Long-Term ERT Monitoring of Parma River Levee in Colorno, Italy

Electrical resistivity tomography (ERT) method was suggested to monitor a critical section of the Parma river levee in Colorno, Italy. The site had experienced a leakage in 2017 and the damaged zone was repaired with a clay-rich material that was different from the existing old parts of the levee. The customized monitoring system supports 48 electrodes that are spaced 2m and buried at 0.5m depth. Meteorological sensors were also integrated with the ERT system to monitor rainfall and temperature variations. We discuss the most important data processing steps and long-term analysis of the ERT monitoring data for a two-year period. Raw data were processed before inversion to remove the 3D effects related to the specific geometry of the levee. Inverted data were then corrected for seasonal temperature variations. Observing average resistivity trends, a reasonable response to rainfalls is observed inside the embankment with no indication of any anomalous behavior that could compromise the levee's stability.