Geoinformatics and analytic hierarchy process based drought vulnerability assessment over a dryland ecosystem of north-western India

Drought vulnerability is the extent to which an area is susceptible to damage as well as causing a threat to human society. Drought frequently occurs in the Indian state of Rajasthan, and so far, very little attention has been paid towards its vulnerability assessment. Therefore, the present study focuses on a spatial multi-criteria integrated technique for an all-out drought vulnerability assessment and mapping consisting of geographic information systems (GIS) and analytic hierarchy process (AHP) techniques. The data have been acquired from various secondary sources pertaining to a total of 16 indicators under meteorological (rainfall, temperature and evapotranspiration), hydrological (hydrogeology, elevation, groundwater level, groundwater development and surface water bodies), agricultural (available water holding capacity of soils, land use and slope) and socio-economic (density of population, female-to-male ratio, irrigated land, agriculture-dependent population and deep tube wells) drought categories. Further, spatial layers for each category have been developed by various GIS operations followed by the calculation of weights for each drought category and type employing pair-wise comparison matrices by means of AHP criterion. Afterwards, individual drought category and comprehensive drought vulnerability maps have been prepared by employing the weighted overlay technique. The generated maps have effectively displayed the areal spreads and levels of drought vulnerability with respect to normal, mild, moderate, severe and extreme category of droughts. The findings from this study have demonstrated a proneness of severe to extreme drought vulnerability in 25% area of the state. Distinctively, the eastern, western, central and small pockets of south-western parts of the state have witnessed severe to extreme drought vulnerability, while the remaining areas have demonstrated normal to moderate drought vulnerability. The results of the overall drought vulnerability have been validated by employing normalized difference vegetation index and past occurrence of drought disasters, which revealed an accuracy of 81%. The obtained results prove the effectiveness of geoinformatics and AHP techniques in comprehensive drought vulnerability assessment and mapping. Finally, the findings of the present study may be easily applied for designing suitable drought mitigation strategies of the vulnerable areas.