des Landschaftsbildes ; RÖßLING, H. et al.: Umsetzung von Ausgleichs- und Ersatzmaßnahmen beim Ausbau der Bundesautobahn A 9 ; SPINDLER, J.; GAEDKE, U.: Estimating production in plankton food webs from biomass size spectra and allometric relationships ; TIELBÖRGER, K. et al.: Sukzessionsprozesse in einem Sanddünengebiet nach Ausschluß von Beweidung ; TIELBÖRGER, K. et al.: Populationsdynamische Funktionen von Ausbreitung und Dormanz ; TIELBÖRGER, K. et al.: Raum-zeitliche Populationsdynamik von einjährigen Wüstenpflanzen ; TITTEL, J. et al.: Ressourcennutzung und -weitergabe im planktischen Nahrungsnetz eines extrem sauren (pH 2,7) Tagebausees ; WALLSCHLÄGER, D.; WIEGLEB, G.: Offenland-Management auf ehemaligen und in Nutzung befindlichen Truppenübungsplätzen im pleistozänen Flachland Nordostdeutschlands: Naturschutzfachliche Grundlagen und praktische Anwendungen ; WEITHOFF, G.; GAEDKE, U.: Planktische Räuber-Beute-Systeme: Experimentelle Untersuchung von ökologischen Synchronisationen Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3828 SN - 1434-2375 SN - 1611-9339 VL - 8 SP - 80 EP - 134 ER - TY - JOUR A1 - Blumenstein, Oswald A1 - Bronstert, Axel A1 - Günter, A. A1 - Katzenmeier, D. A1 - Friedrich, Sabine A1 - Geldmacher, Karl A1 - Bork, Rudolf A1 - Röpke, Björn A1 - Schaphoff, Sibyll A1 - Schnur, Tilo A1 - Woithe, Franka A1 - Dalchow, Claus A1 - Faust, Berno A1 - Itzerott, Sibylle A1 - Kaden, Klaus A1 - Knösche, Rüdiger T1 - Umweltforschung für das Land Brandenburg BT - Projekt Schutzgüter Wasser, Boden, Luft JF - Brandenburgische Umwelt-Berichte : BUB ; Schriftenreihe der Mathematisch-Naturwissenschaftlichen Fakultät der Universität Potsdam N2 - BLUMENSTEIN, O.: Investigation of Environmental Quality and Social Structures in a Mining Area in the North West Province of South Africa ; BRONSTERT, A.; GÜNTNER, A.: A large-scale hydrological model for the semi-arid environment of north-eastern Brazil ; BRONSTERT, A. et al.: Hochwasserproblematik und der Zusammenhang mit Landnutzungs- und Klimaänderungen ; FRIEDRICH, S.: Vergleichende Untersuchungen zur Wasserqualität des anfallenden Regenwassers an den 14 Regenwassereinläufen der Stadt Potsdam ; GELDMACHER, K. et al.: Bodenzerstörung im Palouse, Washington, USA ; ITZEROTT, S.; KADEN, K.: Modellierung der flächenhaften Verdunstung im Gebiet der Unteren Havel ; KNÖSCHE, R.: Das remobilisierbare Nährstoffpotential in Augewässersedimenten einer Tieflandflußaue Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3845 SN - 1434-2375 SN - 1611-9339 VL - 8 SP - 136 EP - 173 ER - TY - JOUR A1 - Bronstert, Axel A1 - Fritsch, Uta A1 - Katzenmaier, Daniel A1 - Bismuth, Christine T1 - Quantification of the influence of the land-surface and river training on flood discharge of the Rhine Basin Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Krol, Marten S. A1 - Jaeger, Annekathrin T1 - WAVES : water availability, vulnerability of ecosystems and society in northeast brazil ; an overview of the interdisciplinary project and integrated modelling Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Katzenmaier, Daniel A1 - Fritsch, Uta T1 - Hochwasserproblematik und der Zusammenhang mit Landnutzungs- und Klimaänderungen Y1 - 2000 ER - TY - JOUR A1 - Fritsch, Uta A1 - Katzenmaier, Daniel A1 - Bronstert, Axel T1 - Land-use and land-cover scenarios for flood risk analysis and river basin management Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Köhler, Birgit T1 - Simulation der Einflüsse anthropogener Klimaänderungen auf die Hochwasserentstehung : eine Fallstudie in einem kleinen ländlichen Einzugsgebiet im Ostharz Y1 - 2000 ER - TY - JOUR A1 - Katzenmaier, Daniel A1 - Fritsch, Uta A1 - Bronstert, Axel T1 - Influences of land-use and land-cover changes on storm-runoff generation Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel T1 - The possible impacts of environmental changes on flood formation : relevant processes and model requirements Y1 - 2000 ER - TY - JOUR A1 - Menzel, Lucas A1 - Bronstert, Axel A1 - Bürger, Gerd A1 - Krysanova, Valentina T1 - Environmental change scenarios and flood responses in the Elbe catchment (Germany) Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Kundzewicz, Zbigniew W. A1 - Menzel, Lucas T1 - Achievements and future needs towards improved flood protection in the Oder river basin : results of the EU- expert meeting on the Oder flood in Summer '97 Y1 - 2000 SN - 0-7923-6451-1, 0-7923-6452-X ER - TY - JOUR A1 - Bronstert, Axel A1 - Lahmer, Werner T1 - Bewirtschaftungsmöglichkeiten im Einzugsgebiet der Havel Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Güntner, Andreas T1 - A large-scale hydrological model for the semi-arid environment of north-eastern Brazil Y1 - 2000 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 - Niehoff, Daniel A1 - Bronstert, Axel T1 - Influences of land-use and land-surface conditions on flood generation : a simulation study Y1 - 2000 ER - TY - JOUR A1 - Bronstert, Axel A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Güntner, Andreas A1 - Hauschild, M. A1 - Döll, P. T1 - Integrated modelling of water availability an management in the semi-arid Notheast of Brazil Y1 - 2000 ER - TY - CHAP A1 - Lück, Erika A1 - Balderjahn, Ingo A1 - Kamm, Birgit A1 - Greil, Holle A1 - Wallschläger, Hans-Dieter A1 - Jessel, Beate A1 - Böckmann, Christine A1 - Oberhänsli, Roland A1 - Soyez, Konrad A1 - Schmeer, Ernst A1 - Blumenstein, Oswald A1 - Berndt, Klaus-Peter A1 - Edeling, Thomas A1 - Friedrich, Sabine A1 - Kaden, Klaus A1 - Scheller, Frieder W. A1 - Petersen, Hans-Georg A1 - Asche, Hartmut A1 - Bronstert, Axel A1 - Giest, Hartmut A1 - Gaedke, Ursula A1 - Löhmannsröben, Hans-Gerd A1 - Jeltsch, Florian A1 - Jänkel, Ralph A1 - Gzik, Axel A1 - Bork, Hans-Rudolf A1 - Bork, Hans-Rudolf T1 - Umweltforschung für das Land Brandenburg : Arbeitsgruppen und Professuren Y1 - 2000 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-3797 ER - TY - JOUR A1 - Bronstert, Axel T1 - The role of infiltration conditions for storm runoff generation at the hillslope and small catchment scale Y1 - 2001 ER - TY - JOUR A1 - Katzenmaier, Daniel A1 - Fritsch, Uta A1 - Bronstert, Axel T1 - Quantifizierung des Einflusses von Landnutzung und dezentraler Versickerung auf die Hochwasserentstehung Y1 - 2001 SN - 3-503-06021-9 ER - TY - JOUR A1 - Bronstert, Axel A1 - Menzel, Lucas A1 - Middelkoop, H. A1 - de Roo, A. P. A1 - Van Beek, E. T1 - River basin research and management : integrated modelling and investigation of land-use impacts on the hydrological cycle Y1 - 2001 ER - TY - JOUR A1 - Bronstert, Axel A1 - Fritsch, Uta A1 - Leonhardt, H. A1 - Niehoff, Daniel T1 - Quantifizierung des Einflusses von Landnutzungs- und Klimaänderungen auf die Hochwasserentstehung am Beispiel ausgewählter Flussgebiete Y1 - 2001 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Modelling the effects of climate change on water availability in the semi-arid of North-East Brazil Y1 - 2001 ER - TY - JOUR A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Bronstert, Axel A1 - Krywkow, J. T1 - The Semi-arid Integrated Model (SIM), a regional integrated model assessing water availability, vulnerability of ecosystems and society in NE-Brazil Y1 - 2001 ER - TY - JOUR A1 - Niehoff, Daniel A1 - Bronstert, Axel T1 - Influences of land-use and land-surface conditions on flood generation : a simulation study Y1 - 2001 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - WAVES - Water availability, vulnerability of ecosystems and society in the northeast of Brazil : sub-project large-scale hydrological modelling Y1 - 2001 ER - TY - BOOK A1 - Kundzewicz, Zbigniew W. A1 - Budhakooncharoen, Saisunee A1 - Bronstert, Axel A1 - Hoff, Holger A1 - Lettenmaier, Dennis P. A1 - Menzel, Lucas A1 - Schulze, Roland T1 - Floods and droughts : coping with variability and climate change ; thematic backround paper [for the International Conference on Freshwater 2001, Bonn, 3-7 December 2001] Y1 - 2001 UR - http://www.water-2001.de/co_doc/Floods.pdf PB - Secretariat of the International Conference on Freshwater CY - Bonn ER - TY - JOUR A1 - Kundzewicz, Zbigniew W. A1 - Budhakooncharoen, Saisunee A1 - Bronstert, Axel A1 - Hoff, Holger A1 - Lettenmaier, Dennis P. A1 - Menzel, Lucas A1 - Schulze, Roland T1 - Coping with variability and climate change : floods and droughts Y1 - 2001 ER - TY - JOUR A1 - Bronstert, Axel A1 - Niehoff, Daniel A1 - Bürger, Gerd T1 - Effects of climate and land-use change on storm runoff generation : present knowledge and modelling capabilities Y1 - 2002 ER - TY - JOUR A1 - Menzel, Lucas A1 - Niehoff, Daniel A1 - Bürger, Gerd A1 - Bronstert, Axel T1 - Climate change impacts on river flooding : a modelling study of three meso-scale catchments Y1 - 2002 ER - TY - JOUR A1 - Niehoff, Daniel A1 - Fritsch, Uta A1 - Bronstert, Axel T1 - Land-use impacts on storm-runoff generation : scenarios of land-use change and simulation of hydrological response in a meso-scale catchment in SW-Germany Y1 - 2002 ER - TY - JOUR A1 - Bronstert, Axel A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Güntner, Andreas T1 - Integrated modelling of climate, water, soil, agricultural and socio-economic processes : a general introduction to the methodology and some exemplary results from the semi-arid Northeast of Brazil Y1 - 2002 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Process-based modelling of large-scale water availability in a semi-arid environment : process representation and scaling issues Y1 - 2002 ER - TY - JOUR A1 - Niehoff, Daniel A1 - Bronstert, Axel T1 - Landnutzung und Hochwasserentstehung : Modellierung anhand dreier mesoskaliger Einzugsgebiete Y1 - 2002 ER - TY - JOUR A1 - Bronstert, Axel A1 - Menzel, Lucas T1 - Advances in Flood Research Y1 - 2002 ER - TY - JOUR A1 - Bronstert, Axel T1 - Floods and climate change : interactions and impacts Y1 - 2003 SN - 0272-4332 ER - TY - JOUR A1 - Günter, A. A1 - Bronstert, Axel T1 - Large-scale hydrological modelling of a semi-arid environment : model development, validation and application Y1 - 2003 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 - JOUR A1 - Krol, Marten S. A1 - Jaeger, Annekathrin A1 - Bronstert, Axel T1 - Integrated modelling of climate change impacts in northeastern brazil Y1 - 2003 ER - TY - JOUR A1 - Pfister, L. A1 - Kwadijk, J. A1 - Musy, A. A1 - Bronstert, Axel A1 - Hoffmann, L. T1 - Climate change, land use change and run-off prediction in the Rhine-Meuse basins N2 - As a consequence of increasing winter rainfall totals and intensities over the second half of the 20th century, signs of increased flooding probability in many areas of the Rhine and Meuse basins have been documented. These changes affecting rainfall characteristics are most evidently due to an increase in westerly atmospheric circulation types. Land use changes, particularly urbanization, can have significant local effects in small basins (headwaters) with respect to flooding, especially during heavy local rainstorms, but no evidence exists that land use change has had significant effects on peak flows in the rivers Rhine and Meuse. For the 21st century, most global circulation models suggest higher winter rainfall totals. Most hydrological simulations of the Rhine-Meuse river basins suggest an increased flooding probability, with a progressive shift of the Rhine from a 'rain-fed/meltwater' river into a mainly 'rain-fed' river. A very limited effect of changes in land use on the discharge regime seems to exist for the main branches of the Meuse and Rhine rivers. For mesoscale basins, future changes in peak flows depend on the changes in the variability of extreme precipitations in combination with land use changes. Copyright (C) 2004 John Wiley Sons, Ltd Y1 - 2003 SN - 1535-1459 ER - TY - JOUR A1 - Bronstert, Axel T1 - Rainfall-runoff modelling for assessing impacts of climate and land-use change Y1 - 2004 ER - TY - JOUR A1 - Bronstert, Axel T1 - Probleme, Grenzen und Herausforderungen der hydrologischen Modellierung: Wasserhaushalt und Abfluss Y1 - 2004 ER - TY - JOUR A1 - Krause, Stefan A1 - Bauer, Andreas A1 - Morgner, Markus A1 - Bronstert, Axel T1 - Wasserhaushaltsmodellierung als Beitrag zur Erstellung eines nachhaltigen Flusseinzugsgebietsmanagements an der Unteren Havel Y1 - 2004 SN - 3-937758-18-6 ER - TY - JOUR A1 - Krause, Stefan A1 - Bronstert, Axel T1 - Approximation of Groundwater - Surface Water - Interactions in a Mesoscale Lowland River Catchment Y1 - 2004 ER - TY - JOUR A1 - Kneis, David A1 - Knösche, Rüdiger A1 - Bronstert, Axel T1 - Ist eine Auswaschung von Nährstoffen aus Flussgewässersedimenten eine realistische Option zur Trophiesenkung? Y1 - 2004 SN - 3-937758-18-6 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 - Blume, Theresa A1 - Bauer, Andreas A1 - Bronstert, Axel T1 - Experimental techniques for the Investigation of Runoff Processes in a Small Catchment in the Chilean Andes Y1 - 2004 SN - 3-937758-18-6 ER - TY - JOUR A1 - Krause, Stefan A1 - Bronstert, Axel T1 - Wasserhaushaltssimulationen unter Einbeziehung von Grundwasser - Oberflächenwasser - Kopplung zur Optimierung szenarienbasierter Handlungsoptionen für ein nachhaltiges Flussgebietsmanagement an der Unteren Havel Y1 - 2004 SN - 3-89958-072-9 ER - TY - JOUR A1 - Kneis, David A1 - Knösche, Rüdiger A1 - Bronstert, Axel T1 - Ist ein Netto-Nährstoffexport aus Flussgewässersedimenten eine realistische Option zur Trophiesenkung? Y1 - 2004 SN - 3-937758-18-6 ER - TY - JOUR A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Representation of landscape variability and lateral redistribution processes for large-scale hydrological modelling in semi-arid areas N2 - The spatial variability of landscape features such as topography, soils and vegetation defines the spatial pattern of hydrological state variables like soil moisture. Spatial variability thereby controls the functional behaviour of the landscape in terms of its runoff response. A consequence of spatial variability is that exchange processes between landscape patches can occur at various spatial scales ranging from the plot to the basin scale. In semi-arid areas, the lateral redistribution of surface runoff between adjacent landscape patches is an important process. For applications to large river basins of 10(4)-10(5) km(2) in size, a multi-scale landscape discretization scheme is