|Reference Category||Qualification assignments|
|Title (Primary)||Critical evaluation of vertical high resolution methods for determining hydraulic conductivity|
|Keywords||Porosität; Hydrogeologie; Direct Push; Kf-Wert; Siebanalysen; Grain size analyses; Hydrogeology; Hydraulic conductivity; Porosity|
Environmental site investigations aim at delineating surface near (hydro-) stratigraphic units and their characterization. Knowledge about the spatial distribution of hydraulic conductivity (K) is the prerequisite for understand flow and fluid transport processes. Soil sampling and laboratory analysis of soil samples as well as the use of Direct Push (DP) technology are commonly applied methods for high resolution vertical characterization of sedimentary deposits.
The objective of this thesis is to provide a critical evaluation of these methods regarding their ability to reflect the structure of a complex sedimentary aquifer and their ability to predict K. Extensive field testing was conducted at different test site with focus of the field work at highly heterogeneous aquifer at the Bitterfeld test site.
Evaluation of methods to determine K from grain size analyses are based on the analyses of soil samples and multi level slug tests. Differences on calculated K between the different commonly applied formulas to calculate K were observed. Nevertheless, a high correlation was found between calculated and in situ measured K for most of the applied formulas. However, uncertainties that are associated with the (semi-) empirical nature of this method, heterogeneity of samples, and insufficient porosity estimates were identified to reduce the reliability of calculated K.
DP tools and sensor probes proved to be a reliable and efficient alternative for characterizing complex sedimentary systems in this thesis. Despite resolution differences, all of the applied methods captured the main aquifer structure. Results show that it is possible to describe the aquifer hydraulic structure on less than a meter scale by combining DP slug test data and continuous DP profiling data. However, the appropriate tool has to be chosen and parameter relations are site specific. Correlation between of high resolution DP profiling and grain size data on a centimeter scale was not possible due the small scale soil variability at the Bitterfeld test site.
|Persistent UFZ Identifier||https://www.ufz.de/index.php?en=20939&ufzPublicationIdentifier=11200|
|Vienken, T. (2011):
Critical evaluation of vertical high resolution methods for determining hydraulic conductivity
Dissertation, Universität Tübingen