title: Evaluation of combined direct-push methods used for aquifer model generation.
abstract: Most established methods to characterize aquifer structure and hydraulic conductivities of hydrostratigraphical units are not capable of delivering sufficient information in the spatial resolution that is desired for sophisticated numerical contaminant transport modeling and adapted remediation design. With hydraulic investigation methods based on the direct-push (DP) technology such as DP slug tests, DP injection logging, and the hydraulic profiling tool, it is possible to rapidly delineate hydrogeological structures and estimate their hydraulic conductivity in shallow unconsolidated aquifers without the need for wells. A combined application of these tools was used for the investigation of a contaminated German refinery site and for the setup of hydraulic aquifer models. The quality of DP investigation and the models was evaluated by comparisons of tracer transport simulations using these models and measured breakthroughs of two natural gradient tracer tests. Model scenarios considering the information of all tools together showed good reproduction of the measured breakthroughs, indicating the suitability of the approach and a minor impact of potential technical limitations. Using the DP slug tests alone yielded significantly higher deviations for the determined hydraulic conductivities compared to considering two or three of the tools. Realistic aquifer models developed on basis of such combined DP investigation approaches can help optimize remediation concepts or identify flow regimes for aquifers with a complex structure.
authors.affiliation: University of Kiel, Institute of Geosciences, Olshausenstrasse 40, D-24098 Kiel, Germany. rkoeber@gpi.uni-kiel.de
authors.forename: Ralf
authors.initials: R
authors.lastname: Köber
authors.forename: Götz
authors.initials: G
authors.lastname: Hornbruch
authors.forename: Carsten
authors.initials: C
authors.lastname: Leven
authors.forename: Lars
authors.initials: L
authors.lastname: Tischer
authors.forename: Jochen
authors.initials: J
authors.lastname: Grossmann
authors.forename: Peter
authors.initials: P
authors.lastname: Dietrich
authors.forename: Holger
authors.initials: H
authors.lastname: Weiss
authors.forename: Andreas
authors.initials: A
authors.lastname: Dahmke