TY - CHAP A1 - Grünewald, Uwe A1 - Schümberg, Sabine T1 - Das Oderhochwasser 1997 ; Ursachen, Verlauf, Schlussfolgerungen und historischer Vergleich KW - Hochwasser Y1 - 2000 SN - 3-9803607-8-4 PB - Selbstverlag des Institutes für Geographie der Pädagogischen Hochschule Erfurt ER - TY - GEN A1 - Grünewald, Uwe A1 - Kaltofen, Michael A1 - Schümberg, Sabine T1 - Ursachen, Verlauf und Folgen des Sommerhochwassers 1997 an der Oder sowie Aussagen zu bestehenden Risikopotentialen T2 - Forum der Forschung KW - Hochwasser Y1 - 1998 SN - 0947-6989 IS - 7 SP - 104 EP - 108 ER - TY - BOOK A1 - Grünewald, Uwe A1 - Chmielewski, Robert A1 - Kaltofen, Michael A1 - Rolland, Wolfgang A1 - Schümberg, Sabine A1 - Ahlheim, Michael A1 - Sauer, Thoma A1 - Wagner, Ralf A1 - Schluchter, Wolfgang T1 - Ursachen, Verlauf und Folgen des Sommer-Hochwassers 1997 an der Oder sowie Aussagen zu bestehenden Risikopotentialen : eine interdisziplinäre Studie KW - Hochwasser Y1 - 1998 SN - 3-933181-03-8 N1 - Langfassung PB - IDNDR CY - Bonn ER - TY - BOOK A1 - Grünewald, Uwe A1 - Chmielewski, Robert A1 - Kaltofen, Michael A1 - Rolland, Wolfgang A1 - Schümberg, Sabine T1 - Ursachen, Verlauf und Folgen des Sommer-Hochwassers 1997 an der Oder sowie Aussagen zu bestehenden Risikopotentialen : eine interdisziplinäre Studie KW - Hochwasser Y1 - 1998 SN - 3-933181-06-2 N1 - Kurzfassung PB - IDNDR CY - Bonn ER - TY - BOOK A1 - Grünewald, Uwe A1 - Chmielewski, Robert A1 - Kaltofen, Michael A1 - Rolland, Wolfgang A1 - Schümberg, Sabine T1 - The Causes, Progression and Consequences of the River Oder Floods in Summer 1997 Including Remarks on the Existence of Risk Potential. An Interdisciplinary Study ; Abridged Version. N2 - German IDNDR-Series 10e KW - flood Y1 - 1998 SN - 3-933181-06-2 PB - Bonn : German IDNDR Committee for Natural Disaster Reduction ER - TY - BOOK A1 - Grünewald, Uwe A1 - Schümberg, Sabine A1 - Petrow, Theresia A1 - Thieken, Annegret A1 - Dombrowsky, Wolf R. T1 - Hochwasservorsorge in Deutschland : Lernen aus der Katastrophe 2002 im Elbegebiet Y1 - 2003 SN - 3-933181-32-1 N1 - Kurzfassung der Studie PB - DKKV CY - Bonn ER - TY - BOOK A1 - Grünewald, Uwe A1 - Schümberg, Sabine T1 - Flood Risk Reduction in Germany - Lessons Learned from the 2002 Disaster in the Elbe Region : Summary of the Study N2 - DKKV Publication ; 29e, ISBN 3-933181-34-8 Y1 - 2004 UR - http://www.dkkv.org/upload/hochwasservorsorge_kurzfassung_engl.pdf PB - Bonn : Deutsches Komitee für Katastrophenvorsorge e.V. ER - TY - JOUR A1 - Bartl, Steffen A1 - Grünewald, Uwe A1 - Schümberg, Sabine T1 - Zur Rekonstruktion langjähriger Wasserstands- und Durchflusszeitreihen am Elbepegel Dresden Y1 - 2008 ER - TY - CHAP A1 - Pohle, Ina A1 - Gädeke, Anne A1 - Koch, Hagen A1 - Schümberg, Sabine A1 - Hinz, Christoph ED - Schütze, Niels ED - Müller, Uwe ED - Schwarze, Robert ED - Wöhling, Thomas ED - Grundmann, Jens T1 - Kann Wasserressourcenbewirtschaftung die Unsicherheiten projizierter Klimafolgen auf den Abfluss vermindern? - Ein Vergleich in zwei hydrologisch ähnlichen Einzugsgebieten mit unterschiedlichem Ausmaß des Bewirtschaftungseinflusses T2 - M³ - Messen, Modellieren, Managen in Hydrologie und Wasserressourcenbewirtschaftung. Beiträge zum Tag der Hydrologie am 22./23. März 2018 an der Technischen Universität Dresden N2 - Studien zum Einfluss des zukünftigen Klimawandels auf das Abflussgeschehen fokussieren oft auf die Fortpflanzung von Unsicherheiten in Modellkaskaden, berücksichtigen meist jedoch die Wasserressourcenbewirtschaftung nur ungenügend. Wir untersuchten den Einfluss der Wasserressourcenbewirtschaftung auf die Abflussvariabilität und die Fortpflanzung von Unsicherheiten von Klimaprojektionen auf Abflusssimulationen in den Einzugsgebieten von Spree (bis Pegel Große Tränke: 6200 km²) und Schwarzer Elster (5700 km²). Die Einzugsgebiete ähneln sich hinsichtlich Klima, Topographie, Boden und Landnutzung, jedoch ist das Spreeeinzugsgebiet stärker durch den Braunkohletagebau und die damit verbundenen Bewirtschaftung geprägt und durch einen höheren Speicherausbaugrad gekennzeichnet. Um zwischen Bewirtschaftungseinflüssen und meteorologischen Einflüssen zu separieren, wurden