Remote Sensing for Monitoring Macroplastics in Rivers: The Case of The Sarno River, Italy

Given the exponential rise in global plastic production and its significant ecological and socio-economic impacts, monitoring macroplastics in rivers has become a central focus of water management efforts. However, standardized monitoring methodologies have not kept pace with the increasing volume of plastic waste entering aquatic systems worldwide. This resulted in a critical shortage of spatially and temporally refined data on macroplastic pollution circulating in inland waters. Recent advancements in remote sensing technologies such as satellites, unmanned aerial systems (UASs) and camera systems coupled with crowd-sourced data and automated detection using machine and deep learning, offer promising opportunities for versatile monitoring solutions. Towards improving monitoring practices, we reviewed emerging remote sensing methods and tools to tackle macroplastic identification in riverine environments. Our investigation highlights that overcoming the challenges of remote sensing-based river macroplastics monitoring requires further efforts to integrate multiple platforms and prioritize long-term monitoring strategies. The RiverWatch project exemplifies these advancements by developing an innovative infrastructure for detecting buoyant plastics in rivers. Utilizing fixed cameras along river networks and mobile cameras, including those operated by citizens via smartphones, RiverWatch employs advanced computer vision algorithms to analyse collected data. Focused on the Sarno River, among the most polluted rivers in Italy, this project harnesses low-cost, adaptable technologies and empowers citizen science through the RiverWatch mobile app, enhancing both spatial and temporal monitoring resolution. The project aligns with the broader goals of offering scalable and harmonized monitoring solutions. Furthermore, it serves as an example of integrating emerging technologies into standardized methodologies, bridging the gap between research advancements and practical applications for global riverine systems.