Innovative Methods for Mapping the Suitability of Nature-Based Solutions for Landslide Risk Reduction

The impacts of climate change are becoming more widespread across the world, with hydro-meteorological extreme events on the rise, causing severe threats to nature and communities. Increasing trends in the frequency and intensity of floods and landslides have been projected by climate models. This necessitates the development of more effective measures such as nature-based solutions (NBS) which can complement grey infrastructures. Recent studies have identified knowledge gaps and limitations in existing research and tools that aid in spatial planning for the implementation of large-scale NBS and proposed new methodologies for the spatial allocation of large-scale NBS for flood risk reduction. This work presents a novel method for mapping the suitability of NBS addressing geo-hydrological hazards such as shallow landslides, debris flow, and rockfall, which are typically caused due to slope instability. This methodology incorporates landslide susceptibility mapping, and was used to create a toolbox ESRI ArcGIS environment to aid decision-makers in the planning and implementation of large-scale NBS. The spatial allocation toolbox was applied to the case study Portofino promontory, Liguria region, Italy, and 70% of the area was found to be highly susceptible to landslides. The produced suitability maps show that 41%, 33%, and 65% of the study area is suitable for the restoration of terraces, bio-engineering, and vegetative measures such as NBS for landslide risk reduction.

Automated summary

Climate change is causing increasingly widespread impacts, with more frequent and intense hydro-meteorological extreme events posing severe threats to nature and communities. To address these risks, the development of nature-based solutions (NBS) alongside traditional infrastructure is necessary. However, existing research and tools for spatial planning of large-scale NBS have limitations, thus this study proposes a novel methodology for mapping the suitability of NBS to address geo-hydrological hazards. By incorporating landslide susceptibility mapping, a toolbox was created using ESRI ArcGIS to assist decision-makers in planning and implementing large-scale NBS. Applied to a case study in Italy's Liguria region, the toolbox identified areas highly susceptible to landslides and determined the suitability of different NBS measures for reducing landslide risk.