Georadar as a tool to identify and characterise solid waste dump deposits

This paper reports the ability of a ground-penetrating radar survey to dete ct and characterise uncontrolled waste dumps. The dumps in our study are lo cated just outside Rome, date back to the 1960s, and have long been abandon ed. It is probable that stored there are heterogeneous refuse, i.e. househo ld refuse, building rubble and/or industrial refuse. The Ponte Malnome dump overlies Quaternary alluvial sediments and the Regione Lazio dump, located in an abandoned quarry of gravel and coarse-sand extraction, lies on Plio- Quaternary fine sediments. The sites were surveyed with georadar equipped w ith 50-, 100- and 200-MHz antennas. The results of the first site were comp ared and integrated with VES, multielectrode and boreholes and the second w ith VES and seismic refraction results obtained prior to the present study by Cardarelli et al. (1997). The study confirmed that georadar can be used to detect such dumps and define the geometry of the waste dump body. On the georadar records, the in situ sediments are stratified while the dump depo sits produce diffraction and noncontinuous reflections. In the Ponte Malnom e site, the georadar allowed us to define the actual eastern limit of the w aste dump deposits, finding it wider than was presumed from geological surv ey, and define the type of refuse-mainly building rubble. The geophysical r esults were confirmed by boreholes. In the Regione Lazio, the georadar allo wed us to define the limits of the waste dump and to discriminate between s urficial household refuse and underlying quarrying waste. The study demonst rates that even in unfavourable conditions, georadar can provide useful inf ormation for locating and characterising abandoned urban dumps. (C) 2001 El sevier Science B.V. All rights reserved.