Installation and validation of a customized resistivity system for permanent monitoring of a river embankment

Development of early warning alarm systems for hydrogeological risk assessment is seriously under research in different European countries. In this paper, we discuss the installation and validation of a prototype electrical resistivity tomography (ERT) system for permanent monitoring of river levees. ERT measurements were performed on various candidate sections of river embankments in Lombardy and Emilia-Romagna regions in Italy for preliminary evaluation of critical sites to be monitored. Based on careful analysis of all datasets, a critical part along an earthen embankment of the Parma river in Colorno was selected to be permanently monitored. A customized ERT monitoring system using the Wenner array with 48 stainless steel plate electrodes was installed in November 2018. The system is making two measurements every day, sending the datasets to a Cloud platform through the mobile-phone network. Time-lapse analysis of datasets measured by the prototype and control measurements with commercial equipment show that the installed system is operating well. The research is in progress to define the thresholds of instability based on water saturation maps calculated from resistivity sections.