Sauter, Martin

[["dc.bibliographiccitation.firstpage","251"],["dc.bibliographiccitation.issue","4"],["dc.bibliographiccitation.journal","Grundwasser"],["dc.bibliographiccitation.lastpage","262"],["dc.bibliographiccitation.volume","19"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:32:14Z"],["dc.date.available","2018-11-07T09:32:14Z"],["dc.date.issued","2014"],["dc.description.abstract","In the presented work the occurrence of organic micro-pollutants is discussed for two karst areas with different geological characteristics and land-use patterns. Within an urban moderately karstified catchment with a large number of local input sources (e.g. contaminated sites, sewer leakages), a greater variety of micro-pollutants is found compared to a rural area. Mostly the concentrations of these compounds decrease below quantification limits before emerging at the spring and can therefore only be detected by a comprehensive network of sampling points. Springs show the presence of micro-pollutants, either recently applied in large amounts or characterized by high persistence. At the outlet of a highly karstified and consequently highly permeable aquifer readily biodegradable compounds are detected. Due to high groundwater flow velocities investigations of micro-pollutants require a highly resolved monitoring. Therefore, beside substance properties, also hydrogeological characteristics affect the spectrum of detectable micro-pollutants."],["dc.identifier.doi","10.1007/s00767-014-0264-6"],["dc.identifier.isi","000345078800003"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/31709"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.issn","1432-1165"],["dc.relation.issn","1430-483X"],["dc.title","Application of organic micro-pollutants for the characterisation of two karst systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","395"],["dc.bibliographiccitation.issue","2"],["dc.bibliographiccitation.journal","Water Research"],["dc.bibliographiccitation.lastpage","402"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Geyer, Tobias"],["dc.date.accessioned","2018-11-07T09:14:02Z"],["dc.date.available","2018-11-07T09:14:02Z"],["dc.date.issued","2012"],["dc.description.abstract","Contamination from untreated wastewater leakage and related bacterial contamination poses a threat to drinking water quality. However, a quantification of the magnitude of leakage is difficult. The objective of this work is to provide a highly sensitive methodology for the estimation of the mass of untreated wastewater entering karst aquifers with rapid recharge. For this purpose a balance approach is adapted. It is based on the mass flow of caffeine in spring water, the load of caffeine in untreated wastewater and the daily water consumption per person in a spring catchment area. Caffeine is a source-specific indicator for wastewater, consumed and discharged in quantities allowing detection in a karst spring. The methodology was applied to estimate the amount of leaking and infiltrating wastewater to a well investigated karst aquifer on a daily basis. The calculated mean volume of untreated wastewater entering the aquifer was found to be 2.2 +/- 0.5 m(3) d(-1) (undiluted wastewater). It corresponds to approximately 0.4% of the total amount of wastewater within the spring catchment. (C) 2011 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Federal Ministry of Education and Research [02WM1081, 02WRS1277A]"],["dc.identifier.doi","10.1016/j.watres.2011.11.003"],["dc.identifier.isi","000299609400014"],["dc.identifier.pmid","22104295"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/27307"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0043-1354"],["dc.title","Caffeine as an indicator for the quantification of untreated wastewater in karst systems"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","112"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.lastpage","123"],["dc.bibliographiccitation.volume","426"],["dc.contributor.author","Doummar, Joanna"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Geyer, Tobias"],["dc.date.accessioned","2018-11-07T09:12:13Z"],["dc.date.available","2018-11-07T09:12:13Z"],["dc.date.issued","2012"],["dc.description.abstract","In a complex environment such as karst systems, it is difficult to assess the relative contribution of the different components of the system to the hydrological system response, i.e. spring discharge. Not only is the saturated zone highly heterogeneous due to the presence of highly permeable conduits, but also the recharge processes. The latter are composed of rapid recharge components through shafts and solution channels and diffuse matrix infiltration, generating a highly complex, spatially and temporally variable input signal. The presented study reveals the importance of the compartments vegetation, soils, saturated zone and unsaturated zone. Therefore, the entire water cycle in the catchment area Gallusquelle spring (Southwest Germany) is modelled over a period of 10 years using the integrated hydrological modelling system Mike She by DHI (2007). Sensitivity analyses show that a few individual parameters, varied within physically plausible ranges, play an important role in reshaping the recessions and peaks of the recharge functions and consequently the spring discharge. Vegetation parameters especially the Leaf Area Index (LAI) and