presented in this paper. The landscape is sub-divided into modelling units within a hierarchy of spatial scale levels. By delineating areas characterized by a typical toposequence, organised and random variability of landscape characteristics is captured in the model. Using runoff-runon relationships with transition frequencies based on areal fractions of modelling units, lateral surface and subsurface water fluxes between modelling units at the hillslope scale are represented. Thus, the new approach allows for a manageable description of interactions between fine-scale landscape features for inclusion in coarse-scale models. Model applications for the State of Ceara (148,000 km(2)) in the north- east of Brazil demonstrate the importance of taking into account landscape variability and interactions between landscape patches in a semi-arid environment. Using mean landscape characteristics leads to a considerable underestimation of infiltration-excess surface runoff and total simulated runoff. Re-infiltration of surface runoff and lateral redistribution processes between landscape patches cause a reduction of runoff volumes at the basin scale and contribute to the amplification of variations in runoff volumes relative to variations in rainfall volumes for semi-arid areas. (C) 2004 Elsevier B.V. All rights reserved Y1 - 2004 SN - 0022-1694 ER - TY - JOUR A1 - Güntner, Andreas A1 - Krol, Marten S. A1 - de Arajo, José Carlos A1 - Bronstert, Axel T1 - Simple water balance modelling of surface reservoir systems in a large data-scarce semiarid region N2 - Water resources in dryland areas are often provided by numerous surface reservoirs. As a basis for securing future water supply, the dynamics of reservoir systems need to be simulated for large river basins, accounting for environmental change and an increasing water demand. For the State of Ceara in semiarid Northeast Brazil, with several thousands of reservoirs, a simple deterministic water balance model is presented. Within a cascade-type approach, the reservoirs are grouped into six classes according to storage capacity, rules for flow routing between reservoirs of different size are defined, and water withdrawal and return flow due to human water use is accounted for. While large uncertainties in model applications exist, particularly in terms of reservoir operation rules, model validation against observed reservoir storage volumes shows that the approach is a reasonable simplification to assess surface water availability in large river basins. The results demonstrate the large impact of reservoir storage on downstream flow and stress the need for a coupled simulation of runoff generation, network redistribution and water use Y1 - 2004 SN - 0262-6667 ER - TY - BOOK A1 - Bronstert, Axel A1 - Thieken, Annegret A1 - Merz, Bruno A1 - Rode, Michael A1 - Menzel, Lucas T1 - Wasser- und Stofftransport in heterogenen Einzugsgebieten : Beiträge zum Tag der Hydrologie 2004, 22./ 23. März 2004 in Potsdam ; Bd. 2 Poster Y1 - 2004 SN - 3-937758-18-6 PB - ATV-DVWK CY - Hennef ER - TY - BOOK A1 - Bronstert, Axel A1 - Thieken, Annegret A1 - Merz, Bruno A1 - Rode, Michael A1 - Menzel, Lucas T1 - Wasser- und Stofftransport in heterogenen Einzugsgebieten : Beiträge zum Tag der Hydrologie 2004, 22./ 23. März 2004 in Potsdam ; Bd. 1 Vorträge Y1 - 2004 SN - 3-937758-18-6 VL - 5 PB - ATV-DVWK CY - Hennef (Sieg) ER - TY - BOOK A1 - Bronstert, Axel A1 - Carrera, Jesus A1 - Kabat, Pavel A1 - Lütkemeier, Sabine T1 - Coupled models for the hydrological cycle : integrating atmosphere, biosphere and pedosphere Y1 - 2005 SN - 3-540-22371-1 U6 - https://doi.org/10.1007/b138919 PB - Springer-Verlag Berlin Heidelberg CY - Berlin, Heidelberg ER - TY - JOUR A1 - Bronstert, Axel A1 - Engel, H. T1 - Veränderung der Abflüsse JF - Warnsignal Klima - genug Wasser für alle? : wissenschaftliche Fakten Y1 - 2005 SN - 978-3-9809668-0-1 SP - 175 EP - 181 PB - Wissenschaftliche Auswertungen CY - Hamburg ER - TY - JOUR A1 - Krol, Maarten A1 - Jaeger, Annekathrin A1 - Bronstert, Axel A1 - Güntner, Andreas T1 - Integrated modelling of climate, water, soil, agricultural and socio-economic processes: A general introduction of the methodology and some exemplary results from the semi-arid north-east of Brazil JF - Journal of hydrology N2 - Many semi-arid regions are characterised by water scarcity and vulnerability of natural resources, pronounced climatic variability and social stress. Integrated studies including climatotogy, hydrology, and socio-econornic studies are required both for analysing the dynamic natural conditions and to assess possible strategies to make semi-arid regions Less vulnerable to the present and changing climate. The model introduced here dynamically describes the retationships between climate forcing, water availability, agriculture and selected societal processes. The model has been tailored to simulate the rather complex situation in the semi-and north-eastern Brazil in a quantitative manner including the sensitivity to external forcing, such as climate change. The selected results presented show the general functioning of the integrated model, with a primary focus on climate change impacts. It becomes evident that due to Large differences in regional climate scenarios, it is still impossible to give quantitative values for the most probable development, e.g., to assign probabilities to the simulated results. However, it becomes clear that water is a very crucial factor, and that an efficient and ecologically sound water management is a key question for the further development of that semi-arid region. The simulation results show that, independent of the differences in climate change scenarios, rain-fed farming is more vulnerable to drought impacts compared to irrigated farming. However, the capacity of irrigation and other water infrastructure systems to enhance resilience in respect to climatic fluctuations is significantly constrained given a significant negative precipitation trend. (c) 2005 Elsevier B.V. All rights reserved. KW - integrated modelling KW - integrated river basin management KW - water resources management KW - semi-arid hydrology KW - climate change Y1 - 2006 U6 - https://doi.org/10.1016/j.jhydrol.2005.12.021 SN - 0022-1694 VL - 328 IS - 3-4 SP - 417 EP - 431 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - De Araujo, Josè Carlos A1 - Güntner, Andreas A1 - Bronstert, Axel T1 - Loss of reservoir volume by sediment deposition and its impact on water availability in semiarid Brazil N2 - A methodology is presented to assess the impact of reservoir silting oil water availability for semiarid environments, applied to seven representative watersheds in the state of Ceara, Brazil. Water yield is computed using stochastic modelling for several reliability levels and water yield reduction is quantified for the focus areas. The yield-volume elasticity concept, which indicates the relative yield reduction in terms of relative storage capacity of the reservoirs, is presented and applied. Results chow that storage capacity was reduced by 0.2% year(-1) due to silting, that the risk of water shortage almost doubled in less than 50 years for the most critical reservoir, and that reduction of storage capacity had three times more impact oil yield reduction than the increase in evaporation. Average 90% reliable yield-volume elasticity was 0.8, which means that the global water yield (Q(90)) in Ceara is expected to diminish yearly by 388 L s(-1) due to reservoir silting Y1 - 2006 UR - http://www.atypon-link.com/IAHS/loi/hysj U6 - https://doi.org/10.1623/hysj.51.1.157 SN - 0262-6667 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 - CHAP A1 - Bronstert, Axel T1 - Interdisziplinäres Zentrum für Musterdynamik und angewandte Fernerkundung (IMAF) an der Universität Potsdam : Gegenwart und Zukunft N2 - Stand des IMAF zu Beginn des Jahres 2006 Zum 1. April 2005 wurde per Beschluss des Rektorats der Universität Potsdam das Interdisziplinäre Zentrum für Musterdynamik und Angewandte Fernerkundung (IMAF) an der Universität Potsdam eingerichtet. Diesem Beschluss gingen knapp zwei Jahre konzeptionelle, organisatorische und administrative Vorarbeiten voraus. Inzwischen ist das IMAF also offiziell gegründet, der Vorstand wurde „bestellt“ (Prof. M. Mutti. Prof. E. Zehe, Prof. A. Bronstert), der Geschäftsführer bzw. wissenschaftliche Koordinator Dr. M. Kühling arbeitet in dieser Funktion seit Sommer 2005 und seit kurzem ist auch die 1. Version der Homepage des IMAF (http://www.uni-potsdam.de/imaf/) frei geschaltet. Auch die Infrastruktur des IMAF ist in der Entstehungsphase: Büroräume sind versprochen (wenn auch noch nicht bezugsfertig) im Haus 13 auf dem Campus Golm der Universität Potsdam und der 1. erfolgreiche Drittmittelantrag erbrachte 8 leistungsfähige Tischrechner und einen Server für das IMAF aus EU-Mitteln. Wichtiger als die administrativen und organisatorischen Arbeiten sind aber die inhaltlichen Forstschritte. Hier ist die große Resonanz, die die Gründung des IMAF sowohl innerhalb als auch außerhalb der Universität gefunden hat, besonders erfreulich. Über 30 Angehörige des Zentrums sind inzwischen zu verzeichnen und es gibt bereits eine Reihe von wissenschaftlichen Projektinitiativen und Ideen für dieses Zentrum. Neben den wissenschaftlichen Arbeiten am IMAF ist ein zweites Hauptziel für dieses Zentrum die Entwicklung und der Ausbau eines strukturierten Ausbildungsangebotes für Musterdynamik und angewandte Fernerkundung. Dies sollen gleichermaßen Masterstudenten als auch Doktoranden der Universität Potsdam und der mit ihr assoziierten außeruniversitären Institute nutzen. Zudem werden Kurse und Weiterbildungsveranstaltungen mit nationalen und internationalen Experten angestrebt. Neben diesen positiven Entwicklungen gibt es auch (noch ??) über einige Mängel zu berichten: Das Sekretariat ist nach wie vor unbesetzt, die Finanzausstattung des Zentrums ist völlig ungenügend und die im Konzept für das Zentrum beantragte Wissenschaftlerstelle für Softwareanwendung ist nicht in Sicht. Für einen Erfolg des Zentrums ist es unbedingt notwendig, dass sich diese Situation deutlich verbessert!! Forschungsschwerpunkte des IMAF Räumliche Muster und deren Struktur in der Umwelt Räumliche Muster sind in vielen naturwissenschaftlichen Disziplinen (Hydrologie, Ökologie, Geologie, Biologie, Chemie, Physik) von zentraler Bedeutung. Z.B. bestimmen die räumlichen (und zeitlichen) Muster von Bodeneigenschaften und Vegetation in ihrem Zusammenspiel mit den Mustern von Niederschlag und Strahlungsinput maßgeblich den Wasser- und Stoffhaushalt auf unterschiedlichsten Skalen und führen über Rückkopplung wiederum zu Veränderungen in Klima, Vegetation und Ökosystemen. Vom kleinräumigen Transport von Schadstoffen und von der Hochwasserentstehung bis zur Frage nach den regionalen und globalen Veränderungen von Klima, Vegetation und Landnutzung seien hier nur einige Problemkreise genannt, in denen Muster und Musterdynamik eine zentrale Stellung einnehmen. Darüber hinaus liefert die Betrachtung der zeitlichen Veränderung von räumlichen Mustern, in Ergänzung zur klassischen Erfassung dynamischer Prozesse in Form von Messungen lokaler zeitlicher Änderungen, eine völlig neue Perspektive auf Dynamik und eröffnet damit völlig neue wissenschaftliche Möglichkeiten. Aktuelle und sehr drängende Fragen innerhalb dieses Forschungsschwerpunktes sind unter anderem: • Analyse der generelle Raumstruktur von Geodaten (Variabilität, Struktur, Konnektivität); • Thematische Verbindungen verschiedener Datenebenen und Möglichkeiten für deren Assimilation; • Möglichkeiten und Grenzen des Skalenübergangs zwischen verschiedenen räumlichen Auflösungen und Informationsquellen; • Ableitung der zeitlichen Dynamik bzw. Entwicklung von großen flächenhaften Datenfeldern. Angewandte Fernerkundung Wie keine andere Technik bietet die Fernerkundung in jeglicher Form (unter anderem Satelliten, flugzeuggetragene Sensoren, Wetterradar und auch geophysikalische Methoden) umfangreiche Möglichkeiten, räumliche Muster und deren zeitliche Veränderungen zu erfassen. Allen Methoden der Fernerkundung gemein ist, dass sie nur indirekte Ergebnisse liefern. Das heißt, es besteht nur ein mittelbarer Zusammenhang zwischen dem beobachteten Signal, meist der Reflektivität oder Emissivität elektromagnetischer Strahlung in verschiedenen Spektralbereichen (optisch oder Radar), und der eigentlich interessierenden Größe, wie dem Feuchtezustand der Vegetation, der Bodenfeuchte oder Bodenrauhigkeit, der Niederschlagsintensität, dem Zustand der Schneedecke oder der Ausdehnung eines Oberflächenfilms auf Gewässern. Ein Satellitenbild enthält beispielsweise immer die spektrale Signatur des räumlichen Musters mehrerer der oben genannten Einflussgrößen, was die Extraktion oder Diskriminierung der eigentlich interessierenden Größe erschwert. Dieser „vermischte“ Charakter der Fernerkundungsdaten bietet aber auch immense Chancen. So lassen sich durch geeignete Interpretationsverfahren aus jedem mit hohem finanziellem und technischem Aufwand erstellten Satellitenbild zahlreiche und im Detail völlig unterschiedliche Fragestellungen bearbeiten. Die Extraktion der gewünschten Information aus dem Fernerkundungssignal führt mathematisch gesehen meist auf die Lösung so genannter inverser, schlecht gestellter Probleme. Somit beinhaltet die interdisziplinäre Nutzung von Fernerkundung auch ein hohes methodisches Synergiepotential. Durch die heutigen technischen Möglichkeiten zur Archivierung auch sehr umfangreicher raumbezogener Informationen ist die Bearbeitung zu jedem beliebigen Zeitpunkt nach der Aufnahme möglich – zum Beispiel bis entsprechend lange Zeitreihen und/oder geeignete Interpretationsverfahren zur Verfügung stehen. Tatsächlich dürfte der weitaus größte Teil der raumbezogenen Informationen, die in den bisher erhobenen Fernerkundungsdaten stecken, nur in Ansätzen ausgewertet sein. Einer bereits sehr hoch entwickelten technischen Dimension der Fernerkundung steht ein gewisses Defizit im Umfang ihrer Anwendung in den verschiedenen naturwissenschaftlichen Disziplinen gegenüber. Aktuelle und sehr drängende Fragen innerhalb dieses Forschungsschwerpunktes sind unter anderem: • Nutzung der räumlichen und inhaltlichen Breite von Fernerkundungsinformationen; • Verbindung mit automatisierten, u.a. geophysikalischen