Integrated Low-Cost Approach for Measuring the State of Conservation of Agricultural Terraces in Tuscany, Italy

Abstract

Agricultural terraces are an important element of the Italian landscape. However, abandonment of agricultural areas and increase in the frequency of destructive rainfall events has made it mandatory to increase conservation efforts of terraces to reduce hydrological risks. This requires the development of new approaches capable of identifying and mapping failed or prone-to-fail terraces over large areas. The present work focuses on the development of a more cost-effective alternative, to help public administrators and private land owners to identify fragile areas that may be subject to failure due to the abandonment of terracing systems. We developed a simple field protocol to acquire quantitative measurements of the degree of damage—dry stone wall deformation—and establish a damage classification system. This new methodology is tested at two different sites in Tuscany, central Italy. The processing is based on existing DTMs derived from Airborne Laser Scanner (ALS) data and open source software. The main GIS modules adopted are flow accumulation and water discharge, processed with GRASS GIS. Results show that the damage degree and terrace wall deformation are correlated with flow accumulation even if other factors other than those analyzed can contribute to influence the instability of dry stone walls. These tools are useful for local land management and conservation efforts.

Keywords

• agricultural terraces
• maintenance
• failure risk
• LiDAR
• GRASS GIS
• land abandonment