Innovative and traditional monitoring system for characterizing the seepage inside river embankments along the Adige River in Salorno (Italy)

Despite the great development of geotechnical and hydraulic engineering in the last years, still the levee collapses induced by seepage are periodically occurring events. Therefore, increasing knowledge on existing embankment structures through investigation and monitoring activities, is fundamental for evaluating their safety condition. Nevertheless, this monitoring is complex due to their considerable linear extension and the high spatial soil variability affecting both the levee body and the foundation, especially for the presence of paleo river networks. Recently, both traditional survey and innovative field monitoring techniques have greatly improved. For instance, the use of distributed optical fiber sensors to measure the temperature variations is considered very attractive by researchers and land managers because they allow high-spatial resolution distributed measures over large areas. This paper deals with the monitoring of an Adige River embankment carried out in Salorno (BZ) in 2021. Here, a test field was installed to characterize the seepage within the foundation soils as detailed as possible. Five boreholes were realized at the corners and center of a square area, 20 m of lateral side, positioned straddles on the embankment structure. Each borehole hosts three different monitoring equipment: optic fiber cables for detecting the temperature variations along the well, electrical cables for 3D ERT measurements, two piezometric cells, and two thermal probes. In addition, many undisturbed samples were collected for a comprehensive characterization of the soils through laboratory tests. The monitoring data collected in the field will be used for better understanding the hydraulic behaviour and the safety condition of the levees in this section, but also for fully assessing the potential and reliability of these novel monitoring techniques.