Methoden des „ground-truthings“; • Identifizierung der Grenzen bzgl. Repräsentanz der Daten (spektral, raum-zeitliche Auflösung); • Verbindung unterschiedlicher Methoden der Fernerkundung und der Geophysik. Dieser Beitrag illustriert die o.g. Fragestellungen anhand einiger Darstellungen aus verschiedenen wissenschaftlichen Disziplinen und erläutert 2 Beispiele zu beabsichtigten Forschungsprojekten: • Erfassung und Bedeutung von Boden-Oberflächeneigenschaften auf die Abflussbildung von Landschaften; • Phänomene des Stofftransportes in homogenen vs. heterogenen Böden. Y1 - 2006 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-7021 N1 - Dokument 1: Foliensatz | Dokument 2: Abstract | Dokumente 3 und 4: Animation Interdisziplinäres Zentrum für Musterdynamik und Angewandte Fernerkundung Workshop vom 9. - 10. Februar 2006 ER - TY - JOUR A1 - Hattermann, Fred Fokko A1 - Krysanova, Valentina A1 - Habeck, Anja A1 - Bronstert, Axel T1 - Integrating wetlands and riparian zones in river basin modelling JF - Ecological modelling : international journal on ecological modelling and engineering and systems ecolog N2 - Wetlands, and in particular riparian wetlands, represent an interface between the catchment area and the aquatic environment. They control the exchange of water and related chemical fluxes from the upper catchment area to surface waters like streams and lakes. Their influence on water and nutrient balances has been investigated mainly at the patch scale. In this study an attempt was made (a) to integrate riparian zones and wetlands into eco-hydrological river basin modelling, and (b) to quantify the impacts of riparian wetland processes on water and nutrient fluxes in a meso-scale catchment located in the northeastern German lowland. The investigation was performed by analysing hydro-chemical field data and applying the eco-hydrological model SWIM (Soil and Water Integrated Model), which was extended to reproduce the relevant water and nutrient flows and retention processes at the catchment scale in general, and in riparian zones and wetlands in particular. The main extensions introduced in the model were: (1) implementation of daily groundwater table dynamics at the hydrotope level, (2) implementation of water and nutrient uptake by plants from groundwater in riparian zones and wetlands, and (3) assessment of nutrient retention in groundwater and interflow. The simulation results indicate that wetlands, though they represent relatively small parts of the total catchment area, may have a significant impact on the overall water and nutrient balances of the catchment. The uncertainty of the simulation results is considerably high, with the main sources of uncertainty being the model parameters representing the geo-hydrology and the input data for land use management. (c) 2006 Elsevier B.V. All rights reserved. KW - riparian zones KW - wetlands KW - water quality KW - groundwater dynamics KW - nutrient retention KW - integrated river basin modelling Y1 - 2006 U6 - https://doi.org/10.1016/j.ecolmodel.2005.06.012 SN - 0304-3800 VL - 199 IS - 4 SP - 379 EP - 392 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Zehe, Erwin A1 - Gräff, Thomas A1 - Morgner, Markus A1 - Bauer, Andreas A1 - Bronstert, Axel T1 - Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains N2 - This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weißeritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a strong correlation between average soil moisture dynamics and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld, which explains almost as much variability in the runoff coefficients as pre-event discharge. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, long term simulations with a physically based hydrological model were in good/acceptable accordance with the time series of spatial average soil water content observed at the forested site and the grassland site, respectively. Both simulations used a homogeneous soil setup that closely reproduces observed average soil conditions observed at the field sites. This corroborates the proposed sampling strategy of clustering TDR probes in typical functional units is a promising technique to explore the soil moisture control on runoff generation. Long term monitoring of such sites could maybe yield valuable information for flood warning. The sampling strategy helps furthermore to unravel different types of soil moisture variability. Y1 - 2008 ER - TY - GEN A1 - Blume, Theresa A1 - Zehe, Erwin A1 - Bronstert, Axel T1 - Use of soil moisture dynamics and patterns at different spatio-temporal scales for the investigation of subsurface flow processes N2 - Spatial patterns as well as temporal dynamics of soil moisture have a major influence on runoff generation. The investigation of these dynamics and patterns can thus yield valuable information on hydrological processes, especially in data scarce or previously ungauged catchments. The combination of spatially scarce but temporally high resolution soil moisture profiles with episodic and thus temporally scarce moisture profiles at additional locations provides information on spatial as well as temporal patterns of soil moisture at the hillslope transect scale. This approach is better suited to difficult terrain (dense forest, steep slopes) than geophysical techniques and at the same time less cost-intensive than a high resolution grid of continuously measuring sensors. Rainfall simulation experiments with dye tracers while continuously monitoring soil moisture response allows for visualization of flow processes in the unsaturated zone at these locations. Data was analyzed at different spacio-temporal scales using various graphical methods, such as space-time colour maps (for the event and plot scale) and binary indicator maps (for the long-term and hillslope scale). Annual dynamics of soil moisture and decimeterscale variability were also investigated. The proposed approach proved to be successful in the investigation of flow processes in the unsaturated zone and showed the importance of preferential flow in the Malalcahuello Catchment, a datascarce catchment in the Andes of Southern Chile. Fast response times of stream flow indicate that preferential flow observed at the plot scale might also be of importance at the hillslope or catchment scale. Flow patterns were highly variable in space but persistent in time. The most likely explanation for preferential flow in this catchment is a combination of hydrophobicity, small scale heterogeneity in rainfall due to redistribution in the canopy and strong gradients in unsaturated conductivities leading to self-reinforcing flow paths. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - paper 125 KW - Repellent sandy soil KW - Poorly gauged catchment KW - Volcanic ash soils KW - Water repellency KW - Preferential flow Y1 - 2009 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus-44924 ER - TY - JOUR A1 - Medeiros, Pedro Henrique Augusto A1 - de Araujo, Jose Carlos A1 - Bronstert, Axel T1 - Interception measurements and assessment of Gash model performance for a tropical semi-arid region N2 - Semi-arid environments usually face water scarcity and conflicts for its use; therefore a complete understanding of the water balance in these regions is desired. To evaluate interception, measurements of precipitation, throughfall and stemflow were carried out in a Brazilian tropical semi-arid experimental watershed with well preserved Caatinga vegetation. Data analysis indicates that interception losses correspond to 13% of total rainfall, representing an important process in the watershed's water balance, where runoff is only 6% of total precipitation. Gash interception model was applied in the region with good results for long term simulation. Nevertheless, the model produced significant but not systematic errors on a daily basis. This was attributed to its incapability of representing the temporal variation of precipitation during the event, which is a major factor affecting interception. Rainfall intensity was shown to be a good parameter to determine an applicability threshold for Gash model in the study area. Y1 - 2009 SN - 0045-6888 ER - TY - JOUR A1 - Bronstert, Axel A1 - Kneis, David A1 - Bogena, Heye R. T1 - Interactions and feedbacks in hydrological change : relevance and possibilities of modelling N2 - The hydrological cycle is a dynamic system by its nature, but sometimes accelerated through anthropogenic activity. A "hydrological change" (i.e. a water cycle that is significantly changing over a longer period of time) can be very different in character, depending on the specific natural conditions and the underlying spatial and temporal scales. Such changes may affect the availability and quality of water as essential pre-requisites for human development and ecosystem stability. Hydrological extremes, such as floods and droughts, may also be affected, what is also vitally important, because of their profound economic and societal impacts. Anthropogenically induced hydrological change can be attributed to three main external causes: first, the Earth's climate is changing significantly and thus directly affecting the terrestrial hydro-systems via the exchange of energy and heat. The second major issue is the land cover and its management that has been modified fundamentally by conversion of land for agriculture, forestry, and other purposes such as industrialisation and urbanisation. Finally, water resources are being used more than ever for human development, especially for agriculture, industrial activities, and navigation. If the regional terrestrial hydrological cycle is changing and counter-measures are desirable, it is from a scientific perspective mandatory to understand the extent and nature of such changes, and, especially, to identify their possible anthropogenic origin. There are, however, fundamental gaps in our knowledge, in particular about the role of feedbacks between individual processes and compartments of the hydrological cycle or the relevance of the interactions with other sub-systems of our planet, such as the atmosphere or the vegetation. This paper mentions several examples of hydrological change and discusses their identification, interaction processes, and feedback mechanisms, along with modelling issues. The possibilities and limitations of modelling are demonstrated by means of two studies: one from the river-lake system on the Middle-Havel River and one from the catchment of the Wahnbach Reservoir. The applied model systems comprise a series of consecutively coupled individual models (so-called one-way-coupling). Model systems that are able reflect feedback effects (two-way- coupling) are still in the development stage. It became clear that the applied model systems were able to reproduce the observed dynamics of the hydrological cycle and of selected matter fluxes. However, one has to be aware that the simulated time periods and scenarios represent rather moderately transient conditions, what is the justification why the one-way-coupling seems to be applicable. Furthermore, it was shown that the modelling uncertainty is considerably large. Nevertheless, this uncertainty can be distinguished from effects of changed internal systems dynamics or from changed boundary conditions, what is a basis for the usability of such model systems for prognostic purposes. Y1 - 2009 SN - 1439-1783 ER - TY - JOUR A1 - Kneis, David A1 - Förster, Saskia A1 - Bronstert, Axel T1 - Simulation of water quality in a flood detention area using models of different spatial discretization N2 - Detention areas provide a means to lower peak discharges in rivers by temporarily storing excess water. In the case of extreme flood events, the storage effect reduces the risk of dike failures or extensive inundations for downstream reaches and near the site of abstraction. Due to the large amount of organic matter contained in the river water and the inundation of terrestrial vegetation in the detention area, a deterioration of water quality may occur. In particular, decay processes can cause a severe depletion of dissolved oxygen (DO) in the temporary water body. In this paper, we studied the potential of a water quality model to simulate the DO dynamics in a large but shallow detention area to be built at the Elbe River (Germany). Our focus was on examining the impact of spatial discretization on the model's performance and usability. Therefore, we used a zero-dimensional (OD) and a two-dimensional (2D) modeling approach in parallel. The two approaches solely differ in their spatial discretization, while conversion processes, parameters, and boundary conditions were kept identical. The dynamics of DO simulated by the two models are similar in the initial flooding period but diverge when the system starts to drain. The deviation can be attributed to the different spatial discretization of the two models, leading to different estimates of flow velocities and water depths. Only the 2D model can account for the impact of spatial variability on the evolution of state variables. However, its application requires high efforts for pre- and post-processing and significantly longer computation times. The 2D model is, therefore, not suitable for investigating various flood scenarios or for analyzing the impact of parameter uncertainty. For practical applications, we recommend to firstly set up a fast-running model of reduced spatial discretization, e.g. a OD model. Using this tool, the reliability of the simulation results should be checked by analyzing the parameter uncertainty of the water quality model. A particular focus may be on those parameters that are spatially variable and, therefore, believed to be better represented in a 2D approach. The benefit from the application of the more costly 2D model should be assessed, based on the analyses carried out with the OD model. A 2D model appears to be preferable only if the simulated detention area has a complex topography, flow velocities are highly variable in space, and the parameters of the water quality model are well known. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03043800 U6 - https://doi.org/10.1016/j.ecolmodel.2009.04.006 SN - 0304-3800 ER - TY - JOUR A1 - Bronstert, Axel A1 - Kneis, David A1 - Bogena, Heye R. T1 - Interaktionen und Rückkopplungen beim hydrologischen Wandel : Relevanz und Möglichkeiten der Modellierung Y1 - 2009 SN - 1439-1783 ER - TY - JOUR A1 - Breuer, Lutz A1 - Bormann, Helge A1 - Bronstert, Axel A1 - Croke, Barry F. W. A1 - Frede, Hans-Georg A1 - Gräff, Thomas A1 - Hubrechts, Lode A1 - Kite, Geoffrey A1 - Lanini, Jordan A1 - Leavesley, George A1 - Lettenmaier, Dennis P. A1 - Lindstroem, Goeran A1 - Seibert, Jan A1 - Sivapalan, Mayuran A1 - Viney, Neil R. A1 - Willems, Patrick T1 - Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM) III : scenario analysis N2 - An ensemble of 10 hydrological models was applied to the same set of land use change scenarios. There was general agreement about the direction of changes in the mean annual discharge and 90% discharge percentile predicted by the ensemble members, although a considerable range in the magnitude of predictions for the scenarios and catchments under consideration was obvious. Differences in the magnitude of the increase were attributed to the different mean annual actual evapotranspiration rates for each land use type. The ensemble of model runs was further analyzed with deterministic and probabilistic ensemble methods. The deterministic ensemble method based on a trimmed mean resulted in a single somewhat more reliable scenario prediction. The probabilistic reliability ensemble averaging (REA) method allowed a quantification of the model structure uncertainty in the scenario predictions. It was concluded that the use of a model ensemble has greatly increased our confidence in the reliability of the model predictions. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03091708 U6 - https://doi.org/10.1016/j.advwatres.2008.06.009 SN - 0309-1708 ER - TY - JOUR A1 - Viney, Neil R. A1 - Bormann, Helge A1 - Breuer, Lutz A1 - Bronstert, Axel A1 - Croke, Barry F. W. A1 - Frede, Hans-Georg A1 - Gräff, Thomas A1 - Hubrechts, Lode A1 - Huisman, Johan A. A1 - Jakeman, Anthony J. A1 - Kite, Geoffrey W. A1 - Lanini, Jordan A1 - Leavesley, George A1 - Lettenmaier, Dennis P. A1 - Lindstroem, Goeran A1 - Seibert, Jan A1 - Sivapalan, Murugesu A1 - Willems, Patrick T1 - Assessing the impact of land use change on hydrology by ensemble modelling (LUCHEM) II : ensemble combinations and predictions N2 - This paper reports on a project to compare predictions from a range of catchment models applied to a mesoscale river basin in central Germany and to assess various ensemble predictions of catchment streamflow. The models encompass a large range in inherent complexity and input requirements. In approximate order of decreasing complexity, they are DHSVM, MIKE-SHE, TOPLATS, WASIM-ETH, SWAT, PRMS, SLURP, HBV, LASCAM and IHACRES. The models are calibrated twice using different sets of input data. The two predictions from each model are then combined by simple averaging to produce a single-model ensemble. The 10 resulting single-model ensembles are combined in various ways to produce multi-model ensemble predictions. Both the single-model ensembles and the multi-model ensembles are shown to give predictions that are generally superior to those of their respective constituent models, both during a 7-year calibration period and a 9- year validation period. This occurs despite a considerable disparity in performance of the individual models. Even the weakest of models is shown to contribute useful information to the ensembles they are part of. The best model combination methods are a trimmed mean (constructed using the central four or six predictions each day) and a weighted mean ensemble (with weights calculated from calibration performance) that places relatively large weights on the better performing models. Conditional ensembles. in which separate model weights are used in different system states (e.g. summer and winter, high and low flows) generally yield little improvement over the weighted mean ensemble. However a conditional ensemble that discriminates between rising and receding flows shows moderate improvement. An analysis of ensemble predictions shows that the best ensembles are not necessarily those containing the best individual models. Conversely, it appears that some models that predict well individually do not necessarily combine well with other models in multi-model ensembles. The reasons behind these observations may relate to the effects of the weighting schemes, non- stationarity of the climate series and possible cross-correlations between models. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03091708 U6 - https://doi.org/10.1016/j.advwatres.2008.05.006 SN - 0309-1708 ER - TY - JOUR A1 - Breuer, Lutz A1 - Willems, Patrick A1 - Bormann, Helge A1 - Bronstert, Axel A1 - Croke, Barry A1 - Frede, Hans Georg A1 - Gräff, Thomas A1 - Hubrechts, Lode A1 - Kite, Geoffrey A1 - Lanini, Jordan A1 - Leavesley, George A1 - Lettenmaier, Dennis P. A1 - Lindstroem, Goeran A1 - Seibert, Jan A1 - Sivapalan, Mayuran A1 - Viney, Neil R. T1 - Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM) : I: model intercomparison with current land use N2 - This paper introduces the project on 'Assessing the impact of land use change on hydrology by ensemble modeling (LUCHEM)' that aims at investigating the envelope of predictions on changes in hydrological fluxes due to land use change. As part of a series of four papers, this paper outlines the motivation and setup of LUCHEM, and presents a model intercomparison for the present-day simulation results. Such an intercomparison provides a valuable basis to investigate the effects of different model structures on model predictions and paves the ground for the analysis of the performance of multi-model ensembles and the reliability of the scenario predictions in companion papers. in this study, we applied a set of 10 lumped, semi-lumped and fully distributed hydrological models that have been previously used in land use change studies to the low mountainous Dill catchment. Germany. Substantial differences in model performance were observed with Nash-Sutcliffe efficiencies ranging from 0.53 to 0.92. Differences in model performance were attributed to (1) model input data, (2) model calibration and (3) the physical basis of the models. The models were applied with two sets of input data: an original and a homogenized data set. This homogenization of precipitation, temperature and leaf area index was performed to reduce the variation between the models. Homogenization improved the comparability of model simulations and resulted in a reduced average bias, although some variation in model data input remained. The effect of the physical differences between models on the long-term water balance was mainly attributed to differences in how models represent evapotranspiration. Semi-lumped and lumped conceptual models slightly outperformed the fully distributed and physically based models. This was attributed to the automatic model calibration typically used for this type of models. Overall, however, we conclude that there was no superior model if several measures of model performance are considered and that all models are suitable to participate in further multi-model ensemble set-ups and land use change scenario investigations. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03091708 U6 - https://doi.org/10.1016/j.advwatres.2008.10.003 SN - 0309-1708 ER - TY - JOUR A1 - Gräff, Thomas A1 - Zehe, Erwin A1 - Reusser, Dominik A1 - Lueck, Erika A1 - Schroeder, Boris A1 - Wenk, Gerald A1 - John, Hermann A1 - Bronstert, Axel T1 - Process identification through rejection of model structures in a mid-mountainous rural catchment : observations of rainfall-runoff response, geophysical conditions and model inter-comparison N2 - The intention of the presented study is to gain a better understanding of the mechanisms that caused the bimodal rainfall-runoff responses which occurred up to the mid-1970s regularly in the Schafertal catchment and vanished after the onset of mining activities. Understanding, this process is a first step to understanding the ongoing hydrological change in this area. It is hypothesized that either subsurface stormflow, or fast displacement of groundwater, could cause the second delayed peak. A top-down analysis of rainfall-runoff data, field observations as well as process modelling are combined within a rejectionistic framework. A statistical analysis is used to test whether different predictors. which characterize the forcing. near surface water content and deeper subsurface store, allow the prediction of the type of rainfall-runoff response. Regression analysis is used with generalized linear models Lis they can deal with non-Gaussian error distributions Lis well its a non-stationary variance. The analysis reveals that the dominant predictors are the pre-event discharge (proxy of state of the groundwater store) and the precipitation amount, In the field campaign, the subsurface at a representative hillslope was investigated by means of electrical resistivity tomography in order to identify possible strata as flow paths for subsurface stormflow. A low resistivity in approximately 4 in depth-either due to a less permeable layer or the groundwater surface-was detected. The former Could serve as a flow path for subsurface stormflow. Finally, the physical-based hydrological model CATFLOW and the groundwater model FEFLOW are compared with respect to their ability to reproduce the bimodal runoff responses. The groundwater model is able to reproduce the observations, although it uses only an abstract representation of the hillslopes. Process model analysis as well Lis statistical analysis strongly suggest that fast displacement of groundwater is the dominant process underlying the bimodal runoff reactions. Y1 - 2009 UR - http://www3.interscience.wiley.com/journal/4125/home U6 - https://doi.org/10.1002/Hyp.7171 SN - 0885-6087 ER - TY - JOUR A1 - Müller, Eva Nora A1 - Francke, Till A1 - Batalla Villanueva, Ramon J. A1 - Bronstert, Axel T1 - Modelling the effects of land-use change on runoff and sediment yield for a meso-scale catchment in the Southern Pyrenees N2 - The Southern Pre-Pyrenees experienced a substantial land-use change over the second half of the 20th century owing to the reduction of agricultural activities towards the formation of a more natural forest landscape. The land-use change over the last 50 years with subsequent effects on water and sediment export was modelled with the process-based, spatially semi-distributed WASA-SED model for the meso-scale Canalda catchment in Catalonia, Spain. It was forwarded that the model yielded plausible results for runoff and sediment yield dynamics without the need of calibration, although the model failed to reproduce the shape of the hydrograph and the total discharge of several individual rainstorm events, hence the simulation capabilities are not yet considered sufficient for decision-making purposes for land management. As there are only a very limited amount of measured data available on sediment budgets with altered land-use and climate change settings, the WASA-SED model was used to obtain qualitative estimates on the effects of past and future change scenarios to derive a baseline for hypothesis building and future discussion on the evolution of sediment budgets in such a dryland setting. Simulating the effects of the past land-use change, the model scenarios resulted in a decrease of up to 75% of the annual sediment yield. whereas modelled runoff remained almost constant over the last 50 years. The relative importance of environmental change was evaluated by comparing the impact on sediment export of land-use change, that are driven by socio-economic factors, with climate change projections for changes in the rainfall regime. The modelling results suggest that a 20% decrease in annual rainfall results in a decrease in runoff and sediment yield, thus an ecosystem stabilisation in regard to sediment export which can only be achieved by a substantial land-use change equivalent to a complete afforestation. At the same time, a 20% increase in rainfall causes a large export of water and sediment resources out of the catchment, equivalent to an intensive agricultural use of 100% of the catchment area. For wet years, the effects of agricultural intensification are more pronounced, so that in this case the intensive land-use change has a significantly larger impact on sediment generation than climate change. The WASA-SED model proved capable in quantifying the impacts of actual and potential environmental change, but the reliability of the simulation results is still circumscribed by considerable parameterisation and model uncertainties. Y1 - 2009 UR - http://www.sciencedirect.com/science/journal/03418162 U6 - https://doi.org/10.1016/j.catena.2009.06.007 SN - 0341-8162 ER - TY - JOUR A1 - Zehe, Erwin A1 - Gräff, Thomas A1 - Morgner, Markus A1 - Bauer, Andreas A1 - Bronstert, Axel T1 - Plot and field scale soil moisture dynamics and subsurface wetness control on runoff generation in a headwater in the Ore Mountains N2 - This study presents an application of an innovative sampling strategy to assess soil moisture dynamics in a headwater of the Weisseritz in the German eastern Ore Mountains. A grassland site and a forested site were instrumented with two Spatial TDR clusters (STDR) that consist of 39 and 32 coated TDR probes of 60 cm length. Distributed time series of vertically averaged soil moisture data from both sites/ensembles were analyzed by statistical and geostatistical methods. Spatial variability and the spatial mean at the forested site were larger than at the grassland site. Furthermore, clustering of TDR probes in combination with long-term monitoring allowed identification of average spatial covariance structures at the small field scale for different wetness states. The correlation length of soil water content as well as the sill to nugget ratio at the grassland site increased with increasing average wetness and but, in contrast, were constant at the forested site. As soil properties at both the forested and grassland sites are extremely variable, this suggests that the correlation structure at the forested site is dominated by the pattern of throughfall and interception. We also found a very strong correlation between antecedent soil moisture at the forested site and runoff coefficients of rainfall-runoff