für den Zeitraum 1961-2005 beobachtete Abflüsse mit durch das Modell SWIM rekonstruierten natürlichen (d.h. ohne Bewirtschaftungseinfluss) Abflüssen der Vergangenheit verglichen. Mögliche Einflüsse des Klimawandels wurden für den Zeitraum 2018-2052 auf Grundlage von 3 Szenarien des statistischen Regionalmodells STAR (je 100 Realisierungen) mit SWIM (natürliche Abflüsse) und dem Langfristbewirtschaftungsmodell WBalMo (bewirtschaftete Abflüsse) modelliert. Die Analyse erfolgte mit Fokus auf Saisonalität, Oszillation, Verteilung und räumliche Variabilität der Abflüsse. Der Vergleich zwischen beobachteten und natürlichen Abflüssen der vergangenen Jahrzehnte zeigt, dass die zwischenjährliche Abflussvariabilität im Spreeeinzugsgebiet stärker durch Grubenwassereinleitungen als durch natürliche hydrologische Prozesse bestimmt wurde. Zusätzlich führt der höhere Speicherausbaugrad dazu, dass die kurzzeitliche und saisonale Variabilität im Spreeeinzugsgebiet geringer als im Einzugsgebiet der Schwarzen Elster ist. Simulationen mit Klimaszenarien, welche steigende Jahresmitteltemperaturen und einen Rückgang der Niederschlagsjahressummen enthalten, führen zu deutlichen Abflussrückgängen. Die Unterschiede der natürlichen Abflüsse beider Einzugsgebiete sind gering, die Unsicherheiten der Klimaprojektionen werden durch die hydrologische Modellierung verstärkt. Die natürlichen und bewirtschafteten Abflüsse der Schwarzen Elster unter Klimawandel unterscheiden sich kaum. Im Spreeeinzugsgebiet zeigt sich eine deutliche Verringerung der Variabilität und Unsicherheiten unter Klimawandel von den natürlichen zu den bewirtschafteten Abflüssen. Die Analysen zeigen, dass effektive Wasserressourcenbewirtschaftung die Abflussvariabilität verringern kann und damit auch dazu beitragen kann, die sich aus Klimawandelprojektionen ergebenden Unsicherheiten zu vermindern. Einzugsgebiete mit einem hohen Ausbaugrad weisen weniger Vulnerabilität bezüglich klimatischer Änderungen auf. Dies unterstreicht die Bedeutung von Wasserresourcenbewirt-schaftungfür die Anpassung an den Klimawandel. Y1 - 2018 UR - https://tu-dresden.de/bu/umwelt/hydro/ihm/hydrologie/ressourcen/dateien/tdh2018/TdH_2018_Abstractband.pdf SP - S. 30 PB - Technische Universität CY - Dresden ER - TY - CHAP A1 - Pohle, Ina A1 - Gädeke, Anne A1 - Koch, Hagen A1 - Schümberg, Sabine A1 - Hinz, Christoph T1 - Can water resources management alleviate the uncertainty of projected climate change impacts on river discharge? - A comparative study in two hydrologically similar catchments with different level of management T2 - International Soil and Water Assessment Tool Conference. SWAT 2017, June 28 – 30, Warsaw, Poland, Book of Abstracts N2 - Climate change impact studies are associated with error propagation and amplification of uncertainties through model chains from global climate models down to impact (e.g. hydrological) models. The effect of water management, which reduces discharge variability, is often not considered in climate change impact studies. Here, we investigated how water resources management influences discharge variability and uncertainty propagation of climate change scenarios by combining the analyses of observed flow records and model-based climate change impact simulations. Two neighbouring catchments, the Schwarze Elster River (Germany) and the Spree River (Germany and Czech Republic) which are similar in climate, topography and land use, but different in terms of water resources management were chosen as study area. The intense water resources management in the Spree River catchment includes a high reservoir capacity, water use in terms of mining discharges and water withdrawals by power plants as well as water transfers. The analysis of historical flow records focusses on variability indices (Parde index, Richards-Baker-Flashiness Index, Interquartile Ratio and Baseflow Index). The climate change impact simulations were carried out using a model cascade of (i) the statistical regional model STAR (100 stochastically generated realizations each for 3 scenarios with different prescribed temperature trend), (ii) the hydrological models SWIM and EGMO, and (iii) the