the root depth as well as empirical parameters in the relationship of Kristensen and Jensen highly influence evapotranspiration, transpiration to evaporation ratios and recharge respectively. In the unsaturated zone, the type of the soil (mainly the hydraulic conductivity at saturation in the water retention and hydraulic retention curves) has an effect on the infiltration/evapotranspiration and recharge functions. Additionally in the unsaturated karst, the saturated moisture content is considered as a highly indicative parameter as it significantly affects the peaks and recessions of the recharge curve. At the level of the saturated zone the hydraulic conductivity of the matrix and highly conductive zone representing the conduit are dominant parameters influencing the spring response. Other intermediate significant parameters appear to influence the characteristics of the spring response yet to a smaller extent, as for instance bypass and the parameters alpha in the Van Genuchten relation for soil moisture content curves. (C) 2012 Elsevier B.V. All rights reserved."],["dc.description.sponsorship","Deutscher Akademischer Austausch Dienst (DAAD) [441]"],["dc.identifier.doi","10.1016/j.jhydrol.2012.01.021"],["dc.identifier.isi","000301805000010"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/26902"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0022-1694"],["dc.title","Simulation of flow processes in a large scale karst system with an integrated catchment model (Mike She) - Identification of relevant parameters influencing spring discharge"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","5381"],["dc.bibliographiccitation.issue","16"],["dc.bibliographiccitation.journal","Water Research"],["dc.bibliographiccitation.lastpage","5388"],["dc.bibliographiccitation.volume","46"],["dc.contributor.author","Hillebrand, Olav"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.contributor.author","Geyer, Tobias"],["dc.date.accessioned","2018-11-07T09:04:37Z"],["dc.date.available","2018-11-07T09:04:37Z"],["dc.date.issued","2012"],["dc.description.abstract","Little is known with respect to the attenuation capacity of karst aquifers. Even less is known about the risk posed by emerging micropollutants in these systems. In order to identify the attenuation potential of karst aquifers in-situ and to estimate the risk posed by micropollutants, a dualtracer test was conducted in this study in order to investigate differential transport in the subsurface: The reactive compound caffeine was used as a tracer to indicate the attenuation capacity within the aquifer in-situ. Due to the low limit of quantification, only small amounts of caffeine needed to be injected. To calibrate a model and to visualize the attenuation of caffeine a conservative reference tracer (uranine) is injected simultaneously. The methodology is tested in a well-characterised karst system in southwest Germany. The results indicate a significantly higher attenuation rate than was expected for karst aquifers. The attenuation is decribed as a first-order process. The corresponding half-life is 104 h. This low half-life suggests that a generally assumed low natural attenuation capacity of karst aquifers is unjustified. The observed mass loss of caffeine illustrates the potential of caffeine to be used as reactive tracer for indicating in-situ attenuation capacity within highly hydraulically conductive systems, such as karst aquifers. Due to the high attenuation rate of caffeine it does not pose a threat as a longtime contaminant. In combination with a conservative reference tracer an economical and environmentally benign method is presented in this manuscript for the in-situ determination of the attenuation capacity of highly conductive aquifer systems. (C) 2012 Elsevier Ltd. All rights reserved."],["dc.description.sponsorship","German Federal Ministry of Education and Research [02WRS1277A]"],["dc.identifier.doi","10.1016/j.watres.2012.07.032"],["dc.identifier.isi","000309095800046"],["dc.identifier.pmid","22877878"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/25147"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Pergamon-elsevier Science Ltd"],["dc.relation.issn","0043-1354"],["dc.title","Identification of the attenuation potential of a karst aquifer by an artificial dualtracer experiment with caffeine"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","452"],["dc.bibliographiccitation.issue","3-4"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.lastpage","463"],["dc.bibliographiccitation.volume","348"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Birk, Steffen"],["dc.contributor.author","Liedl, Rudolf"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T11:19:07Z"],["dc.date.available","2018-11-07T11:19:07Z"],["dc.date.issued","2008"],["dc.description.abstract","The estimation of the temporal distribution of recharge in karst aquifers is a challenge due to Large heterogeneities in geometric and hydraulic parameters of the vadose and phreatic zone. This article provides a time-continuous approach for the estimation of inflow into the conduit system of a karst aquifer which consists of the sum of direct recharge and flow from the fissured matrix blocks into the conduit system. The approach employs the first time derivative of the spring hydrograph and the recession coefficient of the conduit