events observed at gauge Rehefeld. Antecedent soil moisture at the forest site explains 92% of the variability in the runoff coefficients. By combining these results with a recession analysis we derived a first conceptual model of the dominant runoff mechanisms operating in this catchment. Finally, we employed a physically based hydrological model to shed light on the controls of soil- and plant morphological parameters on soil average soil moisture at the forested site and the grassland site, respectively. A homogeneous soil setup allowed, after fine tuning of plant morphological parameters, most of the time unbiased predictions of the observed average soil conditions observed at both field sites. We conclude that the proposed sampling strategy of clustering TDR probes is suitable to assess unbiased average soil moisture dynamics in critical functional units, in this case the forested site, which is a much better predictor for event scale runoff formation than pre-event discharge. Long term monitoring of such critical landscape elements could maybe yield valuable information for flood warning in headwaters. We thus think that STDR provides a good intersect of the advantages of permanent sampling and spatially highly resolved soil moisture sampling using mobile rods. Y1 - 2010 UR - http://www.copernicus.org/EGU/hess/hess.html U6 - https://doi.org/10.5194/hess-14-873-2010 SN - 1027-5606 ER - TY - JOUR A1 - Gräff, Thomas A1 - Zehe, Erwin A1 - Schläger, Stefan A1 - Morgner, Markus A1 - Bauer, Andreas A1 - Becker, Rolf A1 - Creutzfeldt, Benjamin A1 - Bronstert, Axel T1 - A quality assessment of spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments N2 - Investigation of transient soil moisture profiles yields valuable information of near- surface processes. A recently developed reconstruction algorithm based on the telegraph equation allows the inverse estimation of soil moisture profiles along coated, three rod TDR probes. Laboratory experiments were carried out to prove the results of the inversion and to understand the influence of probe rod deformation and solid objects close to the probe in heterogonous media. Differences in rod geometry can lead to serious misinterpretations in the soil moisture profile but have small influence on the average soil moisture along the probe. Solids in the integration volume have almost no effect on average soil moisture but result in locally slightly decreased moisture values. Inverted profiles obtained in a loamy soil with a clay content of about 16% were in good agreement with independent measurements. Y1 - 2010 UR - http://www.hydrol-earth-syst-sci-discuss.net/volumes_and_issues.html U6 - https://doi.org/10.5194/hessd-7-269-2010 SN - 1812-2108 ER - TY - JOUR A1 - Gräff, Thomas A1 - Zehe, Erwin A1 - Schlaeger, Stefan A1 - Morgner, Markus A1 - Bauer, Andreas A1 - Becker, Rolf A1 - Creutzfeldt, Benjamin A1 - Bronstert, Axel T1 - A quality assessment of Spatial TDR soil moisture measurements in homogenous and heterogeneous media with laboratory experiments N2 - Investigation of transient soil moisture profiles yields valuable information of near- surface processes. A recently developed reconstruction algorithm based on the telegraph equation allows the inverse estimation of soil moisture profiles along coated, three rod TDR probes. Laboratory experiments were carried out to prove the results of the inversion and to understand the influence of probe rod deformation and solid objects close to the probe in heterogeneous media. Differences in rod geometry can lead to serious misinterpretations in the soil moisture profile, but have small influence on the average soil moisture along the probe. Solids in the integration volume have almost no effect on average soil moisture, but result in locally slightly decreased moisture values. Inverted profiles obtained in a loamy soil with a clay content of about 16% were in good agreement with independent measurements. Y1 - 2010 UR - http://www.copernicus.org/EGU/hess/hess.html U6 - https://doi.org/10.5194/hess-14-1007-2010 SN - 1027-5606 ER - TY - JOUR A1 - Iroume, Andres A1 - Carey, Patricio A1 - Bronstert, Axel A1 - Huber, Anton A1 - Palacios, Hardin T1 - GIS application of USLE and MUSLE to estimate erosion and suspended sediment load in experimental catchments, Valdivia, Chile JF - Revista técnica de la Facultad de Ingenieria N2 - This paper presents the results of a research aimed to quantify suspended sediment transport in three experimental catchments in southern Chile, to compare measured suspended sediment load with estimated erosion using the Universal Soil Loss Equation (USLE) applied in a GIS environment and to validate de Modified Universal Soil Loss Equation (MUSLE) used to estimate suspended sediment loads from forest catchments. The catchments are Los Pinos (94.2 ha), Los Ulmos 1 (12.6 ha) and Los Ulmos 2 (17.7 ha). Soil losses estimated with USLE for the three catchments are higher than those measured in runoff experimental lots under bare soil conditions, which could indicate an overestimation of the LS calculated in GIS and the fact that the USLE model does not compute sediment deposit and storage within the catchment. A statistical significant relation was found between measured and estimated (MUSLE) suspended sediment load, which would indicate that this model could be applied to estimate suspended sediment load from small catchments in southern Chile. KW - suspended sediments KW - USLE KW - MUSLE KW - experimental catchments Y1 - 2011 SN - 0254-0770 VL - 34 IS - 2 SP - 119 EP - 128 PB - Facultad de Ingenieria Universidad del Zulia CY - Maracaibo ER - TY - JOUR A1 - Costa, A. C. A1 - Bronstert, Axel A1 - de Araujo, Jose Carlos T1 - A channel transmission losses model for different dryland rivers JF - Hydrology and earth system sciences : HESS N2 - Channel transmission losses in drylands take place normally in extensive alluvial channels or streambeds underlain by fractured rocks. They can play an important role in streamflow rates, groundwater recharge, freshwater supply and channel-associated ecosystems. We aim to develop a process-oriented, semi-distributed channel transmission losses model, using process formulations which are suitable for data-scarce dryland environments and applicable to both hydraulically disconnected losing streams and hydraulically connected losing(/gaining) streams. This approach should be able to cover a large variation in climate and hydro-geologic controls, which are typically found in dryland regions of the Earth. Our model was first evaluated for a losing/gaining, hydraulically connected 30 km reach of the Middle Jaguaribe River (MJR), Ceara, Brazil, which drains a catchment area of 20 000 km(2). Secondly, we applied it to a small losing, hydraulically disconnected 1.5 km channel reach in the Walnut Gulch Experimental Watershed (WGEW), Arizona, USA. The model was able to predict reliably the streamflow volume and peak for both case studies without using any parameter calibration procedure. We have shown that the evaluation of the hypotheses on the dominant hydrological processes was fundamental for reducing structural model uncertainties and improving the streamflow prediction. For instance, in the case of the large river reach (MJR), it was shown that both lateral stream-aquifer water fluxes and groundwater flow in the underlying alluvium parallel to the river course are necessary to predict streamflow volume and channel transmission losses, the former process being more relevant than the latter. Regarding model uncertainty, it was shown that the approaches, which were applied for the unsaturated zone processes (highly nonlinear with elaborate numerical solutions), are much more sensitive to parameter variability than those approaches which were used for the saturated zone (mathematically simple water budgeting in aquifer columns, including backwater effects). In case of the MJR-application, we have seen that structural uncertainties due to the limited knowledge of the subsurface saturated system interactions (i.e. groundwater coupling with channel water; possible groundwater flow parallel to the river) were more relevant than those related to the subsurface parameter variability. In case of the WEGW application we have seen that the non-linearity involved in the unsaturated flow processes in disconnected dryland river systems (controlled by the unsaturated zone) generally contain far more model uncertainties than do connected systems controlled by the saturated flow. Therefore, the degree of aridity of a dryland river may be an indicator of potential model uncertainty and subsequent attainable predictability of the system. Y1 - 2012 U6 - https://doi.org/10.5194/hess-16-1111-2012 SN - 1027-5606 VL - 16 IS - 4 SP - 1111 EP - 1135 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Kneis, David A1 - Buerger, Gerd A1 - Bronstert, Axel T1 - Evaluation of medium-range runoff forecasts for a 50 km(2) watershed JF - Journal of hydrology N2 - We generated medium-range forecasts of runoff for a 50 km(2) headwater catchment upstream of a reservoir using numerical weather predictions (NWPs) of the past as input to an operational hydrological model. NWP data originating from different sources were tested. For a period of 8.5 years, we computed daily forecasts with a lead time of +120 h based on an empirically downscaled version of the ECMWF's ensemble prediction system. For the last 3.5 years of the test period, we also tried the deterministic COSMO-EU forecast disseminated by the German Weather Service for lead times of up to +72 h. Common measures of skill indicate superiority of the ensemble runoff forecast over single-value forecasts for longer lead times. However, regardless of which NWP data were being used, the probability of event detection (POD) was found to be generally lower than 50%. In many cases, values in the range of 20-30% were obtained. At the same time, the false alarms ratio (FAR) was often found to be considerably high. The observed uncertainties in the hydrological forecasts were shown to originate from both the insufficient quality of precipitation forecasts as well as deficiencies in hydrological modeling and quantitative precipitation estimation. With respect to the anticipatory control of reservoirs in the studied catchment, the value of the tested runoff forecasts appears to be limited. This is due to the unfavorably low POD/FAR ratio in conjunction with a high cost-loss ratio. However, our results indicate that, in many cases, major runoff events related to snow melt can be successfully predicted as early as 4-5 days in advance. KW - Runoff forecast KW - Small catchments KW - Forecast verification KW - Reservoir control Y1 - 2012 U6 - https://doi.org/10.1016/j.jhydrol.2011.11.005 SN - 0022-1694 VL - 414 IS - 2 SP - 341 EP - 353 PB - Elsevier CY - Amsterdam ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Montgomery, David R. A1 - Huber, Anton A1 - Bronstert, Axel A1 - Iroume, Andres T1 - Streamflow response in small upland catchments in the Chilean coastal range to the M-W 8.8 Maule earthquake on 27 February 2010 JF - Journal of geophysical research : Earth surface N2 - Hydrological response to earthquakes has long been observed, yet the mechanisms responsible still remain unclear and likely vary in space and time. This study explores the base flow response in small upland catchments of the Coastal Range of south-central Chile after the M-W 8.8 Maule earthquake of 27 February 2010. An initial decline in streamflow followed by an increase of up to 400% of the discharge measured immediately before the earthquake occurred, and diurnal streamflow oscillations intensified after the earthquake. Neither response time, nor time to maximum streamflow discharge showed any relationship with catchment topography or size, suggesting non-uniform release of water across the catchments. The fast response, unaffected stream water temperatures and a simple diffusion model point to the sandy saprolite as the source of the excess water. Base flow recession analysis reveals no evidence for substantial enhancement of lateral hydraulic conductivity in the saprolite after the earthquake. Seismic energy density reached similar to 170 J/m(3) for the main shock and similar to 0.9 J/m(3) for the aftershock, exceeding the threshold for liquefaction by undrained consolidation only during the main shock. Although increased hydraulic gradient due to ground acceleration-triggered, undrained consolidation is consistent with empirical magnitude-distance relationships for liquefaction, the lack of independent evidence for liquefaction means that enhanced vertical permeability (probably in combination with co-seismic near-surface dilatancy) cannot be excluded as a potential mechanism. Undrained consolidation may have released additional water from the saturated saprolite into the overlying soil, temporarily reducing water transfer to the creeks but enlarging the cross-section of the saturated zone, which in turn enhanced streamflow after establishment of a new hydraulic equilibrium. The enlarged saturated zone facilitated water uptake by roots and intensified evapotranspiration. Y1 - 2012 U6 - https://doi.org/10.1029/2011JF002138 SN - 0148-0227 VL - 117 IS - 23 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Costa, Alexandre Cunha A1 - Bronstert, Axel A1 - Kneis, David T1 - Probabilistic flood forecasting for a mountainous headwater catchment using a nonparametric stochastic dynamic approach JF - Hydrological sciences journal = Journal des sciences hydrologiques N2 - Hydrological models are commonly used to perform real-time runoff forecasting for flood warning. Their application requires catchment characteristics and precipitation series that are not always available. An alternative approach is nonparametric modelling based only on runoff series. However, the following questions arise: Can nonparametric models show reliable forecasting? Can they perform as reliably as hydrological models? We performed probabilistic forecasting one, two and three hours ahead for a runoff series, with the aim of ascribing a probability density function to predicted discharge using time series analysis based on stochastic dynamics theory. The derived dynamic terms were compared to a hydrological model, LARSIM. Our procedure