Fig. 4. The volumetric water content as a function of time for selected segments of the TDR probes (a) TDR1 and (b) TDR2. The silty sand layer for TDR1 is situated at the depth of 190 to 212 cm, while for TDR2 it is situated at the depth of 237 to 250 cm. The time spans when bromide and hydrocarbons were applied are indicated on the figure.