Michael Dietze

University of Tuebingen, Tübingen, Baden-Württemberg, Germany

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Publications (4)7.56 Total impact

  • Michael Dietze · Peter Dietrich
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    ABSTRACT: Detailed information on vertical variations in hydraulic conductivity (K) is essential to describe the dynamics of groundwater movement at contaminated sites or as input data used for modeling. K values in high vertical resolution should be determined because K tends to be more continuous in the horizontal than in the vertical direction. To determine K in shallow unconsolidated sediments and in the vertical direction, the recently developed direct-push injection logger can be used. The information obtained by this method serves as a proxy for K and has to be calibrated to obtain quantitative K values of measured vertical profiles. In this study, we performed direct-push soil sampling, sieve analyses and direct-push slug tests to obtain K values in vertical high resolution. Using the results of direct-push slug tests, quantitative K values obtained by the direct-push injection logger could be determined successfully. The results of sieve analyses provided lower accordance with the logs due to the inherent limitations of the sieving method.
    No preview · Article · Aug 2011 · Ground Water
  • Michael Dietze · Peter Dietrich
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    ABSTRACT: Measuring contaminant flow rates at control cross sections is the most accurate method to evaluate natural attenuation processes in the saturated subsurface. In most instances, point scale measurement is the method of choice due to practical reasons and cost factors. However, at many field sites, the monitoring network is too sparse for a reliable estimation of contaminant and groundwater flow rates. Therefore, integral pumping tests have been developed as an alternative. In this study, we compare mass flow rates obtained by integral pumping test results and point scale data. We compare results of both methods with regard to uncertainties due to estimation errors and mass flow estimations based on two different point scale networks. The differences between benzene and groundwater flow rate estimates resulting from point scale samples and integral pumping tests were 6.44% and 6.97%, respectively, demonstrating the applicability of both methods at the site. Point scale-based data, especially with use of cost efficient Direct-Push technique, can be applied to show the contaminant distribution at a site and may be followed by a denser point scale network or an integral method. Nevertheless, a combination of both methods decreases uncertainties.
    No preview · Article · Oct 2010 · Journal of Contaminant Hydrology
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    ABSTRACT: Monitored natural attenuation (MNA) as a possible remediation strategy has been intensively discussed over the last several years. However, in order to apply natural attenuation (NA) as a rational remediation option, suitable methods for the assessment and evaluation of the efficiency of these processes must be developed, the sustainability of the NA processes has to be demonstrated and regulatory and public acceptance has to be established. The RETZINA (Reference test site Zeitz for the implementation of the “Natural Attenuation” approach) -Project deals with the implementation of the MNA approach as a remediation concept at the heavily contaminated former industrial field site Zeitz (Germany). Due to the long history of industrial production, the multiple contaminant sources present and the large spatial extent, Zeitz is considered a contaminated megasite. The overall goal of the project is to incorporate novel site investigation methods into conventional strategies to improve site characterisation with respect to remediation measures relying on NA. Several investigation methods are being tested to examine temporal and spatial aspects of NA. In addition to conventional site investigation strategies, incorporation of new mass flux, toxicological and isotopic approaches form part of the research. Integral pumping tests yielded reliable data on mass fluxes through a control plane. The toxicological analysis gave new insights into contaminant interactions and the issue of multiple sources. Investigations of isotopic fractionation yielded increased confidence that NA is indeed ongoing at the site. Thus, the new methods gave more insight into the complexity of contaminant load and occurring degradation processes. Taken together, they strengthened the reliance on NA as a remediation option for this particular contamination at the megasite in context of the protection of water resources at the regional scale.
    Full-text · Article · Sep 2006 · Journal of Hydrology
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    ABSTRACT: Das Selbstreinigungsvermögen von Grundwasserleitern (NA) wird seit mehreren Jahren vor allem in den USA als kostengünstige Sanierungsmethode angewandt. Dabei werden die natürlichen Rückhalteund Abbauprozesse genutzt, um die Ausbreitung von Schadstoffen zu verlangsamen oder vollständig zum Stillstand zu bringen. Neben dem Vorhandensein von geeigneten Elektronenakzeptoren, Mikroorganismen und Nährstoffen sind die Redoxbedingungen im Grundwasserleiter von entscheidender Bedeutung für einen Schadstoffabbau. Die Untersuchung dieser Einflussfaktoren und deren Quantifizierung bildet den grundlegenden Schritt im Bezug auf die Einführung der „überwachten Selbstreinigung“ (Monitored Natural- Attenuation - MNA) des Aquifers als Sanierungsstrategie. Um neben der präzisen Bestimmung der Grundwasserfließrichtung, Verdünnung und Schadstoffabbau zu quantifizieren, sind Tracerversuche für die Anwendung von Natural-Attenuation Studien von großer Bedeutung.
    No preview · Article · Jan 2004