system for the determination of this function. The first time derivative of the hydrograph describes the rate of change in spring discharge. It reflects the ratio of inflow to and outflow from the conduit system. The recession coefficient depends on the hydraulic diffusivity, which controls the velocity of the signal transmission through the system. As shown in parameter studies with a simplified serial two-reservoir model, direct recharge into the conduit system clearly dominates the early hydrograph response during recharge events even if the fraction of direct recharge represents just a few percent of total recharge. This behaviour is caused by a large contrast in recession coefficients between conduit system and fissured matrix blocks. The direct recharge component can therefore be separated from the estimated total inflow into the conduit system. Estimation of inflow into the conduit system of the Gallusquelle spring (Swabian Alb, Germany) after a storm event yields similar results as those obtained from parameter studies. The separation of the direct recharge component is in agreement with information from an independent isotope study. The methodology has been further applied to a recharge event initiated by snowmelt. As a result of daily variations of the air temperature, a clearly diurnal cycle of inflow into the conduit system is estimated that is not easily recognizable from the spring hydrograph. The applicability of the proposed methodology requires knowledge about the magnitude of the recession coefficient of the conduit system. The characteristics of the conduit system become also apparent in the rapid transport of tracers. The recession coefficient of the conduit system can, for example, directly be estimated from the reciprocal of the mean tracer travel time. However, for this type of analysis, only tracer experiments, covering the extent of the catchment should be taken into account. For the Gallusquelle catchment the recession coefficient obtained from the tracer experiment corresponds to that obtained from hydrograph recession analysis. The estimated inflow into the conduit system and interpretation of temporal distribution of recharge is therefore based on a plausible and physically based parameter. (c) 2007 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jhydrol.2007.10.015"],["dc.identifier.isi","000252749000018"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/55196"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0022-1694"],["dc.title","Quantification of temporal distribution of recharge in karst systems from spring hydrographs"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","4631"],["dc.bibliographiccitation.issue","6"],["dc.bibliographiccitation.journal","Environmental Science and Pollution Research"],["dc.bibliographiccitation.lastpage","4643"],["dc.bibliographiccitation.volume","22"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T10:00:15Z"],["dc.date.available","2018-11-07T10:00:15Z"],["dc.date.issued","2015"],["dc.description.abstract","This study presents chances and challenges associated with the application of organic micro-pollutants (OMPs) as indicators in karst system characterization. The methodology and options of possible indications were evaluated based on the interpretation of the spatial distribution of 54 compounds in groundwater in combination with a complex geological setting consisting of multiple aquifer horizons and tectonic faults. A high variety of OMPs are released mainly in an urban area leading to concentrations of several nanograms per liter up to micrograms per liter, which are detectable using a high-performance liquid chromatography with subsequent tandem mass spectrometry (HPLC-MS/MS) method. Since characteristic patterns of spatial distribution were repeatedly observed during a 2-year observation period, important criteria of the aforementioned indicator application are fulfilled. Triazoles, compounds with recent high emission rates, could be successfully applied for the identification of flow directions and the delineation of catchment areas. Concentrations and the number of OMPs are believed to be dependent on properties of covering rock layers. Therefore, OMPs can also be used as a validation tool for vulnerability mapping. Compounds, such as triazines, persistent in the system for more than two decades, demonstrate the interaction between different parts of the aquifer system and the hydraulic characteristics of a tectonic fault zone. Such indicator potentials complement those of artificial tracer tests. Point sources of OMPs and their impact on groundwater could be identified qualitatively. In combination with the interpretation of the geological setting, the distribution of OMPs provides essential information for the development of a conceptual hydrogeological model."],["dc.identifier.doi","10.1007/s11356-014-3676-z"],["dc.identifier.isi","000350572500054"],["dc.identifier.pmid","25323407"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/37761"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Springer"],["dc.publisher.place","Heidelberg"],["dc.relation.issn","1614-7499"],["dc.relation.issn","0944-1344"],["dc.title","Evaluation and application of organic micro-pollutants (OMPs) as indicators in karst system characterization"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","438"],["dc.bibliographiccitation.journal","The