Integration of low-cost technological solutions for flow rate and bedload transport monitoring in the Caldone river, Italy

Development of technology in the digital age produces an echo in every corner of science and engineering. River monitoring has always been a challenging task, but the emergence of a variety of technological solutions allows for the acquisition of new data which broadens our understanding of processes related to water and sediment fluxes and their further implications for river basin management, hydraulic engineering, land use planning, and flood risk analysis. In this manuscript we present the results obtained from a set of innovative monitoring techniques used for the description of sediment transport in a pre-Alpine river located in Northern Italy. Largescale particle image velocimetry was used for river discharge estimation, to be later complemented by an Arduino-based automatic gauge station. Furthermore, bedload transport has been monitored through tracking of RFID-equipped pebbles at a designated river reach; the filling of a sedimentation basin has been followed through bathymetric surveys using a DIY aquatic drone armed with a portable fishing sonar sensor; threshold sediment size for entrainment has been assessed by image analysis of pictures taken before and after an event. All the proposed tools are characterized by a limited cost and are fairly easy to operate, while their application aims to enhance sediment transport monitoring. The integration of those tools could ultimately render an exhaustive picture of the river dynamics.