TY - CHAP A1 - Brück, Yasemine A1 - Pohle, Ina A1 - Keuler, Klaus A1 - Schaller, Eberhard A1 - Hinz, Christoph T1 - Do mining lakes in the Lusatian Lignite mining region (Eastern Germany) affect regional precipitation patterns? T2 - European Geosciences Union, General Assembly 2016, Vienna, Austria N2 - Due to the flooding of former open-pit mines, Europe’s largest artificial lake district is created in Eastern Germany. Between 1990 and 2006 more than 80 km² of new lakes have already been formed. These large-scale land cover changes may impact regional meteorological characteristics, therefore it is of interest, whether effects of the mining lakes can already be observed. We especially focus on whether the evaporation from the mining pit lakes leads to a higher precipitation on their lee side. To detect changes in the precipitation patterns, we analysed daily precipitation data (1980-2014) of 25 stations in an area of 10 000 km² widely around the lake district. Under the assumption that the influences of the lakes should be detectable either directly as trends in the observed data or as a deviation from a general measure for precipitation we combined statistical tests and principal component analysis (PCA). We applied pre-whitening Mann-Kendall tests to detect precipitation trends and Mann-Whitney tests to detect differences between split samples (before and after the flooding of most of the lakes). The PCA was applied based on the correlation matrix of daily precipitation at the different stations. As the daily precipitation can sufficiently be explained by the first five principal components, the recombination of these five principal components was used as a general measure of precipitation in the region. By regression trees (random forests) a relation between the eigenvectors of the first five principal components and physiogeographic characteristics of the stations (e.g. altitude) was shown. Both the observed data and the deviations between the measurements and the recombination of the first five principal components showed divergent trends with high spatial variability and also interannual variability, but a pattern consistent with the lee side of the lake could not be detected. Therefore, it has been demonstrated that the emerging lakes had no influence on the daily precipitation at the stations considered in this study. This may be explained by the coarse spatial and also temporal resolution of precipitation measurements. Still, the approach presented here can be applied to (i) detect changes in the spatial pattern of climate variables by a combination of statistical tests and PCA and (ii) to analyse the relationships between such changes and physiogeographic characteristics by regression trees. Y1 - 2016 UR - http://meetingorganizer.copernicus.org/EGU2016/EGU2016-7663.pdf N1 - EGU2016-7663 PB - European Geophysical Society CY - Katlenburg-Lindau 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 - CHAP A1 - Zaplata, Markus K. 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 - CHAP A1 - Maurer, Thomas A1 - Trujillo Siliézar, Carlos Gustavos A1 - Oeser, Anne A1 - Pohle, Ina A1 - Hinz, Christoph T1 - A methodology for investigating interdependencies between measured throughfall, meteorological variables and canopy structure on a small catchment T2 - European Geosciences Union, General Assembly 2016, Vienna, Austria N2 - In evolving initial landscapes, vegetation development depends on a variety of feedback effects. One of the less understood feedback loops is the interaction between throughfall and plant canopy development. The amount of throughfall is governed by the characteristics of the vegetation canopy, whereas vegetation pattern evolution may in turn depend on the spatio-temporal distribution of throughfall. Meteorological factors that may influence throughfall, while at the same time interacting with the canopy, are e.g. wind speed, wind direction and rainfall intensity. Our objective is to investigate how throughfall, vegetation canopy and meteorological variables interact in an exemplary eco-hydrological system in its initial development phase, in which the canopy is very heterogeneous and rapidly changing. For that purpose, we developed a methodological approach combining field methods, raster image analysis and multivariate statistics. The research area for this study is the Hühnerwasser (‘Chicken Creek’) catchment in Lower