Combined geophysical monitoring of a controlled LNAPL-Release

The exploration of contaminated sites represents a demanding task. Geophysical methods are predestined to deliver a high resolved spatial distribution of underground parameters. A promising strategy is to combine several geophysical methods. The development of qualified equipment and interpretation techniques should take place under undisturbed conditions. A large scale hydraulic experiment was carried out in February 1998 at VEGAS-facility (Versuchseinrichtung zur Grundwasser- und Altlastensanierung) at University of Stuttgart. One main part of the research doing there at VEGAS consists in the investigation of movement and spreading of non-aqueous phase liquids (NAPL' s) in the vadose zone. The objective was to monitor a hydraulic experiment using geophysical methods (complex conductivity tomography and cross-borehole radar tomography) and nongeophysical procedures (TDR, fluid level measurements, fluid pressure measurement).