Science of The Total Environment"],["dc.bibliographiccitation.lastpage","445"],["dc.bibliographiccitation.volume","443"],["dc.contributor.author","Reh, Roland"],["dc.contributor.author","Licha, Tobias"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Noedler, Karsten"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:29:09Z"],["dc.date.available","2018-11-07T09:29:09Z"],["dc.date.issued","2013"],["dc.description.abstract","Fifty-four different organic micro-pollutants (OMPs) including pharmaceuticals, pesticides, corrosion inhibitors and other typical wastewater compounds such as caffeine are repeatedly analyzed in approximately fifty groundwater observation points in a complex faulted and fractured carbonate aquifer system consisting of three spring catchment areas. With the applied HPLC-MS/MS method, achieving method quantification limits (MQL) of 12-28 ng L-1, forty-four of the OMPs are detected in groundwater. Regarding the vertical distribution in the aquifer system the highest variety of OMPs occurs in the shallow aquifer. Most frequently detected compounds are atrazine together with the metabolites of several triazines, desethylatrazine (DEA) and desisopropylatrazine (DIA), the corrosion inhibitors 1H-benzotriazole and tolytriazoles and as pharmaceutical residues the anti-epileptic drug carbamazepine as well as the analgesic drug phenazone. Median OMP concentrations are in the range of 20-40 ng L-1 with occasionally and locally higher concentrations of up to 6000 ng L-1. Defined combinations of OMPs occur repeatedly in the same observation wells and allow to distinguish different input functions. The comparison of detection frequency with the number of prescribed doses gives information about the specific persistence of pharmaceuticals. The analgesic phenazone exhibits a peculiar high detection frequency, although it is recently not prescribed in significant amounts. The detection of the estrogen antagonist tamoxifen (6-17 ng L-1) in a groundwater flow system is reported for the first time. (C) 2012 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.scitotenv.2012.11.005"],["dc.identifier.isi","000315559900046"],["dc.identifier.pmid","23208277"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/30949"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","0048-9697"],["dc.title","Occurrence and spatial distribution of organic micro-pollutants in a complex hydrogeological karst system during low flow and high flow periods, results of a two-year study"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","750"],["dc.bibliographiccitation.journal","Journal of Hydrology"],["dc.bibliographiccitation.lastpage","763"],["dc.bibliographiccitation.volume","511"],["dc.contributor.author","Schmidt, Sebastian"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Guttman, Joseph"],["dc.contributor.author","Marei, Amer"],["dc.contributor.author","Ries, Fabian"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T09:41:13Z"],["dc.date.available","2018-11-07T09:41:13Z"],["dc.date.issued","2014"],["dc.description.abstract","The conduit system of mature karstified carbonate aquifers is typically characterised by a high hydraulic conductivity and does not impose a major flow constriction on catchment discharge. As a result, discharge at karst springs is usually flashy and displays pronounced peaks following recharge events. In contrast, some karst springs reported in literature display a discharge maximum, attributed to reaching the finite discharge capacity of the conduit system (flow threshold). This phenomenon also often leads to a non-standard recession behaviour, a so called \"convex recession\", i.e. an increase in the recession coefficient during flow recession, which in turn might be used as an indicator for conduit restricted aquifers. The main objective of the study is the characterisation and modelling of those hydrogeologically challenging aquifers. The applied approach consists of a combination of hydrometric monitoring, a spring hydrograph recession and event analysis, as well as the setup and calibration of a non-linear reservoir model. It is demonstrated for the Auja spring, the largest freshwater spring in the Lower Jordan Valley. The semi-arid environment with its short but intensive precipitation events and an extended dry season leads to sharp input signals and undisturbed recession periods. The spring displays complex recession behaviour, exhibiting exponential (coefficient alpha) and linear (coefficient beta) recession periods. Numerous different recession coefficients a were observed: similar to 0.2 to 0.8 d(-1) (presumably main conduit system), 0.004 d(-1) (fractured matrix), 0.0009 d(-1) (plateau caused by flow threshold being exceeded), plus many intermediate values. The reasons for this observed behaviour are the outflow threshold at 0.47 m(3) s(-1) and a variable conduit-matrix cross-flow in the aquifer. Despite system complexity, and hence the necessity of incorporating features such as a flow threshold, conduit-matrix cross-flow, and a spatially variable soil/epikarst field capacity, the developed reservoir model is regarded as relatively simplistic. As a number of required parameters were calculated from the hydrogeological analysis of the system, it requires only six calibration parameters and performs well for the