Monitoring landfill cover by electrical resistivity tomography on an experimental site

In France, the monitoring of landfill cover after closure of the site is a local problem, since its tightness must be ensured over time. Leaks in the cover are a problem, as they allow water to infiltrate the stored waste. In order to locate such leaks, electrical resistivity tomography was used on an experimental site in which defects had been intentionally made in the cover. Repeated measurements taken on this site showed that the weather conditions preceding the measurements need to be taken into account, as they affect the water content in the cover material. They also showed that there are optimal weather conditions for detecting defects in the cover. A statistical analysis carried out on the electrical resistivity results for all surveys and cover material samples showed that the material was heterogeneous; this variability was mainly due to a difference in particle size (fines content) and in compaction.This study has shown the capacity of electrical resistivity tomography to detect defects and heterogeneity in the cover material, indicating that it is a good means of monitoring the quality of landfill cover both when it is put in place and subsequently.

► Defects in landfill cover need to be detected. ► We monitored a clayey cover by means of electrical resistivity tomography. ► Variations of electrical resistivity had been related to the cover's heterogeneity. ► Its heterogeneity was due to a difference in particle size and compaction. ► The cover's characterization was easier during wet periods.