Terraced Landscapes and Hydrological-Geological Hazards: Innovative Approaches and Future Perspectives

In the last few years, terraced landscapes have been receiving renovated interest all over the world (e.g., dry-stone walls named UNESCO heritage in November 2018). Terracing was recognized as a fundamental component of agricultural systems, both for its cultural value as well as for its importance in guaranteeing food production in unfavorable environments. Such landscapes are among the most evident fingerprints of humankind on terrestrial ecosystems [1], aiming at generating new surfaces available for cultivation in sloping areas, reducing runoff and soil erosion, harvesting and storing rainwater, accumulating biomass by increasing crop production, and restoring ecosystems themselves [2]. The scientific community has been investigating the environmental effects related to terracing for many decades, and, within this framework, hydrological and hydrogeological processes occurring in terraced landscapes. Latest studies showed that terracing represents a radical alteration of pre-existing terrain morphology, thus altering water infiltration and runoff generation processes, and ultimately influencing the entire water cycle from the single terrace up to the slope, catchment, and landscape scales [3,4]. Sound terracing implementation and terraced landscape restoration can contribute to reduce hydrological and hydrogeological hazards, as well as soil erosion and land sliding [5]. On the one hand, this latter effect can be relevant both at the local scale, reducing hazards to agricultural areas, and at the catchment scale, reducing hazards to population and infrastructures located downstream. On the other hand, deteriorated terraced systems, as well as poorly managed or designed terraces, may increase these hazards, and even enhance the triggering of degradation phenomena [6,7]. Recent developments in scientific and technological research techniques have offered the possibility of increasing knowledge of the terracing–hydrogeological hazard nexus, including, for instance, advanced and detailed geomorphological analysis [8,9], and hydraulic, geotechnical, and hydrological modeling [4,10,11,12]. Given these premises, the aim of the present Special Issue was to gather studies dealing with hydrological–geological risk mitigation given by terraced landscapes, with the potential hazards induced by degraded and/or abandoned terracing, and with effective terrace management strategies. The submission of works showcasing innovative methodologies for the analysis of terraced landscapes and papers on newly implemented terraced systems was encouraged, with a preferred focus on African, South East-Asian, and Latin American countries.