Spatiotemporal analysis of meteorological drought in a Mediterranean dry land: case of the Cheliff basin–Algeria

Abstract

Drought is amongst the most significant natural hazards threatening human societies and ecosystems. The present study concerns monitoring the spatiotemporal evolution of meteorological drought in the Cheliff Basin northwestern Algeria based on available rainfall data that covers a period of 73 years from 1936 to 2008. The procedure employed herein involved analyzing the homogeneity of rainfall series along with the calculation of the standardized precipitation index (SPI). Results of homogeneity analysis revealed important inter-annual variability and a generalized decreasing trend of annual rainfall amounts accompanied by shifts of stationarity observed between 1974 and 1980. The analysis of the temporal evolution of the SPI revealed significant changes in the characteristics of drought events, arguably after 1976 the observed drought events were characterized by significantly higher intensities, durations and frequencies. The spatial distribution maps of mean SPI before and after 1976 generated in a geographic information system (GIS), enhanced the appreciation of the significant changes of drought conditions during the studied period and, more important, emphasized the strong spatial component of the recent drought events. The results of this study may help decision-makers of the local authorities in planning and managing water resources over the Cheliff basin.