Das Projekt "Sub project: Hydrochemical and hydraulic properties of the continental upper crust at the KTB site" wird vom Umweltbundesamt gefördert und von Regierungspräsidium Freiburg, Abteilung 9 - Landesamt für Geologie, Rohstoffe und Bergbau durchgeführt. A constant rate pumping test of one year duration is planed to be carried out in the 4.0 km deep pilot hole of KTB. Watertable fluctuations in the pilot borehole and in the 9.1 km deep main borehole will be monitored as well. A wealth of data (pumping rate, watertable/ pressure, temperature, salinity/electrical conductivity, water samples,....) will become available, some even online. The first objective of the proposed project is to determine the flow system (type of aquifer model). From this deduced hydraulic model follow the hydraulic characteristics (such as: transmissivity, storage coefficient, fracture lengt/ width/aperture, permeability of fractures and matrix,....) describing the properties of the crystalline basement rocks in vicinity of the KTB pilot- and main hole. The length of the expect test radius is some 1000 m. The proposed project intends also to determine the degree of the hydraulic connection between the two holes (having a depth difference of 5.1 km). Additional information, such as water analyses, will be needed in interpreting the hydraulic data. A second major objective is the modelling of water-rock interaction (WRI) processes using the chemical data of KTB fluids. In particular the time series of chemical data will be used to model the kinetic and time dependent processes. We expect as well to see some breakthroughs of 'fresh, clean' crystalline basement water and another breakthrough resulting from fluid stored in the main hole and its surrounding.
Das Projekt "Sub project: Mass transfer, aging and reactions at NAPL interfaces in porous media" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Zentrum für Angewandte Geowissenschaften - Umweltmineralogie und Umweltchemie durchgeführt. Release of non-aqueous phase liquids (NAPLs) into natural porous media is a widespread environmental problem. Transfer of pollutants across the NAPL-water phase boundary determines both the extent of groundwater contamination as well as the persistence of residual NAPL phases in porous media. Previous research has shown that NAPL-water interfaces are subject to 'aging' phenomena in aqueous environments, e.g., development of skin-like viscous films. However, surprisingly litte is known about the factors and mechanisms that control such film formation of NAPLs in aqueous porous media and about the effects of such films on mass transfer of organic contaminants from the NAPL to the aqueus phase. In the proposed project we will address these knowledge gaps in order to (i) achieve a process based understanding of reactions and environmental conditions leading to the formation of viscous phase boundaries of NAPLs in porous media (aging) and to (ii) develop and vali-date a physical model of such boundary layers to quantify time-dependent interfacial phenomena in multi-component NAPL-water systems (mass transfer). To this end we will carry out batch and flow-through experiments with model and real NAPLs in water and aqueous porous media and make intense use of chemical probe techniques. We will utilize chemical and rheological analysis, microscopic process modeling and, in cooperation with partners within the research group, we will apply new designs of spectroscopic and electrochemical tools for spatially highly resolved investigations of the interface as well as contribute to reactive transport modeling at NAPL-contaminated porous media.
Das Projekt "Extreme events in the past and future - A comparative assessment for the Hai He river and the Poyang lake basins" wird vom Umweltbundesamt gefördert und von Rheinische Friedrich-Wilhelms-Universität Bonn, Meteorologisches Institut durchgeführt. The impact of future climate change on land-use and water resource management is strongly dependent on the related changes in weather extremes. The future can only be assessed by the use of global climate models, which currently lack the necessary spatial resolution to represent such events. Moreover, global climate models are not able to incorporate all processes leading to extremes because of their low resolution. Thus downscaling of such runs is necessary, and only dynamical downscaling with high-resolution regional models is able to catch the necessary non-linear processes and process chains leading to extremes. The goal of this joint proposal is to provide estimates including their uncertainties of the behaviour of extreme weather events impacting land-use and water management for the 21st century for two climatically very different catchments, namely the Hai He river and the Poyang lake basins. To this goal we will first analyse the past of extreme events in both regions on the basis of observations and reanalysis data sets using state of the art extreme value statistics. Dynamical downscaling of global climate runs will be performed in order to evaluate the future of extreme events in the catchments. This necessitates first an evaluation of simulations of the current climate and its extremes by comparison with observations on a statistical basis. This will enable us to use the most appropriate regional climate model and to select the parametrisation setup most suitable for both regions, which might be different. While the Chinese partners will provide the observation data sets and perform the dynamical downscaling of global climate runs, the German partners will install the dynamical downscaling procedure at the Chinese partner institute, and generate the statistics of extremes both from observations and the simulations. The evaluation towards trends and uncertainties will be performed in close cooperation.
