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Application of the LDN concept for quantification of the impact of land use and land cover changes on Mediterranean watersheds - Al Awali basin - Lebanon as a case study

Al Sayah, Mario J., Abdallah, Chadi, Khouri, Michel, Nedjai, Rachid, Darwich, Talal
Catena 2019 v.176 pp. 264-278
USDA, United Nations, anthropogenic activities, basins, case studies, desertification, inventories, land classification, land degradation, land use and land cover maps, neutralization, planning, remote sensing, runoff, soil conservation, soil types, sustainable development, watersheds, Lebanon, Mediterranean region
Recognized by the United Nations Convention to Combat Desertification (UNCCD) as a global developmental and environmentally threatening process, land degradation (LD) is initiated by natural factors but aggravated by unsustainable anthropogenic activities and absence of proper management plans. Therefore, in response to the UN 2030 Agenda on Sustainable Development for restoring degraded lands, this research targets the impact of land use and land cover changes (LU/LC), under the UNCCD's Land Degradation Neutrality (LDN) concept, to identify the extent of LD, and to prospect the potential to counterbalance/neutralize ongoing degradation as a first approach to Lebanon, at the scale of the 301 Km2 Awali basin. By achieving this task, the proposed method will serve as a first step in building an inventory of LD and proposing measures to adapt or even overcome LD for applications in the Mediterranean basin's countries.The proposed sequential methodological approach consists of tracking detailed LU/LC changes from 1998 to 2016 using multitemporal satellite images. Generated maps are input to the Soil Conservation Service SCS-Curve Number (CN) method to determine surface runoff in complementarity to Pedological properties of the study area. Soil types are then classified under the USDA Land Capability Classification method to determine extent of degraded lands. Results intersected with LU/LC revealed the source and nature of mismanagement and the proposed counterbalancing steps.Two main findings result: the Awali watershed displays countable LU/LC changes translated in CN increases. Additionally, due to these changes, the basin displays a 36% LD that may continue to alarming rates if no intervention takes place. The proposed workflow combining existing methodologies enabled the application of the LDN concept to counterbalance losses by gains thus reducing degradation to 2% from alternative land planning, and near null from proposed soil corrective actions highlighting the importance of LDN usage.