Lusatia, Brandenburg, Germany, where after eight years of succession, the spatial distribution of plant species is highly heterogeneous, leading to increasingly differentiated throughfall patterns. The constructed 6-ha catchment offers ideal conditions for our study due to the rapidly changing vegetation structure and the availability of complementary monitoring data.Throughfall data were obtained by 50 tipping bucket rain gauges arranged in two transects and connected via a wireless sensor network that cover the predominant vegetation types on the catchment (locust copses, dense sallow thorn bushes and reeds, base herbaceous and medium-rise small-reed vegetation, and open areas covered by moss and lichens). The spatial configuration of the vegetation canopy for each measurement site was described via digital image analysis of hemispheric photographs of the canopy using the ArcGIS Spatial Analyst, GapLight and ImageJ software. Meteorological data from two on-site weather stations (wind direction, wind speed, air temperature, air humidity, insolation, soil temperature, precipitation) were provided by the ‘Research Platform Chicken Creek’. Data were combined and multivariate statistical analysis (PCA, cluster analysis, regression trees) were conducted using the R-software to i) obtain statistical indices describing the relevant characteristics of the data and ii) to identify the determining factors for throughfall intensity. The methodology is currently tested and results will be presented. Preliminary evaluation of the image analysis approach showed only marginal, systematic deviation of results for the different software tools applied, which makes the developed workflow a viable tool for canopy characterization. Results from this study will have a broad spectrum of possible applications, for instance the development / calibration of rainfall interception models, the incorporation into eco-hydrological models, or to test the fault tolerance of wireless rainfall sensor networks. Y1 - 2016 UR - http://meetingorganizer.copernicus.org/EGU2016/EGU2016-4729-1.pdf N1 - EGU2016-4729-1 PB - European Geophysical Society CY - Katlenburg-Lindau ER - TY - GEN A1 - Pohle, Ina A1 - Koch, Hagen A1 - Zimmermann, Kai A1 - Gädeke, Anne A1 - Claus, Thomas A1 - Uhlmann, Wilfried A1 - Kaltofen, Michael A1 - Redetzky, Michael A1 - Schramm, Martina A1 - Müller, Fabian A1 - Schoenheinz, Dagmar A1 - Grünewald, Uwe T1 - Analyse von Wassermenge und Wasserbeschaffenheit für Klima- und Bewirtschaftungsszenarien: Aufbau und Nutzung einer Modellkaskade für das Spreeeinzugsgebiet T2 - Hydrologie und Wasserbewirtschaftung N2 - Klimaänderungen und sozioökonomische Entwicklungen können Konsequenzen für die Wassermengenbewirtschaftung und die Wasserbeschaffenheit nach sich ziehen. Zur Abschätzung der Auswirkungen regionaler Entwicklungen wurde in dieser Studie eine Modellkaskade aus (i) den hydrologischen Modellen SWIM und EGMO, (ii) dem Langfristbewirtschaftungsmodell WBalMo und (iii) dem Wassergütemodell GGM entwickelt, implementiert und angewandt. Die Modellkaskade bietet zudem die Möglichkeit,Anpassungsoptionen der Wassermengen– und –gütebewirtschaftung einzubeziehen. Als Untersuchungsgebiet dient das Einzugsgebiet der Spree, in dem in Folge des jahrzehntelangen Braunkohlebergbaus und dessen Rückgangs seit den 1990er Jahren vielfältige Herausforderungen hinsichtlich Wassermenge und –beschaffenheit bestehen (z. B. niedrige pH-Werte in den Tagebauseen, hohe Sulfatkonzentrationen in den Tagebauseen und Vorflutern). Die grundlegende Fragestellung ist, ob sich die bestehenden Wassermengen– und beschaffenheitsprobleme unter zukünftig potenziell trockeneren Bedingungen verschärfen bzw. wie sie durch Anpassungsmaßnahmen gelindert werden können. Als klimatischer Antrieb der Modellkaskade werden stochastisch generierte Zeitreihen (Realisierungen) des Regionalen Klimamodells STAR genutzt. Die Realisierungen des Szenarios STAR 0K werden im Sinne einer Referenzvariante der rezenten klimatischen Bedingungen verwendet, um die Konsequenzen des Rückgangs von Bergbauaktivitäten separat zu betrachten. Zur Ermittlung der Sensitivität der Wasserressourcen gegenüber einer potenziell trockeneren Zukunft dient das Szenario STAR 2K, bei dem eine weitere Erhöhung der Jahresmitteltemperatur um 2 K sowie im Mittel eine Abnahme des Jahresniederschlages projiziert wird. Die Betrachtung der sozioökonomischen Entwicklung der Region wird anhand eines