Shifting of Meteorological to Hydrological Drought Risk at Regional Scale

TLDR

Drought and climate variation pose serious challenges to human society and ecosystems in the arid Soan basin, with discrepancies arising from differing onset/termination times and anthropogenic activities. The study aims to conduct spatiotemporal analysis of drought types to assess their linkage for early warning. The authors used the streamflow drought index (SDI) and standard precipitation index (SPI) along with regression, Mann–Kendall trend analysis, and moving‑average methods to examine the linkage, significance, and lag between hydrological and meteorological droughts. The analysis revealed increasing frequencies of both hydrological and meteorological droughts over the past three decades, a strong but spatiotemporally varying linkage between them, and significant differences, underscoring the study’s relevance for basin‑scale water resource management.

Abstract

The drought along with climate variation has become a serious issue for human society and the ecosystem in the arid region like the Soan basin (the main source of water resources for the capital of Pakistan and the Pothohar arid region). The increasing concerns about drought in the study area have brought about the necessity of spatiotemporal analysis and assessment of the linkage between different drought types for an early warning system. Hence, the streamflow drought index (SDI) and standard precipitation index (SPI) were used for the analysis of the spatiotemporal variations in hydrological and meteorological drought, respectively. Furthermore, statistical approaches, including regression analysis, trend analysis using Mann Kendall, and moving average, have been used for investigation of the linkage between these drought types, the significance of the variations, and lag time identification, respectively. The overall analysis indicated an increase in the frequency of both hydrological and meteorological droughts during the last three decades. Moreover, a strong linkage between hydrological and meteorological droughts was found; and this relationship varied on the spatiotemporal scale. Significant variations between hydrological and meteorological droughts also resulted during the past three (3) decades. These discrepancies would be because of different onset and termination times and specific anthropogenic activities in the selected basin for the minimization of hydrological drought. Conclusively, the present study contributes to comprehending the linkage between hydrological and meteorological droughts and, thus, could have a practical use for local water resource management practices at the basin scale.