Monitoring of torrent control structures: An integrated approach from first-level inspections to maintenance strategies

Torrent control structures are essential countermeasures against potential losses from flood to debris flow events. The durability of these structures hinges upon several factors, including the structure's design, construction materials and ongoing maintenance as well as the physical pressures they are under. Over the past half-century, a decline in investments allocated to routine maintenance activities, coupled with the natural degradation of these structures, has contributed to a reduction in their protective capacity. In this context, monitoring and maintaining existing structures are essential actions. This study presents a comprehensive proposal for a routine inspection process adopted for torrent control structures along four rivers in North Italy. The results of the first-level inspections consist of a dataset encompassing missing details (e.g., width, length, height, construction age, materials used), present condition of structures and functionality. The further step is to predict the vulnerability of the inspected torrent control structures; so, the Markov chain model is implemented for forecasting their service life, also in function of different maintenance strategies. Furthermore, this study serves as a valuable resource for reinforcing the role of the first-level inspections and ongoing monitoring, which is essential for planning future investments in watershed management, especially in the routine maintenance of torrent control structures.