water resources management model WBalMo. The analysis of the observed discharges reveals that the annual discharge variability in the Spree catchment is dominated by mining activities rather than natural rainfall-runoff processes. Due to the high reservoir capacity in the Spree catchment its discharge is characterised by less seasonality and short-term variability compared to the Schwarze Elster. Simulations with climate change scenarios assuming increasing temperature and decreasing precipitation result in pronounced reductions of discharge in both catchments. The differences in potential natural discharges between the Schwarze Elster and the Spree catchments as projected by the hydrological models SWIM and EGMO are marginal. The uncertainties related to the climate projection are propagated through the hydrological models. In the Schwarze Elster catchment, the managed discharges simulated by WBalMo are comparable to the potential natural discharges. In the Spree River however, the short-term variability is moderated by water resources management and managed discharge under climate change is less affected by amplification of uncertainties through model chains. The results of the study, which combines the analyses of observed flow records and model-based climate change impact simulations, imply that generally, effective water resources management reducing discharge variability hence also reduces uncertainty related to climate change impacts on river discharge. Catchments with a high storage ratio are thus less vulnerable to changing climate conditions. This underlines the role of water resources management in coping with climate change impacts. Yet, due to decreasing reservoir volumes in drought periods, reservoir management alone cannot compensate strong changes in climate conditions over long time periods. KW - SWIM KW - climate change KW - uncertainty KW - water resources management KW - model comparison Y1 - 2017 UR - http://swat.tamu.edu/media/115571/book-of-abstracts-2017-06-25.pdf SP - 10 EP - 11 ER - TY - CHAP A1 - Pohle, Ina A1 - Niebisch, Michael A1 - Zha, Tingting A1 - Schümberg, Sabine A1 - Müller, Hannes A1 - Maurer, Thomas A1 - Hinz, Christoph T1 - A stochastical event-based continuous time step rainfall generator based on Poisson rectangular pulse and microcanonical random cascade models T2 - European Geosciences Union General Assembly 2017 Vienna, Austria, 23–28 April 2017 N2 - Rainfall variability within a storm is of major importance for fast hydrological processes, e.g. surface runoff, erosion and solute dissipation from surface soils. To investigate and simulate the impacts of within-storm variabilities on these processes, long time series of rainfall with high resolution are required. Yet, observed precipitation records of hourly or higher resolution are in most cases available only for a small number of stations and only for a few years. To obtain long time series of alternating rainfall events and interstorm periods while conserving the statistics of observed rainfall events, the Poisson model can be used. Multiplicative microcanonical random cascades have been widely applied to disaggregate rainfall time series from coarse to fine temporal resolution. We present a new coupling approach of the Poisson rectangular pulse model and the multiplicative microcanonical random cascade model that preserves the characteristics of rainfall events as well as inter-storm periods. In the first step, a Poisson rectangular pulse model is applied to generate discrete rainfall events (duration and mean intensity) and inter-storm periods (duration). The rainfall events are subsequently disaggregated to high-resolution time series (user-specified, e.g. 10 min resolution) by a multiplicative microcanonical random cascade model. One of the challenges of coupling these models is to parameterize the cascade model for the event durations generated by the Poisson model. In fact, the cascade model is best suited to downscale rainfall data with constant time step such as daily precipitation data. Without starting from a fixed time step duration (e.g. daily), the disaggregation of events requires some modifications