highly variable flow conditions observed. Calculated groundwater recharge in this semi-arid environment displays high interannual variability. For example, during the 45-year simulation period, only five wet winter seasons account for 33% of the total cumulative groundwater recharge. (C) 2014 Elsevier B.V. All rights reserved."],["dc.identifier.doi","10.1016/j.jhydrol.2014.02.019"],["dc.identifier.isi","000335274900065"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/33682"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Elsevier Science Bv"],["dc.relation.issn","1879-2707"],["dc.relation.issn","0022-1694"],["dc.title","Characterisation and modelling of conduit restricted karst aquifers - Example of the Auja spring, Jordan Valley"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.firstpage","2283"],["dc.bibliographiccitation.issue","7"],["dc.bibliographiccitation.journal","Hydrogeology Journal"],["dc.bibliographiccitation.lastpage","2295"],["dc.bibliographiccitation.volume","26"],["dc.contributor.author","Doummar, Joanna"],["dc.contributor.author","Margane, Armin"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2020-12-10T14:11:08Z"],["dc.date.available","2020-12-10T14:11:08Z"],["dc.date.issued","2018"],["dc.identifier.doi","10.1007/s10040-018-1754-x"],["dc.identifier.eissn","1435-0157"],["dc.identifier.issn","1431-2174"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/70972"],["dc.language.iso","en"],["dc.notes.intern","DOI Import GROB-354"],["dc.title","Assessment of key transport parameters in a karst system under different dynamic conditions based on tracer experiments: the Jeita karst system, Lebanon"],["dc.title.alternative","Evaluation des paramètres clefs du transport dans un système karstique sous différentes conditions dynamiques à partir des essais de traçage: le système karstique de Jeita, Liban"],["dc.title.alternative","Evaluación de parámetros de transporte claves en un sistema kárstico bajo diferentes condiciones dinámicas basadas en experimentos con trazadores: el sistema kárstico de Jeita, Líbano"],["dc.title.alternative","Avaliação dos principais parâmetros em um sistema cárstico sob diferentes condições dinâmicas baseado em experimentos com traçadores: sistema cárstico Jeita, Líbano"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dspace.entity.type","Publication"]]

[["dc.bibliographiccitation.artnumber","W11503"],["dc.bibliographiccitation.journal","Water Resources Research"],["dc.bibliographiccitation.volume","47"],["dc.contributor.author","Reimann, Thomas"],["dc.contributor.author","Geyer, Tobias"],["dc.contributor.author","Shoemaker, W. Barclay"],["dc.contributor.author","Liedl, Rudolf"],["dc.contributor.author","Sauter, Martin"],["dc.date.accessioned","2018-11-07T08:49:58Z"],["dc.date.available","2018-11-07T08:49:58Z"],["dc.date.issued","2011"],["dc.description.abstract","Well-developed karst aquifers consist of highly conductive conduits and a relatively low permeability fractured and/or porous rock matrix and therefore behave as a dual-hydraulic system. Groundwater flow within highly permeable strata is rapid and transient and depends on local flow conditions, i.e., pressurized or nonpressurized flow. The characterization of karst aquifers is a necessary and challenging task because information about hydraulic and spatial conduit properties is poorly defined or unknown. To investigate karst aquifers, hydraulic stresses such as large recharge events can be simulated with hybrid (coupled discrete continuum) models. Since existing hybrid models are simplifications of the system dynamics, a new karst model (ModBraC) is presented that accounts for unsteady and nonuniform discrete flow in variably saturated conduits employing the Saint-Venant equations. Model performance tests indicate that ModBraC is able to simulate (1) unsteady and nonuniform flow in variably filled conduits, (2) draining and refilling of conduits with stable transition between free-surface and pressurized flow and correct storage representation, (3) water exchange between matrix and variably filled conduits, and (4) discharge routing through branched and intermeshed conduit networks. Subsequently, ModBraC is applied to an idealized catchment to investigate the significance of free-surface flow representation. A parameter study is conducted with two different initial conditions: (1) pressurized flow and (2) free-surface flow. If free-surface flow prevails, the systems is characterized by (1) a time lag for signal transmission, (2) a typical spring discharge pattern representing the transition from pressurized to free-surface flow, and (3) a reduced conduit-matrix interaction during free-surface flow."],["dc.description.sponsorship","Deutsche Forschungsgemeinschaft (DFG) [LI 727/11-1, SA 501/24-1]"],["dc.identifier.doi","10.1029/2011WR010446"],["dc.identifier.isi","000296622300002"],["dc.identifier.uri","https://resolver.sub.uni-goettingen.de/purl?gro-2/21580"],["dc.notes.status","zu prüfen"],["dc.notes.submitter","Najko"],["dc.publisher","Amer Geophysical Union"],["dc.relation.issn","0043-1397"],["dc.title","Effects of dynamically variable saturation and matrix-conduit coupling of flow in karst aquifers"],["dc.type","journal_article"],["dc.type.internalPublication","yes"],["dc.type.peerReviewed","yes"],["dc.type.status","published"],["dspace.entity.type","Publication"]]