Spatiotemporal meteorological drought assessment in a humid Mediterranean region: case study of the Oued Sebaou basin (northern central Algeria)

In this research, the spatiotemporal meteorological drought pattern was assessed in the Oued Sebaou basin (northern central Algeria) based on data from 23 rain gauges from 1972 to 2010 analyzed at seasonal and annual scales using the standardized precipitation index (SPI). A geographic information system was used to determine the cartographic precipitation concentration index and modified Fourier index (MFI) as well as the drought and rainfall characteristics of the stations. The analysis revealed moderate precipitation concentrations for all stations in the basin, for which longitude explains approximately 60% of the variance. The MFI results show three main aggressiveness distributions: weak, moderate and strong, which are similar to the spatial distribution of rainfall. The results show a prolonged drought that began in the late 1980s. In addition, more than 50% of the stations were affected by moderate and severe dry events during the period from 1986 to 2001. The comparison of the SPI values among the decades indicates that more than 20% of the cases were dominated by wet conditions from 1972 to 1981 and from 2002 to 2010, with near-normal and -normal events exceeding 70%. During the 2002–2010 decade, extreme wet events occurred in 7% of the cases, while in the 1972–1981 decade, only 1.75% of the cases were of this type. These results can provide watershed managers with more information to understand past drought and improve future water resource management.