of the multiplicative microcanonical random cascade model proposed by Olsson (1998): Firstly, the parameterization of the cascade model for events of different durations requires continuous functions for the probabilities of the multiplicative weights, which we implemented through sigmoid functions. Secondly, the branching of the first and last box is constrained to preserve the rainfall event durations generated by the Poisson rectangular pulse model. The event-based continuous time step rainfall generator has been developed and tested using 10 min and hourly rainfall data of four stations in North-Eastern Germany. The model performs well in comparison to observed rainfall in terms of event durations and mean event intensities as well as wet spell and dry spell durations. It is currently being tested using data from other stations across Germany and in different climate zones. Furthermore, the rainfall event generator is being applied in modelling approaches aimed at understanding the impact of rainfall variability on hydrological processes. Y1 - 2017 UR - http://meetingorganizer.copernicus.org/EGU2017/EGU2017-9648.pdf N1 - EGU2017-9648 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - BOOK A1 - Ebner von Eschenbach, Anna-Dorothea A1 - Helms, Martin A1 - Kleinhans, Alexander A1 - Laaha, Gregor A1 - Schümberg, Sabine A1 - Walther, Jörg A1 - Willems, Winfried A1 - Wittenberg, Hartmut T1 - Statistische Analyse von Niedrigwasserkenngrößen N2 - Niedrigwasser ist ein integraler Bestandteil des Abflussregimes, der einen zeitlich und regional begrenzten Zustand in einem oberirdischen Gewässer beschreibt, bei dem der Wasserstand oder der Abfluss einen bestimmten Schwellenwert erreicht oder unterschreitet. Die Kenntnis der Niedrigwasserverhältnisse in einem Gewässer hat damit große Bedeutung für seine zielgerichtete wasserwirtschaftliche Nutzung und ökologische Bewertung. Niedrigwasser ist in erster Linie bedingt durch Niederschlagsmangel, kann sich jedoch auch durch den Rückhalt des Niederschlags in der Schneedecke, in Gletschern oder im gefrorenen Untergrund ergeben. Zudem kann es anthropogen durch diverse Bewirtschaftungsmaßnahmen im Gewässer oder dessen Einzugsgebiet verstärkt oder abgeschwächt werden. In diesem Merkblatt werden zunächst die wichtigsten Kenngrößen für das Niedrigwasser definiert: Niedrigwasserabfluss bzw. -wasserstand, Unterschreitungsdauer, Abflussdefizit sowie aus der Dauerlinie abgeleitete Quantile. Für die Ermittlung der Unterschreitungsdauer und des Abflussdefizits sind Schwellenwerte erforderlich. Sie sollten in Abhängigkeit von der Zielstellung der Untersuchung festgelegt werden. Es werden sowohl die natürlichen und anthropogenen Einflussgrößen auf das Niedrigwasser diskutiert, als auch die genannten Kenngrößen und deren Ableitung aus der Ganglinie vorgestellt. Darauf aufbauend entwickeln sich inhaltlich die Kernthemen des Merkblatts: (1) Wahrscheinlichkeitsanalyse von Niedrigwasserabflüssen und (2) Wahrscheinlichkeitsanalyse von Unterschreitungsdauern und Abflussdefiziten. Mit Hilfe eines Verfahrensablaufs und anhand von Beispielen wird dem Leser schrittweise das methodische Vorgehen vermittelt – von der Festlegung der Kenngröße bis hin zur Ermittlung ihrer Quantile und deren Konfidenzgrenzen. Beide Verfahren setzen Stationarität der zugrundeliegenden Serien voraus, sodass im dritten Kernthema des Merkblatts (instationäre Wahrscheinlichkeitsanalyse) diskutiert wird, welche Möglichkeiten bestehen, um mit signifikanten Instationaritäten im Rahmen der Wahrscheinlichkeitsanalyse umzugehen. Y1 - 2022 SN - 978-3-96862-221-7 SN - 978-3-96862-222-4 PB - DWA, Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V. CY - Hennef ET - Juli 2022 ER - TY - GEN A1 - Ebner von Eschenbach, Anna A1 - Helms, Martin A1 - Kleinhans, Alexander A1 - Laaha, Gregor A1 - Schümberg, Sabine A1 - Walther, Jörg A1 - Willems, Winfried T1 - DWA-AG HW-3.1: „Niedrigwasser“ – unser Weg zum neuen Merkblatt DWA-M 541 „Statistische Analyse von Niedrigwasserkenngrößen“ T1 - DWA working group HW-3.1: ‘Low-water flow’ – our journey to developing the new advisory leaflet DWA-M 541 ‘Statistical Analysis of Low-Water Flow Parameters’ T2 - KW Korrespondenz Wasserwirtschaft N2 - Nach mehrjähriger Arbeit der DWA-Arbeitsgruppe HW-3.1 „Niedrigwasser“ hat die DWA im Oktober 2020 den Gelbdruck für das Merkblatt DWA-M 541 „Statistische Analyse von Niedrigwasserkenngrößen“ veröffentlicht. Mehr als 100 Anmerkungen gingen zum Gelbdruck ein, die die Arbeitsgruppe akribisch geprüft hat. Der Weißdruck des Merkblattes steht nun kurz bevor. Der Beitrag stellt die inhaltlichen Kernpunkte des Merkblattes vor, schildert die Entstehung des Merkblattes und bietet einen Ausblick auf die kommenden Aufgaben der Arbeitsgruppe. N2 - The DWA published a preliminary version of advisory leaflet DWA-M 541 ‘Statistical Analysis of Low-Water Flow Parameters’ in October 2020 after several years of work by the DWA working group HW 3.1 ‘Low-Water Flow’. More than 100 comments were incorporated into the draft, which was reviewed meticulously by the working group. A final version of the advisory leaflet is now imminent. This article looks at the substantive core elements of the advisory leaflet, describes the process of its creation and provides a look ahead to the work group’s forthcoming tasks. KW - Niedrigwasser KW - Statistische Analyse KW - DWA-M 541 KW - low-water flow KW - statistical analysis Y1 - 2021 SN - 1865-9926 VL - 14 IS - 10 SP - 625 EP - 630 ER - TY - CHAP A1 - Zaplata, Markus Klemens A1 - Veste, Maik A1 - Pohle, Ina A1 - Schümberg, Sabine A1 - Abreu Schonert, Iballa A1 - Hinz, Christoph T1 - Experimental investigation of the early interaction between cyanobacterial soil crusts and vascular plants T2 - European Geosciences Union, General Assembly 2016, Vienna, Austria N2 - While there are hints that biological soil crusts (BSCs) can constitute physical barriers for the emergence of vascular plants, a conceptual approach for the quantitative evaluation of these effects is still missing. Here we present an experimental design to test the emergence of seedlings in situ with (i) capping natural intact, (ii) destroyed and (iii) removed BSC. The selected field site is directly adjacent to the constructed Hühnerwasser catchment (Lusatia, Germany). This site exists since the end of 2008 and consists of loamy sand. Serving as proxy for seedling thrust, we inserted pre-germinated seeds of three confamiliar plant species with different seed masses (members of the Fabaceae family: Lotus corniculatus L., Ornithopus sativus Brot., and Glycine max (L.) Merr.). In each treatment as well as in the control group planting depths were 10 mm. We took care that experimental plots had identical crust thickness, slightly less than 4 mm, serving as proxy for mechanical resistance. A plot became established as follows: Firstly, the pristine crusted surface was vertically cut. To the windward side the BSC remained intact (i: “with BSC” stripe). To the downwind side soil material was temporarily excavated for laterally inserting the seeds beneath the surface of the first stripe. Then at the thereby disturbed second stripe pulverised BSC material became filled as a top layer (ii: “BSC mix” stripe). From the next stripe the BSC was removed (iii : “no BSC” stripe). Thus each plot had each experimental group in spatial contiguity (within 50 cm * 50 cm). The overall 50 plots were distributed across an area of 40 m * 12 m. When individuals of a species either emerged at all stripes, “XXX”, or at no stripe of a plot, “– – –“, there was no reason to suppose any effect of a crust. The “–XX” emergence pattern (depicting the appearance of seedlings in both stripes possessing manipulated surfaces) points towards hindrance more clearly than “–X–” or “– - X”. Altogether eight possible combinations exist. Combinatorial analysis turned out that seedling emergence had been notably impeded for light-weighted seeds but little for heavy seeds. Repeated recordings enable to account for adaptable emergence of seedlings according to varying crust conditions – in spatial as well as temporal terms. The proposed experimental procedure hence is highly recommended as a viable instrument to further investigate filter and facilitation processes between BSCs and vascular plants. Y1 - 2016 UR - http://meetingorganizer.copernicus.org/EGU2016/EGU2016-8595.pdf N1 - EGU2016-8595 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - GEN A1 - Pohle, Ina A1 - Niebisch, Michael A1 - Müller, Hannes A1 - Schümberg, Sabine A1 - Zha, Tingting A1 - Maurer, Thomas A1 - Hinz, Christoph T1 - Coupling Poisson rectangular pulse and multiplicative microcanonical random cascade models to generate subdaily precipitation time series T2 - Journal of Hydrology N2 - To simulate the impacts of within-storm rainfall variabilities on fast hydrological processes, long precipi-tation time series with high temporal resolution are required. Due to limited availability of observed data such time series are typically obtained from stochastic models. However, most existing rainfall models are limited in their ability to conserve rainfall event statistics which are relevant for hydrological pro-cesses. Poisson rectangular pulse models are widely applied to generate long time series of alternating precipitation events durations and mean intensities as well as interstorm period durations. Multiplicative microcanonical random cascade (MRC) models are used to disaggregate precipitation time series from coarse to fine temporal resolution. To overcome the inconsistencies between the temporal structure of the Poisson rectangular pulse model and the MRC model, we developed a new coupling approach by introducing two modifications to the MRC model. These modifications comprise (a) a modified cascade model (“constrained cascade”) which preserves the event durations generated by the Poisson rectangular model by constraining the first and last interval of a precipitation event to contain precipitation and (b) continuous sigmoid func-tions of the multiplicative weights to consider the scale-dependency in the disaggregation of precipita-tion events of different durations. The constrained cascade model was evaluated in its ability to dis-aggregate observed precipitation events in comparison to existing MRC models. For that, we used a 20-year record of hourly precipitation at six stations across Germany. The constrained cascade model showed a pronounced better agreement with the observed data in terms of both the temporal pattern of the precipitation time series (e.g. the dry and wet spell durations and autocorrelations) and event char-acteristics (e.g. intra-event intermittency and intensity fluctuation within events). The constrained cas-cade model also slightly outperformed the other MRC models with respect to the intensity-frequency relationship. To assess the performance of the coupled Poisson rectangular pulse and constrained cascade model, precipitation events were stochastically generated by the Poisson rectangular pulse model and then disaggregated by the constrained cascade model. We found that the coupled model performs satisfac-torily in terms of the temporal pattern of the precipitation time series, event characteristics and the in-tensity-frequency relationship. KW - Rainfall generator KW - Disaggregation KW - Precipitation event KW - Autocorrelation KW - Within-event variability KW - Intra-event intermittency Y1 - 2018 U6 - https://doi.org/10.1016/j.jhydrol.2018.04.063 SN - 0022-1694 VL - 562 SP - 50 EP - 70 ER - TY - BOOK A1 - Schümberg, Sabine A1 - Bartl, Steffen A1 - Grünewald, Uwe T1 - Erschließung und Einbeziehung historischer Informationen für die Ermittlung extremer Hochwasserabflüsse - Fallbeispiele und Empfehlungen - DWA-Themen Y1 - 2008 SN - 978-3-940173-75-1 PB - Hennef : Deutsche Vereinigung für Wasserwirtschaft, Abwasser und Abfall e.V. ER - TY - GEN A1 - Bartl, Steffen A1 - Schümberg, Sabine A1 - Deutsch, Mathias T1 - Revising time series of the Elbe river discharge for flood frequency determination at gauge Dresden Y1 - 2009 ER - TY - CHAP A1 - Grünewald, Uwe A1 - Schümberg, Sabine A1 - Merz, Bruno A1 - Thieken, Annegret A1 - Petrow, Theresia A1 - Kreibich, Heidi A1 - Streitz, Willi A1 - Kaltofen, Michael T1 - Flood risk reduction in Germany after the Elbe 2002 flood : aspects of hazard mapping and early warning systems Y1 - 2005 ER - TY - CHAP A1 - Hinz, Christoph A1 - Schümberg, Sabine A1 - Kubitz, Anita A1 - Frank, Franzi A1 - Cheng, Zhang