Integrated decisional approach for watershed vulnerability prioritization using water and soil hazard index (WSHI) and AHP methods: Chiba watershed, Cap-Bon region, northeast Tunisia

The present work has been conducted to comprehend multi-influencing parameters on water and soil degradation in watershed to undertake the diminution of the drought impact on farming areas caused by the proclaimed climate change. The current work involves the employment of the analytical hierarchy process (AHP) method as a decisional multi-influencing parameter approach for watershed vulnerability prioritization areas in order to ensure water and soil conservation based on various water and soil hazard conservation parameters. To perform the prioritization of the vulnerable zones, the Chiba watershed which is part of Cap-Bon region in the governorate of Nabeul, northestern Tunisia, has been chosen and subdivided into sixteen subwatersheds. To handle with the decisional approach for watershed vulnerability prioritization, the initial dataset comprises six basic parameters such as rainfall, soil texture, slop class, land use/land cover, drainage density, and lithology. Water and soil hazard index (WSHI) model was established based on five thematic layers, namely soil erosion (SE), deposit rate (DR), deposit erosion index (DEI), runoff capacity (RC), and land adaptation capacity (LAC). Results show that 8 subwatersheds are the most vulnerable where 4 subwatersheds (CH5, CH3, CH1, and CH2) are falling under very high priority zone and 4 subwatersheds (CH15, CH8, CH9, and CH6) under high priority. Accordingly, water and soil conservation actions in these zones should be executed quickly according to various specific techniques to protect the farming areas and ensure a sustainable development of these rural zones. The proposed method can be employed effectively in prioritization of water and soil conservation measures and can help decision makers in the establishment of development plan of catchment area.