Das Projekt "Methane Emissions from Impounded Rivers: A process-based study at the River Saar" wird vom Umweltbundesamt gefördert und von Rheinland-Pfälzische Technische Universität Kaiserslautern-Landau, Institut für Umweltwissenschaften durchgeführt. Methane emissions from inland water bodies are of growing global concern since surveys revealed high emissions from tropical reservoirs and recent studies showed the potential of temperate water bodies. First preliminary studies at the River Saar measured fluxes that exceed estimates used in global budgets by one order of magnitude. In this project we will investigate the fluxes and pathways of methane from the sediment to the surface water and atmosphere at the River Saar. In a process-based approach we will indentify and quantify the relevant environmental conditions controlling the potential accumulation of dissolved methane in the water body and its release to the atmosphere. Field measurements, complemented by laboratory experiments and numerical simulations, will be conducted on spatial scales ranging from the river-basin to individual bubbles. We will further quantify the impact of dissolved methane and bubble fluxes on water quality in terms of dissolved oxygen. Special emphasize will be put on the process of bubble-turbation, i.e. bubble-mediated sediment-water fluxes. The project aims at serving as a reference study for assessing methane emissions from anthropogenically altered river systems.
Das Projekt "Sub project: Fluid injection test of the SE2-fault system at the KTB-VB (operation, co-ordination, seismic and hydraulic signals in KTB-HB)" wird vom Umweltbundesamt gefördert und von Helmholtz-Zentrum Potsdam Deutsches GeoForschungsZentrum durchgeführt. The Kontinentale Tiefbohrprogramm der Bundesrepublik Deutschland (KTB) was enormously successful. It has revealed a wealth of geoscientific data and new results of unrivalled quality and broadness. However, several of the main objectives have only been marginally investigated, and the scientific potential of the two KTB boreholes, the 4.0 km deep pilot hole (KTB-VB) and the 9.1 km deep main hole (KTB-HB) has by no means fully exploited. The general aim of this and accompanying projects is to study energy and fluid transport processes in continental fault systems at the KTB drill site. For that purpose it is proposed to carry out a fluid production test during a period of 12 months in the KTB-VB. During the test various geophysical, hydraulic and geochemical parameters will be monitored in real-time. Samples of uncontaminated deep seated crustal fluids and gases will be taken regularly for further detailed geochemical, geobiological and isotopic investigations. Data and samples will be provided to several research groups from different institutions for further detailed evaluation. Within this project, the operational work, and tasks of the science team will be co-ordinated, also geochemistry and isotopic composition of crustal gases will be investigated in detail.