was able to forecast within 95% confidence interval 1-, 2- and 3-h ahead discharge probability functions with about 1.40 m(3)/s of range and relative errors (%) in the range [-30; 30]. The LARSIM model and the best nonparametric approaches gave similar results, but the range of relative errors was larger for the nonparametric approaches. KW - streamflow probabilistic forecasting KW - time series analysis KW - stochastic dynamical systems KW - parametric and nonparametric comparison Y1 - 2012 U6 - https://doi.org/10.1080/02626667.2011.637043 SN - 0262-6667 VL - 57 IS - 1 SP - 10 EP - 25 PB - Routledge, Taylor & Francis Group CY - Abingdon ER - TY - JOUR A1 - Bronstert, Axel A1 - Creutzfeldt, Benjamin A1 - Gräff, Thomas A1 - Hajnsek, Irena A1 - Heistermann, Maik A1 - Itzerott, Sibylle A1 - Jagdhuber, Thomas A1 - Kneis, David A1 - Lueck, Erika A1 - Reusser, Dominik A1 - Zehe, Erwin T1 - Potentials and constraints of different types of soil moisture observations for flood simulations in headwater catchments JF - Natural hazards : journal of the International Society for the Prevention and Mitigation of Natural Hazards N2 - Flood generation in mountainous headwater catchments is governed by rainfall intensities, by the spatial distribution of rainfall and by the state of the catchment prior to the rainfall, e. g. by the spatial pattern of the soil moisture, groundwater conditions and possibly snow. The work presented here explores the limits and potentials of measuring soil moisture with different methods and in different scales and their potential use for flood simulation. These measurements were obtained in 2007 and 2008 within a comprehensive multi-scale experiment in the Weisseritz headwater catchment in the Ore-Mountains, Germany. The following technologies have been applied jointly thermogravimetric method, frequency domain reflectometry (FDR) sensors, spatial time domain reflectometry (STDR) cluster, ground-penetrating radar (GPR), airborne polarimetric synthetic aperture radar (polarimetric SAR) and advanced synthetic aperture radar (ASAR) based on the satellite Envisat. We present exemplary soil measurement results, with spatial scales ranging from point scale, via hillslope and field scale, to the catchment scale. Only the spatial TDR cluster was able to record continuous data. The other methods are limited to the date of over-flights (airplane and satellite) or measurement campaigns on the ground. For possible use in flood simulation, the observation of soil moisture at multiple scales has to be combined with suitable hydrological modelling, using the hydrological model WaSiM-ETH. Therefore, several simulation experiments have been conducted in order to test both the usability of the recorded soil moisture data and the suitability of a distributed hydrological model to make use of this information. The measurement results show that airborne-based and satellite-based systems in particular provide information on the near-surface spatial distribution. However, there are still a variety of limitations, such as the need for parallel ground measurements (Envisat ASAR), uncertainties in polarimetric decomposition techniques (polarimetric SAR), very limited information from remote sensing methods about vegetated surfaces and the non-availability of continuous measurements. The model experiments showed the importance of soil moisture as an initial condition for physically based flood modelling. However, the observed moisture data reflect the surface or near-surface soil moisture only. Hence, only saturated overland flow might be related to these data. Other flood generation processes influenced by catchment wetness in the subsurface such as subsurface storm flow or quick groundwater drainage cannot be assessed by these data. One has to acknowledge that, in spite of innovative measuring techniques on all spatial scales, soil moisture data for entire vegetated catchments are still today not operationally available. Therefore, observations of soil moisture should primarily be used to improve the quality of continuous, distributed hydrological catchment models that simulate the spatial distribution of moisture internally. Thus, when and where soil moisture data are available, they should be compared with their simulated equivalents in order to improve the parameter estimates and possibly the structure of the hydrological model. KW - Soil moisture KW - Remote sensing KW - Hydrological modelling KW - Flood forecasting KW - Soil moisture measurement comparison Y1 - 2012 U6 - https://doi.org/10.1007/s11069-011-9874-9 SN - 0921-030X SN - 1573-0840 VL - 60 IS - 3 SP - 879 EP - 914 PB - Springer CY - New York ER - TY - JOUR A1 - Salazar, S. A1 - Frances, F. A1 - Komma, J. A1 - Blume, Theresa A1 - Francke, Till A1 - Bronstert, Axel A1 - Blöschl, Günter T1 - A comparative analysis of the effectiveness of flood management measures based on the concept of "retaining water in the landscape" in different European hydro-climatic regions JF - Natural hazards and earth system sciences N2 - In this paper, we analyse the effectiveness of flood management measures based on the concept known as "retaining water in the landscape". The investigated measures include afforestation, micro-ponds and small-reservoirs. A comparative and model-based methodological approach has been developed and applied for three meso-scale catchments located in different European hydro-climatological regions: Poyo (184 km(2)) in the Spanish Mediterranean, Upper Iller (954 km(2)) in the German Alps and Kamp (621 km(2)) in Northeast-Austria representing the Continental hydro-climate. This comparative analysis has found general similarities in spite of the particular differences among studied areas. In general terms, the flood reduction through the concept of "retaining water in the landscape" depends on the following factors: the storage capacity increase in the catchment resulting from such measures, the characteristics of the rainfall event, the antecedent soil moisture condition and the spatial distribution of such flood management measures in the catchment. In general, our study has shown that, this concept is effective for small and medium events, but almost negligible for the largest and less frequent floods: this holds true for all different hydro-climatic regions, and with different land-use, soils and morphological settings. Y1 - 2012 U6 - https://doi.org/10.5194/nhess-12-3287-2012 SN - 1561-8633 VL - 12 IS - 11 SP - 3287 EP - 3306 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Huang, Shaochun A1 - Hattermann, Fred Fokko A1 - Krysanova, Valentina A1 - Bronstert, Axel T1 - Projections of climate change impacts on river flood conditions in Germany by combining three different RCMs with a regional eco-hydrological model JF - Climatic change : an interdisciplinary, intern. journal devoted to the description, causes and implications of climatic change N2 - A general increase in precipitation has been observed in Germany in the last century, and potential changes in flood generation and intensity are now at the focus of interest. The aim of the paper is twofold: a) to project the future flood conditions in Germany accounting for various river regimes (from pluvial to nival-pluvial regimes) and under different climate scenarios (the high, A2, low, B1, and medium, A1B, emission scenarios) and b) to investigate sources of uncertainty generated by climate input data and regional climate models. Data of two dynamical Regional Climate Models (RCMs), REMO (REgional Model) and CCLM (Cosmo-Climate Local Model), and one statistical-empirical RCM, Wettreg (Wetterlagenbasierte Regionalisierungsmethode: weather-type based regionalization method), were applied to drive the eco-hydrological model SWIM (Soil and Water Integrated Model), which was previously validated for 15 gauges in Germany. At most of the gauges, the 95 and 99 percentiles of the simulated discharge using SWIM with observed climate data had a good agreement with the observed discharge for 1961-2000 (deviation within +/- 10 %). However, the simulated discharge had a bias when using RCM climate as input for the same period. Generalized Extreme Value (GEV) distributions were fitted to the annual maximum series of river runoff for each realization for the control and scenario periods, and the changes in flood generation over the whole simulation time were analyzed. The 50-year flood values estimated for two scenario periods (2021-2060, 2061-2100) were compared to the ones derived from the control period using the same climate models. The results driven by the statistical-empirical model show a declining trend in the flood level for most rivers, and under all climate scenarios. The simulations driven by dynamical models give various change directions depending on region, scenario and time period. The uncertainty in estimating high flows and, in particular, extreme floods remains high, due to differences in regional climate models, emission scenarios and multi-realizations generated by RCMs. Y1 - 2013 U6 - https://doi.org/10.1007/s10584-012-0586-2 SN - 0165-0009 SN - 1573-1480 VL - 116 IS - 3-4 SP - 631 EP - 663 PB - Springer CY - Dordrecht ER - TY - JOUR A1 - Jagdhuber, Thomas A1 - Hajnsek, Irena A1 - Bronstert, Axel A1 - Papathanassiou, Konstantinos Panagiotis T1 - Soil moisture estimation under low vegetation cover using a multi-angular polarimetric decomposition JF - IEEE transactions on geoscience and remote sensing N2 - The estimation of volumetric soil moisture under low agricultural vegetation from fully polarimetric synthetic aperture radar (SAR) data at L-band using a multi-angular polarimetric decomposition is investigated. Radar polarimetry provides the framework to decompose the backscattered signal into different canonical scattering mechanisms referring to scattering contributions from the underlying soil and the vegetation cover. Multiangular observation diversity further increases the information space for soil moisture inversion enabling higher inversion rates and a stable inversion performance. The developed approach was applied on the multi-angular L-band data set acquired by German Aerospace Center's ESAR sensor as part of the OPAQUE campaign in 2008. The obtained results are compared against ground measurements collected by the OPAQUE team over a variety of vegetated agricultural fields. The validation of the estimated against ground measured soil moisture results in an root mean square error level of 6-8 vol.% including all test fields with a variety of crop types. KW - Multi-angular model-based decomposition KW - polarimetric SAR KW - soil moisture Y1 - 2013 U6 - https://doi.org/10.1109/TGRS.2012.2209433 SN - 0196-2892 VL - 51 IS - 4 SP - 2201 EP - 2215 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER - TY - JOUR A1 - Costa, Alexandre Cunha A1 - Förster, Saskia A1 - de Araujo, Jose Carlos A1 - Bronstert, Axel T1 - Analysis of channel transmission losses in a dryland river reach in north-eastern Brazil using streamflow series, groundwater level series and multi-temporal satellite data JF - Hydrological processes N2 - Scarcity of hydrological data, especially streamflow discharge and groundwater level series, restricts the understanding of channel transmission losses (TL) in drylands. Furthermore, the lack of information on spatial river dynamics encompasses high uncertainty on TL analysis in large rivers. The objective of this study was to combine the information from streamflow and groundwater level series with multi-temporal satellite data to derive a hydrological concept of TL for a reach of the Middle Jaguaribe River (MJR) in semi-arid north-eastern Brazil. Based on this analysis, we proposed strategies for its modelling and simulation. TL take place in an alluvium, where river and groundwater can be considered to be hydraulically connected. Most losses certainly infiltrated only through streambed and levees and not through the flood plains, as could be shown by satellite image analysis. TL events whose input river flows were smaller than a threshold did not reach the outlet of the MJR. TL events whose input flows were higher than this threshold reached the outlet losing on average 30% of their input. During the dry seasons (DS) and at the beginning of rainy seasons (DS/BRS), no river flow is expected for pre-events, and events have vertical infiltration into the alluvium. At the middle and the end of the rainy seasons (MRS/ERS), river flow sustained by base flow occurs before/after events, and lateral infiltration into the alluvium plays a major role. Thus, the MJR shifts from being a losing river at DS/BRS to become a losing/gaining (mostly losing) river at MRS/ERS. A model of this system has to include the coupling of river and groundwater flow processes linked by a leakage approach. KW - channel transmission losses KW - multi-temporal RapidEye satellite data KW - semi-arid hydrology KW - north-eastern Brazil KW - dryland rivers KW - riveraquifer interaction Y1 - 2013 U6 - https://doi.org/10.1002/hyp.9243 SN - 1099-1085 VL - 27 IS - 7 SP - 1046 EP - 1060 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Coppus, Ruben A1 - Iroume, Andres A1 - Huber, Anton A1 - Bronstert, Axel T1 - Runoff generation and soil erosion processes after clear cutting JF - Journal of geophysical research : Earth surface N2 - Timber harvesting by clear cutting is known to impose environmental impacts, including severe disturbance of the soil hydraulic properties which intensify the frequency and magnitude of surface runoff and soil erosion. However, it remains unanswered if harvest areas act as sources or sinks for runoff and soil erosion and whether such behavior operates in a steady state or evolves through time. For this purpose, 92 small-scale rainfall simulations of different intensities were carried out under pine plantation conditions and on two clear-cut harvest areas of different age. Nonparametrical Random Forest statistical models were set up to quantify the impact of environmental variables on the hydrological and erosion response. Regardless of the applied rainfall intensity, runoff always initiated first and yielded most under plantation cover. Counter to expectations, infiltration rates increased after logging activities. Once a threshold rainfall intensity of 20mm/h was exceeded, the younger