Multi-temporal Remote Sensing for Monitoring Hydro-Erosive Process Dynamics in Terraced Cultural Landscapes

Cultural landscapes embody the evolving relationship between humans and nature, often reflecting strong rural influences. Agricultural terraces are repositories of traditional knowledge, supporting the local economy through food production and economic development, including tourism. However, challenges such as field abandonment, inadequate maintenance, and extreme rainfall events significantly affect terrace systems. These issues lead to instabilities, wall collapses, landslides, floods, and debris flows, posing an imminent threat to their distinctive identity. The increased frequency of heavy rainfall due to climate change may exacerbate these problems. Therefore, monitoring hydro-erosive processes is crucial to mitigate these risks and protect the associated social and cultural values. Remote sensing technologies with High-Resolution Topography (HRT) surveys offer effective tools (e.g., multi-temporal Digital Elevation Models-DEM) for this purpose. This research introduces a preliminary workflow for monitoring instabilities in terraced cultural landscapes, focusing on Italy's UNESCO World Heritage site “Portovenere, Cinque Terre, and the islands”. The area is prone to such issues as evidenced by a dramatic flash-flood event in 2011. The method integrates data collected over different years and techniques (i.e., airborne laser scanning and photogrammetry), overcoming challenges associated with “old legacy” datasets. These data facilitated investigations of hydro-erosive processes over time, supporting hydrological modelling and geomorphometric indices to identify critical areas for rapid and targeted mitigation. Monitoring, planning, and preventive measures are crucial for enhancing resilience in terraced cultural landscapes, and remote sensing technologies are key in reshaping protective strategies and preserving these invaluable landscapes.