Das Projekt "Space-time modelling of rainfall using Copulas - a quasi meta-gaussian approach" wird vom Umweltbundesamt gefördert und von Universität Stuttgart, Institut für Wasser- und Umweltsystemmodellierung durchgeführt. Stochastic space time modelling of precipitation is a scientific challenge with great practical importance. There are two key challenges: Firstly, rainfall is highly variable in its spatial and temporal distribution. Secondly, within a rain-field there are locations where the rainfall intensity is zero (a property referred to as 'intermittence'). The practical importance lies in the fact that spatially distributed rainfall fields are of key importance for designers and planners for flood protection. Moreover, the field of weather forecasting is more and more interested in correct spatially-distributed rainfall fields to enhance weather forecasts. Currently, there are no methods available which take these two properties adequately into account. We are suggesting the development of a method that can describe the spatial and temporal variability of rain fields and correctly takes intermittence into account. The purpose of this proposal is to develop a novel methodology for multisite precipitation modelling which is based on Copulas. Copulas are the method of choice to describe spatial and temporal dependence structures, because Copulas allow to describe such a dependence in its purest form. This methodology should be applied to different climatic conditions in Germany and in South-Africa. Different climatic conditions imply a different spatial and temporal distribution of rainfall, and applying the proposed model there will be an ultimate test for the model. First step of the development is to create and test the model for the daily time scale using conventional observations. Subsequently, the model will be tested for smaller time steps, as small as one hour. The model should serve both as a precipitation generating procedure and as the basis for an interpolator and a conditional simulator. The research is planned to be conducted bilaterally in Germany and South Africa and is aimed to complement present research activities both on Copulas and precipitation modelling.
Das Projekt "A Scientific Review of the Global Water System" wird vom Umweltbundesamt gefördert und von Universität Kassel, Center for Environmental Systems Research durchgeführt. One of the important new insights of global environmental research has been the recognition of the existence of a global water system. This concept expands the long-accepted concept of the global physical water cycle to encompass biogeochemical, ecological and socioeconomic components. The recent launching of the Global Water System Project (GWSP) by the major global research organizations is a strong signal from the scientific community that key questions about this system need to be urgently studied. The objective of this one year project is to conduct a scientific review of the concept of the global water system by compiling and evaluating existing scientific literature and data bases and carrying out discussions with scientific experts. The review will identify key unresolved research questions. The scientific review will be divided into three parts (I) Describing the physical, biogeochemical, ecological and socio-political aspects of the global water system, (II) Elaborating cross-cutting linkages in the global water system, (III) Identifying major unresolved questions & research priorities. To ensure that the perspectives of developing countries are also taken into account, the Antragssteiler proposes to spend 6 months out of the 12-month project at the National Institute of Advanced Studies in Bangalore. This will be a fully independent (eigenständiges) and alone-standing project conducted within the framework of the GWSP (of which the Antragssteiler is Co-Chair). It is expected that the scientific review will make a major contribution to setting priorities in global water research over the coming years.
Das Projekt "Pockmark like structures in Lake Constance and their effects on methane emission from large lakes" wird vom Umweltbundesamt gefördert und von Stiftung Alfred-Wegener-Institut für Polar- und Meeresforschung in der Helmholtz-Gemeinschaft, Biologische Anstalt Helgoland (Institut BAH) durchgeführt. The role of lakes in the global methane budget seems to be more important than previously thought. However, the sources and the sinks of this climate active gas in large lakes are still quite unknown. Beside diffusive flux or ebullition due to high microbiological methane production, another potentially important methane source is the emission of fluids and gas from the deeper geosphere, such as methane seeps or pockmarks. Pockmarks are depressions at the sediment surface, often characterized by fluid flow and sites of enhanced methane release. Numerous pockmarks have been described for the marine environment, but pockmarks in limnic systems are rather unknown, as well as their associated geological, chemical and biological processes. In Lake Constance (southern Germany) pockmark like structures have been discovered recently. In a preliminary survey in 2005, we were able to observe methane ebullition and increased methane concentrations in the adjacent water column at these pockmarks. The objectives of this study are (1) to locate and to describe the pockmark areas in Lake Constance, (2) to identify the mechanisms responsible for the formation of pockmarks in Lake Constance, (3) to identify the sources of methane and (4) to quantify the fluxes of methane from the lake floor and their temporal variability.