harvest area started to act as a source for both runoff and erosion after connectivity was established, whereas it remained a sink under lower applied rainfall intensities. The results suggest that the impact of microtopography on surface runoff connectivity and water-repellent properties of the topsoil act as first-order controls for the hydrological and erosion processes in such environments. Fast rainfall-runoff response, sediment-discharge-hystereses, and enhanced postlogging groundwater recharge at catchment scale support our interpretation. At the end, we show the need to account for nonstationary hydrological and erosional behavior of harvest areas, a fact previously unappreciated in predictive models. KW - infiltration KW - runoff KW - erosion KW - connectivity KW - rainfall simulation KW - catchment Y1 - 2013 U6 - https://doi.org/10.1002/jgrf.20047 SN - 2169-9003 VL - 118 IS - 2 SP - 814 EP - 831 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Conradt, Tobias A1 - Wechsung, F. A1 - Bronstert, Axel T1 - Three perceptions of the evapotranspiration landscape comparing spatial patterns from a distributed hydrological model, remotely sensed surface temperatures, and sub-basin water balances JF - Hydrology and earth system sciences : HESS N2 - A problem encountered by many distributed hydrological modelling studies is high simulation errors at interior gauges when the model is only globally calibrated at the outlet. We simulated river runoff in the Elbe River basin in central Europe (148 268 km(2)) with the semi-distributed eco-hydrological model SWIM (Soil and Water Integrated Model). While global parameter optimisation led to Nash-Sutcliffe efficiencies of 0.9 at the main outlet gauge, comparisons with measured runoff series at interior points revealed large deviations. Therefore, we compared three different strategies for deriving sub-basin evapotranspiration: (1) modelled by SWIM without any spatial calibration, (2) derived from remotely sensed surface temperatures, and (3) calculated from long-term precipitation and discharge data. The results show certain consistencies between the modelled and the remote sensing based evapotranspiration rates, but there seems to be no correlation between remote sensing and water balance based estimations. Subsequent analyses for single sub-basins identify amongst others input weather data and systematic error amplification in inter-gauge discharge calculations as sources of uncertainty. The results encourage careful utilisation of different data sources for enhancements in distributed hydrological modelling. Y1 - 2013 U6 - https://doi.org/10.5194/hess-17-2947-2013 SN - 1027-5606 VL - 17 IS - 7 SP - 2947 EP - 2966 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Heistermann, Maik A1 - Crisologo, Irene A1 - Abon, Catherine Cristobal A1 - Racoma, B. A. A1 - Jacobi, S. A1 - Servando, N. T. A1 - David, C. P. C. A1 - Bronstert, Axel T1 - Using the new Philippine radar network to reconstruct the Habagat of August 2012 monsoon event around Metropolitan Manila JF - Natural hazards and earth system sciences N2 - From 6 to 9 August 2012, intense rainfall hit the northern Philippines, causing massive floods in Metropolitan Manila and nearby regions. Local rain gauges recorded almost 1000mm within this period. However, the recently installed Philippine network of weather radars suggests that Metropolitan Manila might have escaped a potentially bigger flood just by a whisker, since the centre of mass of accumulated rainfall was located over Manila Bay. A shift of this centre by no more than 20 km could have resulted in a flood disaster far worse than what occurred during Typhoon Ketsana in September 2009. Y1 - 2013 U6 - https://doi.org/10.5194/nhess-13-653-2013 SN - 1561-8633 VL - 13 IS - 3 SP - 653 EP - 657 PB - Copernicus CY - Göttingen ER - TY - INPR A1 - de Araujo, Jose Carlos A1 - Batalla Villanueva, Ramon J. A1 - Bronstert, Axel T1 - Special issue: analysis and modelling of sediment transfer in Mediterranean river basins T2 - Journal of soils and sediments : protection, risk assessment and remediation Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-1000-7 SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 1905 EP - 1908 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Medeiros, Pedro Henrique Augusto A1 - de Araujo, Jose Carlos A1 - Mamede, George Leite A1 - Creutzfeldt, Benjamin A1 - Guentner, Andreas A1 - Bronstert, Axel T1 - Connectivity of sediment transport in a semiarid environment: a synthesis for the Upper Jaguaribe Basin, Brazil JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - Hydrosedimentological studies conducted in the semiarid Upper Jaguaribe Basin, Brazil, enabled the identification of the key processes controlling sediment connectivity at different spatial scales (10(0)-10(4) km(2)). Water and sediment fluxes were assessed from discharge, sediment concentrations and reservoir siltation measurements. Additionally, mathematical modelling (WASA-SED model) was used to quantify water and sediment transfer within the watershed. Rainfall erosivity in the study area was moderate (4600 MJ mm ha(-1) h(-1) year(-1)), whereas runoff depths (16-60 mm year(-1)), and therefore the sediment transport capacity, were low. Consequently, similar to 60 % of the eroded sediment was deposited along the landscape, regardless of the spatial scale. The existing high-density reservoir network (contributing area of 6 km(2) per reservoir) also limits sediment propagation, retaining up to 47 % of the sediment at the large basin scale. The sediment delivery ratio (SDR) decreased with the spatial scale; on average, 41 % of the eroded sediment was yielded from the hillslopes, while for the whole 24,600-km(2) basin, the SDR was reduced to 1 % downstream of a large reservoir (1940-hm(3) capacity). Hydrological behaviour in the Upper Jaguaribe Basin represents a constraint on sediment propagation; low runoff depth is the main feature breaking sediment connectivity, which limits sediment transference from the hillslopes to the drainage system. Surface reservoirs are also important barriers, but their relative importance to sediment retention increases with scale, since larger contributing areas are more suitable for the construction of dams due to higher hydrological potential. KW - Brazil KW - Connectivity KW - Sediment redistribution KW - Semiarid KW - Spatial scale Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0988-z SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 1938 EP - 1948 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - van Schaik, N. Loes M. B. A1 - Bronstert, Axel A1 - de Jong, S. M. A1 - Jetten, V. G. A1 - van Dam, J. C. A1 - Ritsema, C. J. A1 - Schnabel, Susanne T1 - Process-based modelling of a headwater catchment in a semi-arid area: the influence of macropore flow JF - Hydrological processes N2 - Subsurface stormflow is thought to occur mainly in humid environments with steep terrains. However, in semi-arid areas, preferential flow through macropores can also result in a significant contribution of subsurface stormflow to catchment runoff for varying catchment conditions. Most hydrological models neglect this important subsurface preferential flow. Here, we use the process-oriented hydrological model Hillflow-3D, which includes a macropore flow approach, to simulate rainfall-runoff in the semi-arid Parapunos catchment in Spain, where macropore flow was observed in previous research. The model was extended for this study to account for sorptivity under very dry soil conditions. The results of the model simulations with and without macropore flow are compared. Both model versions give reasonable results for average rainfall situations, although the approach with the macropore concept provides slightly better results. The model results for scenarios of extreme rainfall events (>13.3mm30min(-1)) however show large differences between the versions with and without macropores. These model results compared with measured rainfall-runoff data show that the model with the macropore concept is better. Our conclusion is that preferential flow is important in controlling surface runoff in case of specific, high intensity rainfall events. Therefore, preferential flow processes must be included in hydrological models where we know that preferential flow occurs. Hydrological process models with a less detailed process description may fit observed average events reasonably well but can result in erroneous predictions for more extreme events. Copyright (c) 2013 John Wiley & Sons, Ltd. KW - process based KW - macropore flow KW - catchment scale KW - modelling KW - semi-arid area Y1 - 2014 U6 - https://doi.org/10.1002/hyp.10086 SN - 0885-6087 SN - 1099-1085 VL - 28 IS - 24 SP - 5805 EP - 5816 PB - Wiley-Blackwell CY - Hoboken ER - TY - JOUR A1 - Bürger, Gerd A1 - Heistermann, Maik A1 - Bronstert, Axel T1 - Towards subdaily rainfall disaggregation via Clausius-Clapeyron JF - Journal of hydrometeorology N2 - Two lines of research are combined in this study: first, the development of tools for the temporal disaggregation of precipitation, and second, some newer results on the exponential scaling of heavy short-term precipitation with temperature, roughly following the Clausius-Clapeyron (CC) relation. Having no extra temperature dependence, the traditional disaggregation schemes are shown to lack the crucial CC-type temperature dependence. The authors introduce a proof-of-concept adjustment of an existing disaggregation tool, the multiplicative cascade model of Olsson, and show that, in principal, it is possible to include temperature dependence in the disaggregation step, resulting in a fairly realistic temperature dependence of the CC type. They conclude by outlining the main calibration steps necessary to develop a full-fledged CC disaggregation scheme and discuss possible applications. Y1 - 2014 U6 - https://doi.org/10.1175/JHM-D-13-0161.1 SN - 1525-755X SN - 1525-7541 VL - 15 IS - 3 SP - 1303 EP - 1311 PB - American Meteorological Soc. CY - Boston ER - TY - JOUR A1 - Müller, Eva Nora A1 - van Schaik, Loes A1 - Blume, Theresa A1 - Bronstert, Axel A1 - Carus, Jana A1 - Fleckenstein, Jan H. A1 - Fohrer, Nicola A1 - Geissler, Katja A1 - Gerke, Horst H. A1 - Gräff, Thomas A1 - Hesse, Cornelia A1 - Hildebrandt, Anke A1 - Hölker, Franz A1 - Hunke, Philip A1 - Körner, Katrin A1 - Lewandowski, Jörg A1 - Lohmann, Dirk A1 - Meinikmann, Karin A1 - Schibalski, Anett A1 - Schmalz, Britta A1 - Schröder-Esselbach, Boris A1 - Tietjen, Britta T1 - Scales, key aspects, feedbacks and challenges of ecohydrological research in Germany JF - Hydrologie und Wasserbewirtschaftung N2 - Ecohydrology analyses the interactions of biotic and abiotic aspects of our ecosystems and landscapes. It is a highly diverse discipline in terms of its thematic and methodical research foci. This article gives an overview of current German ecohydrological research approaches within plant-animal-soil-systems, meso-scale catchments and their river networks, lake systems, coastal areas and tidal rivers. It discusses their relevant spatial and temporal process scales and different types of interactions and feedback dynamics between hydrological and biotic processes and patterns. The following topics are considered key challenges: innovative analysis of the interdisciplinary scale continuum, development of dynamically coupled model systems, integrated monitoring of coupled processes at the interface and transition from basic to applied ecohydrological science to develop sustainable water and land resource management strategies under regional and global change. KW - Coastal regions KW - drylands KW - ecohydrological modelling KW - feedback KW - hyporheic zone KW - meso-scale ecosystems KW - plant-animal-soil-system KW - river networks Y1 - 2014 U6 - https://doi.org/10.5675/HyWa_2014,4_2 SN - 1439-1783 VL - 58 IS - 4 SP - 221 EP - 240 PB - Bundesanst. für Gewässerkunde CY - Koblenz ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Zimmermann, Andreas A1 - Korup, Oliver A1 - Iroume, A. A1 - Francke, Till A1 - Bronstert, Axel T1 - Seasonal logging, process response, and geomorphic work JF - Earth surface dynamics N2 - Deforestation is a prominent anthropogenic cause of erosive overland flow and slope instability, boosting rates of soil erosion and concomitant sediment flux. Conventional methods of gauging or estimating post-logging sediment flux often focus on annual timescales but overlook potentially important process response on shorter intervals immediately following timber harvest. We resolve such dynamics with non-parametric quantile regression forests (QRF) based on high-frequency (3 min) discharge measurements and sediment concentration data sampled every 30-60 min in similar-sized (similar to 0.1 km(2)) forested Chilean catchments that were logged during either the rainy or the dry season. The method of QRF builds on the random forest algorithm, and combines quantile regression with repeated random sub-sampling of both cases and predictors. The algorithm belongs to the family of decision-tree classifiers, which allow quantifying relevant predictors in high-dimensional parameter space. We find that, where no logging occurred, similar to 80% of the total sediment load was transported during extremely variable runoff events during only 5% of the monitoring period. In particular, dry-season logging dampened the relative role of these rare, extreme sediment-transport events by increasing load efficiency during more efficient moderate events. We show that QRFs outperform traditional sediment rating curves (SRCs) in terms of accurately simulating short-term dynamics of sediment flux, and conclude that QRF may reliably support forest management recommendations by providing robust simulations of post-logging response of water and sediment fluxes at high temporal resolution. Y1 - 2014 U6 - https://doi.org/10.5194/esurf-2-117-2014 SN - 2196-6311 SN - 2196-632X VL - 2 IS - 1 SP - 117 EP - 125 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Heine, Iris A1 - Francke, Till A1 - Rogass, Christian A1 - Medeiros, Pedro Henrique Augusto A1 - Bronstert, Axel A1 - Förster, Saskia T1 - Monitoring seasonal changes in the water surface areas of reservoirs using TerraSAR-X time series data in semiarid northeastern Brazil JF - IEEE journal of selected topics in applied earth observations and remote sensing N2 - The 933 km(2) Bengue catchment in northeastern Brazil is characterized by distinct rainy and dry seasons. Precipitation is stored in variously sized reservoirs, which is essential for the local population. In this study, we used TerraSAR-X SM(HH) data for an one-year monitoring of seasonal changes in the reservoir areas from July 2011 to July 2012. The monitoring was based on acquisitions in the ascending pass direction, complemented by occasional descending-pass images. To detect water surface areas, a histogram analysis followed by a global threshold classification was performed, and the results were validated using in situ GPS data. Distinguishing between small reservoirs and similar looking dark areas was difficult. Therefore, we tested several approaches for identifying misclassified areas. An analysis of the surface area dynamics of the reservoirs indicated high spatial and temporal heterogeneities and a large decrease in the total water surface area of the reservoirs in the catchment by approximately 30% within one year. KW - Image classification KW - monitoring KW - radar imaging KW - remote sensing KW - synthetic aperture radar (SAR) Y1 - 2014 U6 - https://doi.org/10.1109/JSTARS.2014.2323819 SN - 1939-1404 SN - 2151-1535 VL - 7 IS - 8 SP - 3190 EP - 3199 PB - Inst. of Electr. and Electronics Engineers CY - Piscataway ER - TY - JOUR A1 - Heistermann, Maik A1 - Francke, Till A1 - Georgi, Christof A1 - Bronstert, Axel T1 - Increasing life expectancy of water resources literature JF - Water resources research N2 - In a study from 2008, Lariviere and colleagues showed, for the field of natural sciences and engineering, that the median age of cited references is increasing over time. This result was considered counterintuitive: with the advent of electronic search engines, online journal issues and open access publications, one could have expected that cited literature is becoming younger. That study has motivated us to take a closer look at the changes in the age distribution of references that have been cited in water resources journals since 1965. Not only could we confirm the findings of Lariviere and colleagues. We were also able to show that the aging is mainly happening in the oldest 10-25% of an average reference list. This is consistent with our analysis of top-cited papers in the field of water resources. Rankings based on total citations since 1965 consistently show the dominance of old literature, including text books and research papers in equal shares. For most top-cited old-timers, citations are still growing exponentially. There is strong evidence that most citations are attracted by publications that introduced methods which meanwhile belong to the standard toolset of researchers and practitioners in the field of water resources. Although we think that this trend should not be overinterpreted as a sign of stagnancy, there might be cause for concern regarding how authors select their references. We question the increasing citation of textbook knowledge as it holds the risk that reference lists become overcrowded, and that the readability of papers deteriorates. Y1 - 2014 U6 - https://doi.org/10.1002/2014WR015674 SN - 0043-1397 SN - 1944-7973 VL - 50 IS - 6 SP - 5019 EP - 5028 PB - American Geophysical Union CY - Washington ER - TY - JOUR A1 - Bronstert, Axel A1 - de Araujo, Jose-Carlos A1 - Batalla Villanueva, Ramon J. A1 - Costa, Alexandre Cunha A1 - Delgado, José Miguel Martins A1 - Francke, Till A1 - Förster, Saskia A1 - Guentner, Andreas A1 - Lopez-Tarazon, José Andrés A1 - Mamede, George Leite A1 - Medeiros, Pedro Henrique Augusto A1 - Mueller, Eva A1 - Vericat, Damia T1 - Process-based modelling of erosion, sediment transport and reservoir siltation in mesoscale semi-arid catchments JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - To support scientifically sound water management in dryland environments a modelling system has been developed for the quantitative assessment of water and sediment fluxes in catchments, transport in the river system, and retention in reservoirs. The spatial scale of interest is the mesoscale because this is the scale most relevant for management of water and land resources. This modelling system comprises process-oriented hydrological components tailored for dryland characteristics coupled with components comprising hillslope erosion, sediment transport and reservoir deposition processes. The spatial discretization is hierarchically designed according to a multi-scale concept to account for particular relevant process scales. The non-linear and partly intermittent run-off generation and sediment dynamics are dealt with by accounting for connectivity phenomena at the intersections of landscape compartments. The modelling system has been developed by means of data from nested research catchments in NE-Spain and in NE-Brazil. In the semi-arid NE of Brazil sediment retention along the topography is the main process for sediment retention at all scales, i.e. the sediment delivery is transport limited. This kind of deposition retains roughly 50 to 60 % of eroded sediment, maintaining a similar deposition proportion in all spatial scales investigated. On the other hand, the sediment retained in reservoirs is clearly related to the scale, increasing with catchment area. With increasing area, there are more reservoirs, increasing the possibility of deposition. Furthermore, the area increase also promotes an increase in flow volume, favouring the construction of larger reservoirs, which generally overflow less frequently and retain higher sediment fractions. The second example comprises a highly dynamic Mediterranean catchment in NE-Spain with nested sub-catchments and reveals the full dynamics of hydrological, erosion and deposition features. The run-off modelling performed well with only some overestimation during low-flow periods due to the neglect of water losses along the river. The simulated peaks in sediment flux are reproduced well, while low-flow sediment transport is less well captured, due to the disregard of sediment remobilization in the riverbed during low flow. This combined observation and modelling study deepened the understanding of hydro-sedimentological systems characterized by flashy run-off generation and by erosion and sediment transport pulses through the different landscape compartments. The connectivity between the different landscape compartments plays a very relevant role, regarding both the total mass of water and sediment transport and the transport time through the catchment. KW - Connectivity KW - Deposition KW - Erosion KW - Modelling KW - Sediment transfer KW - Semi-arid Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0994-1 SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 2001 EP - 2018 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Brosinsky, Arlena A1 - Förster, Saskia A1 - Segl, Karl A1 - Lopez-Tarazon, José Andrés A1 - Pique, Gemma A1 - Bronstert, Axel T1 - Spectral fingerprinting: characterizing suspended sediment sources by the use of VNIR-SWIR spectral information JF - Journal of soils and sediments : protection, risk assessment and remediation N2 - Knowledge of sediment sources is a prerequisite for sustainable management practices and may furthermore improve our understanding of water and sediment fluxes. Investigations have shown that a number of characteristic soil properties can be used as "fingerprints" to trace back the sources of river sediments. Spectral properties have recently been successfully used as such characteristics in fingerprinting studies. Despite being less labour-intensive than geochemical analyses, for example, spectroscopy allows measurements of small amounts of sediment material (> 60 mg), thus enabling inexpensive analyses even of intra-event variability. The focus of this study is on the examination of spectral properties of fluvial sediment samples to detect changes in source contributions, both between and within individual flood events. Sediment samples from the following three different origins were collected in the Isabena catchment (445 km(2)) in the central Spanish Pyrenees: (1) soil samples from the main potential source areas, (2) stored fine sediment from the channel bed once each season in 2011 and (3) suspended sediment samples during four flood events in autumn 2011 and spring 2012 at the catchment outlet as well as at several subcatchment outlets. All samples were dried and measured for spectral properties in the laboratory using an ASD spectroradiometer. Colour parameters and physically based features (e.g. organic carbon, iron oxide and clay content) were calculated from the spectra. Principal component analyses (PCA) were applied to all three types of samples to determine natural clustering of samples, and a mixing model was applied to determine source contributions. We found that fine sediment stored in the river bed seems to be mainly influenced by grain size and seasonal variability, while sampling location-and thus the effect of individual tributaries or subcatchments-seem to be of minor importance. Suspended sediment sources were found to vary between, as well as within, flood events; although badlands were always the major source. Forests and grasslands contributed little (< 10 %), and other sources (not further determinable) contributed up to 40 %. The analyses further suggested that sediment sources differ among the subcatchments and that subcatchments comprising relatively large proportions of badlands contributed most to the four flood events analyzed. Spectral fingerprints provide a rapid and cost-efficient alternative to conventional fingerprint properties. However, a combination of spectral and conventional fingerprint properties could potentially permit discrimination of a larger number of source types. KW - Isabena river KW - Mixing models KW - Northeast Spain KW - Sediment fingerprinting KW - Spectroscopy KW - Suspended sediment Y1 - 2014 U6 - https://doi.org/10.1007/s11368-014-0927-z SN - 1439-0108 SN - 1614-7480 VL - 14 IS - 12 SP - 1965 EP - 1981 PB - Springer CY - Heidelberg ER - TY - JOUR A1 - Mohr, Christian Heinrich A1 - Manga, Michael A1 - Wang, Chi-yuen A1 - Kirchner, James W. A1 - Bronstert, Axel T1 - Shaking water out of soil JF - Geology N2 - Moderate to large earthquakes can increase the amount of water flowing in streams. Previous interpretations and models assume that the extra water originates in the saturated zone. Here we show that earthquakes may also release water from the unsaturated zone when the seismic energy is sufficient to overcome the threshold of soil water retention. Soil water may then be released into aquifers, increasing streamflow. After the M8.8 Maule, Chile, earthquake, the discharge in some headwater catchments of the Chilean coastal range increased, and the amount of extra water in the discharge was similar to the total amount of water available for release from the unsaturated zone. Assuming rapid recharge of this water to the water table, a groundwater flow model that accounts for evapotranspiration and water released from soils can reproduce the increase in discharge as well as the enhanced diurnal discharge variations observed after the earthquake. Thus the unsaturated zone may play a previously unappreciated, and potentially significant, role in shallow hydrological responses to earthquakes. Y1 - 2015 U6 - https://doi.org/10.1130/G36261.1 SN - 0091-7613 SN - 1943-2682 VL - 43 IS - 3 SP - 207 EP - 210 PB - American Institute of Physics CY - Boulder ER - TY - JOUR A1 - Vormoor, Klaus Josef A1 - Lawrence, D. A1 - Heistermann, Maik A1 - Bronstert, Axel T1 - Climate change impacts on the seasonality and generation processes of floods BT - projections and uncertainties for catchments with mixed snowmelt/rainfall regimes JF - Hydrology and earth system sciences : HESS N2 - Climate change is likely to impact the seasonality and generation processes of floods in the Nordic countries, which has direct implications for flood risk assessment, design flood estimation, and hydropower production management. Using a multi-model/multi-parameter approach to simulate daily discharge for a reference (1961–1990) and a future (2071–2099) period, we analysed the projected changes in flood seasonality and generation processes in six catchments with mixed snowmelt/rainfall regimes under the current climate in Norway. The multi-model/multi-parameter ensemble consists of (i) eight combinations of global and regional climate models, (ii) two methods for adjusting the climate model output to the catchment scale, and (iii) one conceptual hydrological model with 25 calibrated parameter sets. Results indicate that autumn/winter events become more frequent in all catchments considered, which leads to an intensification of the current autumn/winter flood regime for the coastal catchments, a reduction of the dominance of spring/summer flood regimes in a high-mountain catchment, and a possible systematic shift in the current flood regimes from spring/summer to autumn/winter in the two catchments located in northern and south-eastern Norway. The changes in flood regimes result from increasing event magnitudes or frequencies, or a combination of both during autumn and winter. Changes towards more dominant autumn/winter events correspond to an increasing relevance of rainfall as a flood generating process (FGP) which is most pronounced in those catchments with the largest shifts in flood seasonality. Here, rainfall replaces snowmelt as the dominant FGP primarily due to increasing temperature.We further analysed the ensemble components in contributing to overall uncertainty in the projected changes and found that the climate projections and the methods for downscaling or bias correction tend to be the largest contributors. The relative role of hydrological parameter uncertainty, however, is highest for those catchments showing the largest changes in flood seasonality, which confirms the lack of robustness in hydrological model parameterization for simulations under transient hydrometeorological conditions. Y1 - 2015 U6 - https://doi.org/10.5194/hess-19-913-2015 SN - 1027-5606 SN - 1607-7938 VL - 19 IS - 2 SP - 913 EP - 931 PB - Copernicus Publications CY - Göttingen ER -