A1 - Frechen, Tobias Nanu A1 - Pohle, Ina T1 - Dynamic effects of wet-dry cycles and crust formation on the saturated hydraulic conductivity of surface soils in the constructed Hühnerwasser (“Chicken Creek”) catchment T2 - European Geosciences Union, General Assembly 2016, Vienna, Austria N2 - Highly disturbed soils and substrates used in land rehabilitation undergo rapid changes after the first wetting events which in turn can lead to ecosystem degradation. Such changes were detected during the early development of the constructed Hühnerwasser (“Chicken Creek”) catchment in Lusatia, Germany. Surface substrates consisting of quaternary sandy sediments formed surface seals during the first rainfall events leading to reduced infiltration and substantially increased surface runoff. Subsequently biological soil crusts formed and stabilised the surface. The aim of this study is to investigate the factors that cause the hydraulic conductivity to decrease using undisturbed and disturbed soil samples. Based on the hypothesis that physical and biological crusts lower the hydraulic conductivity, the first set of experiments with undisturbed soil cores from the Hühnerwasser catchment were carried out to measure the saturated hydraulic conductivity using the constant head method. Measurements were done with intact cores and repeated after the surface crust was removed. As the quaternary glacial sediments tend to display hard setting behaviour, we further hypothesised that the mobilisation of fine particles within the cores lead to pore clogging and that wet-dry cycles will therefore decrease hydraulic conductivity. A second set of experiments using the same methodology consisted of five repeated measurements of hydraulic conductivity after each drying cycle. These measurements were done with undisturbed core samples as well as repacked cores in order to assess how dry packing affects the dynamics of the hydraulic conductivity somewhat similar to the situation during the first wetting after completion of the catchment construction. For all experiments, the temporal evolution of hydraulic conductivity was measured and the turbidity of the effluent was recorded. The results clearly demonstrated that the substrate is highly unstable. The first set of experiments showed that the removal of the crust lead generally to a decrease in hydraulic conductivity. The process of crust removal represented a severe disturbance of the surface soil which to our understanding causes particle mobilisation and subsequent pore clogging. The first hypothesis could neither be rejected nor accepted. The second set of experiments showed that the hydraulic conductivity significantly dropped in particular after the first drying event. This was observed for both undisturbed and repacked samples. The following drying cycles further decreased the hydraulic conductivity in the repacked samples. The decrease in hydraulic conductivity was positively correlated to turbidity values in the effluent of the samples, indicating particle mobilisation in all samples. The results imply that hydraulic properties in such substrates undergo rapid changes that depend on the temporal dynamics of atmospheric drivers, precipitation and evaporative demand, controlling the degree of wetness and the rate and degree of drying during the very early stage after placement. Associated with the dynamics of the atmospheric drivers are the biological changes due to the formation of biological soil crusts and the establishment of vegetation, both of them contributing to the stabilisation of hydraulic properties. Y1 - 2016 UR - http://meetingorganizer.copernicus.org/EGU2016/EGU2016-15908-1.pdf N1 - EGU2016-15908-1 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - RPRT A1 - Grünewald, Uwe A1 - Schoenheinz, Dagmar A1 - Ender, Remo A1 - Fleischhammel, Petra A1 - Schapp, Andrea A1 - Schümberg, Sabine A1 - Uhlmann, Wilfried A1 - Seiler, D. A1 - Zimmermann, K. T1 - "Perspektive See" : zum Stand der Entwicklung der Wasserbeschaffenheit in den Lausitzer Bergbaufolgeseen, Abschlussbericht Projektzeitraum 2008 - 2012 Y1 - 2012 UR - https://www.lmbv.de/index.php/Publ_Lausitz.html ER -