Bewirtschaftungsszenarios betrachtet, welches von einem weiteren Rückgang der Bergbauaktivitäten in der Region ausgeht. Im Verlauf des Zeitraums 2018 2052 zeigen sich im Szenario STAR 0K nur geringe Auswirkungen auf das natürliche Wasserdargebot, die bewirtschafteten Abflüsse gehen durch sinkende Sümpfungswassereinleitungen leicht zurück. Im Szenario STAR 2K geht das natürliche Wasserdargebot zurück und die wasserwirtschaftlichen Speicher werden stärker in Anspruch genommen. Die bewirtschafteten Abflüsse in der Region sinken, was negative Konsequenzen für die Erfüllung von Nutzeransprüchen nach sich zieht. Die Wahrscheinlichkeit, dass die Tagebauseen wiederversauern und die Sulfatkonzentrationen ansteigen, nimmt im Szenario STAR 2K im Vergleich zu STAR 0K zu. Wasserwirtschaftliche Anpassungsoptionen wurden hinsichtlich ihrer Konsequenzen für Wassermenge und beschaffenheit analysiert. Durch die Überleitung von Wasser aus der Elbe können die Wassermengen und beschaffenheitsprobleme gelindert werden. Die In Lake Neutralisation von Tagebauseen kann lokale Probleme der Wasserbeschaffenheit mindern. KW - Wasserbewirtschaftung KW - Wasserqualität KW - Klimawandel KW - Modellkaskade KW - Braunkohlebergbau Y1 - 2016 U6 - https://doi.org/10.5675/HyWa_2016,3_2 VL - 60 IS - 3 SP - 176 EP - 195 ER - TY - CHAP A1 - Pohle, Ina A1 - Hu, Yuzhu A1 - Schaaf, Wolfgang A1 - Gerwin, Werner A1 - Hinz, Christoph T1 - Hydrogeochemical signatures of catchment evolution – the role of calcium and sulphate release in the constructed Hühnerwasser (“Chicken Creek”) catchment T2 - European Geosciences Union, General Assembly 2016, Vienna, Austria N2 - The constructed Hühnerwasser (“Chicken Creek”) catchment is an ecohydrological system in an initial state of development. The catchment with an area of 6 ha was built up from quaternary sediments in the post-mining landscape of Lusatia in Eastern Germany and serves as a critical zone observatory for detecting ecosystem transition. The soil substrate is characterized as sands to loamy sands with low carbonate contents but significant amounts of gypsum in the sediments of the catchment. The catchment undergoes a strong transition from an abiotic system in the initial years to a system with growing influence of biota. Concerning the hydrology, a regime shift from surface runoff to groundwater flow dominated processes is significant. It is of interest, whether the catchment transition is also reflected by hydrogeochemical indicators. We assume gypsum dissolution as dominant process at the catchment scale. In order to investigate the hydrogeochemical evolution of the catchment we analysed electric conductivity, calcium and sulphate concentrations and pH-values of biweekly composite samples from 2007-2013 of the atmospheric deposition, of runoff and soil water. The two observation points in the flowing water represent surface runoff and groundwater discharge respectively. Soil water has been analysed at four soil pits in three depths. The monitoring data were provided by the Research Platform Chicken Creek. From the macroscopic data analysis we found an exponential decay of the electric conductivity, calcium and sulphate concentrations in the flowing waters and some of the soil pits. In the flowing water, the decrease slope of the electric conductivity and the calcium and sulphate concentrations is almost identical. The calcium / sulphate molar ratio as an indicator of gypsum dissolution is almost equal to one up to 2010, afterwards more calcium than sulphate is released. The pH-values in the flowing and soil water are generally higher than in the atmospheric deposition, they do show variabilites but no trend behaviour. The time series analyses showed that the interannual variability of the hydrogeochemical properties is less pronounced in the first years of ecosystem development than in the later years. This leads to the conclusion, that in the first years, gypsum dissolution is the major source for calcium and sulphate in the soil and the flowing waters. The increasing interannual variability and changes in the calcium / sulphate ratio in the later years might be interpreted as hydrogeochemical response to the development of vegetation and acidification due to the development of the rhizosphere. Y1 - 2016 UR - http://meetingorganizer.copernicus.org/EGU2016/EGU2016-7726-1.pdf N1 - EGU2016-7726-1 PB - European Geophysical Society CY - Katlenburg-Lindau ER -