MAPPING OF NON-AQUEOUS PHASE LIQUIDS USING TIME DOMAIN REFLECTOMETRY / Kartering av icke vattenlösliga vätskor med tidsdomän reflektometri
A two-dimensional multi-fluid flow experiment was performed in a container (45 cm x 54 cm x 20 cm) filled with fine sandy soil. A dye stained light nonaqueous phase liquid (LNAPL) was applied in four releases over a rectangular area of 5 x 20 cm at the center of the soil surface. The releases varied in the way of the application; constant rate, constant head, and variable head. 42 Time Domain Reflectometry probes (TDR) was used to detect the transport and the location of the LNAPL and water with time. In addition to the TDR measurements images about the LNPAL migration were taken using a digital camera. Significant changes in the responses of TDR were observed. Based on the information from the mapping of the LNAPLs using digital pictures and fluid mass balance calculations, it was shown that the TDR system can provide accurate information on location, distribution, and quantity of LNAPLs in the unsaturated zone in a multi-fluid system. It was possible to reach an estimation of the water content with an error less than 0.01 m3 m-3 and the NAPL content with an error less than 0.045 m3 m-3.