Das Projekt "Sub project: Electron transfer reactions at iron mineral surfaces in the presence of organic sorbates" wird vom Umweltbundesamt gefördert und von Universität Tübingen, Zentrum für Angewandte Geowissenschaften - Umweltmineralogie und Umweltchemie durchgeführt. Redox reactions at iron mineral surfaces play an important role in determining the overall biogeochemical milieu in anoxic groundwater systems. Previous studies have shown that oxidation of sorbed ferrous iron at mineral phases may cause remodelling of the mineralwater interphase and thus may affect electron transfer processes in anoxic aquifers. In the first funding period, we studied in detail how and at which conditions oxidation of ferrous iron at mineral surfaces affects electron transfer processes. Using carbon tetrachloride (CCl4) as model oxidant, we could further demonstrate, that the proposed reactive tracer approach, which is based on changes of the stable isotopic composition of model oxidants, could be successfully applied to characterize the surface reactivity and dynamics of surface bound Fe(II) species at iron(III)hydroxides. Up to date, process based studies on surface mediated transformation of redox active solutes in iron mineral systems have been conducted primarily in model systems devoid of natural organic matter. In natural systems, however, mineral surfaces are inevitably in contact with OM. Sorbed DOM is likely to affect heterogeneous electron transfer processes due to its interactions with iron both in aqueous solution and at the mineral surface. On one hand, DOM sorption at iron hydroxides may interfere with the formation of reactive Fe(II) surface sites. On the other hand, DOM contain redox active quinone moieties and may act as a mediator enhancing the electron-transfer across the mineral surface. In this follow-up project we propose to investigate the effects of various organic sorbates such as redox-inert organic acids as well as redox-active quinones, humic substances and DOM on electron transfer reactions at iron mineral surfaces. Furthermore, we will investigate the effects of sulfide as additional redox active natural component on DOM-iron interfacial redox processes.
Das Projekt "Der Flusseintrag von Zr, Hf, Nb und Ta in den Ozean und dessen Auswirkung auf die Meerwasser-Hf-Isotopenzusammensetzung" wird vom Umweltbundesamt gefördert und von Jacobs University Bremen gGmbH, Focus Area Health - Physics & Earth Sciences durchgeführt. Flusswasser wird allgemein als Haupteintragsquelle der Partikel-reaktiven Elemente Zr, Hf, Nb und Ta in den Ozean vermutet, trotz spärlicher Datengrundlage. Es fehlt bisher jedoch eine systematische Untersuchung zum Transport dieser Elemente von den Kontinenten in die Ozeane, ebenso wie ein fundiertes Verständnis über den Einfluss geologischer Bedingungen und Umweltbedingungen auf ihr geochemisches Verhalten. Die große black box entlang des Transportweges vom Land zum Meer sind die Ästuare, wo durch die Mischung von Süßwasser und Salzwasser der Eintrag Partikel-reaktiver Elemente in die Ozeane grundlegend modifiziert wird. Diese Studie thematisiert die Verteilung von Zr, Hf, Nb und Ta sowie die Hf-Isotopenzusammensetzung in Flüssen aus borealen und gemäßigten Klimazonen und in glazialen Schmelzwässern, unter Berücksichtigung der Assoziation mit den unterschiedlichen physikalischen Anteilen im Süßwasser, d.h. der partikulären Fracht (größer als 0.2 Mikro m), der kolloidalen Fracht (0.2 Mikro m to 1 KDa) und der echt gelösten (kleiner als 1 KDa) Fracht. Der Netto-Flusseintrag dieser Elemente ins Meer und dessen Einfluss auf die Hf-Isotopenzusammensetzung des Meerwassers sollen durch Mischungsexperimente von Fluss- und Meerwasser untersucht werden. Die komplexe Methodenarbeit umfasst Filtration und Ultrafiltration sowie Anreicherungsschritte. Die Ergebnisse dieser Studie werden unser Verständnis zum Transport von Zr, Hf, Nb, und Ta im Süßwasser und ihren Weg vom Kontinent zum Ozean bei unterschiedlichen geologischen Bedingungen und Umweltbedingungen erweitern. Die Ergebnisse zur Hf-Isotopie werden dazu beitragen, die Rolle der kontinentalen Verwitterung und der Abflussbedingungen bei der Bestimmung der Hf-Isotopenzusammensetzung im Meerwasser besser zu verstehen.
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