water Article Integrated Low-Cost Approach for Measuring the State of Conservation of Agricultural Terraces in Tuscany, Italy Martina Cambi 1 , Yamuna Giambastiani 2,3,4,5, *, Francesca Giannetti 1,3,5, * , Elena Nuti 1 , Andrea Dani 1 and Federico Preti 1,5   Citation: Cambi, M.; Giambastiani, Y.; Giannetti, F.; Nuti, E.; Dani, A.; Preti, F. Integrated Low-Cost Approach for Measuring the State of Conservation of Agricultural Terraces in Tuscany, Italy. Water 2021, 13, 113. https://doi.org/10.3390/w13020113 Received: 18 November 2020 Accepted: 29 December 2020 Published: 6 January 2021 Publisher’s Note: MDPI stays neu- tral with regard to jurisdictional clai- ms in published maps and institutio- nal affiliations. Copyright: © 2021 by the authors. Li- censee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and con- ditions of the Creative Commons At- tribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/). 1 Dipartimento di Scienze e Tecnologie Agrarie, Alimentari Ambientali e Forestali, Università degli Studi di Firenze, 50121 Firenze, Italy; cambimartina85@gmail.com (M.C.); elena.nuti1988@gmail.com (E.N.); studio.daniandrea@gmail.com (A.D.); federico.preti@unifi.it (F.P.) 2 CNR-IBE—Consiglio Nazionale della Ricerca, Istituto di BioEconomia, 50019 Florence, Italy 3 Bluebiloba Startup Innovativa SRL, 50126 Florence, Italy 4 LaMMA Consortium, 50019 Florence, Italy 5 Laboratorio Congiunto ForTech, 50145 Florence, Italy * Correspondence: giambastiani@lamma.toscana.it (Y.G.); francesca.giannetti@unifi.it (F.G.); info@bluebiloba.com (Y.G. & F.G.) Abstract: Agricultural terraces are an important element of the Italian landscape. However, aban- donment 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; flow accumulation; water discharge 1. Introduction The difficult morphology of mountainous and hilly areas often hindered land cultiva- tion and forced local communities to re-shape the land in a way that would facilitate its agricultural use [1,2]. Historically, the creation of terraces has been considered the most efficient way to allow agriculture and forestry in mountainous and hilly regions all over the world [3,4]. Terraces have allowed for the cultivation of a wider variety of crops, thereby increasing not only the productive areas, but also the quality of landscapes [2,3,5]. As a result, terraces are now a ubiquitous feature in many mountainous regions all over the world [3,5–10] and have been recognized as a distinct element of a region’s cultural identity and heritage because they form important landscape elements and characterize a territory due to their particular design [3,5,11,12]. Even within the same country and if the intent was to cultivate the same crop, it is often possible to find terraces that are designed in very different manners, e.g., different height, using different types and sizes of stones, and with different arrangements for water regulation [1,3,13–15]. In Tuscany, the terraced vineyards Water 2021, 13, 113. https://doi.org/10.3390/w13020113 https://www.mdpi.com/journal/water