Drought vulnerability assessment and mapping using Multi-Criteria decision making (MCDM) and application of Analytic Hierarchy process (AHP) for watershed area of Lake Bolsena of Central Italy

Abstract

Draught is one of the major climate related disaster that Italy has been fighting in the recent years .It is a complex multidimensional phenomenon that is dependent upon on a wide variety of parameters ranging from climatic to socioeconomic ones. In this study we are considering watershed area of lake Bolsena, which is one of the most important water resources in central Italy, to asses in drought vulnerability using Geographical Information System (GIS)  in combination with the Analytic Hierarchy Process (AHP). GIS is used for the spatial analysis of drought for Lake Bolsena watershed area for the year 2022 which was one of the worst draught affected year in the history for the country. Parameters such as Monthly rainfall, Land use/Landcover (LULC), elevation , soil type, Normalized difference vegetation index (NDVI), Normalized Difference turbidity Index (NDTI),Normalized differentiate chlorophyl index(NDCI), Normalized Difference Water Index (NDWI),Storm power index (SPI)  were chosen and considered for the study. AHP is used to calculate weightage factors of each criterion based on the pairwise comparison matrices. The thematic maps of all the parameters were analyzed and Drought Vulnerability Assessment (DVA) map was generated using GIS. The output DVA map will provide valuable information on drought severity in the area and vulnerability related to water availability.