Detection and analysis of LNAPL contaminated site by integrated time-lapse GPR surveys

Based on time-laspe ground penetrating radar(GPR)surveys and radar signal attributes analysis, we observed clear waveform, instantaneous phase and reflectivity changes caused by the contaminated soil and underground water table fluctuation. Time dependent radar response changes appeared to be consistent with continuous water table depth measurements that in phase with the known length of a day tidal changes. The observations are further confirmed from indoor analyses including ERI, ation. We have established a reliable standard operation procedure, in-door verification protocol, GIS related data base system and close to realtime field screening technique for investigating LNAPL contaminated site. The GPR responses and associated evidences clearly indicate that the site is affected by the migration of contaminated hydrocarbons. GPR application approved to be sensitive for high contaminated soil rather than dissolved phase or slightly contaminated soil.