Spatiotemporal characteristics and driving factors of groundwater drought in Nile River Basin (NRB)

Abstract

Understanding groundwater drought characteristics and the driving factors is vital for sustainable groundwater management. Using Nile River Basin (NRB) as a testbed, this research examines spatial patterns, temporal changes, and overall trends of groundwater droughts using standardized groundwater drought index (SGDI) model in areas with distinct climate conditions. The study quantitatively assesses the influence of anthropogenic (LULC), meteorological, and teleconnection factors using correlation analysis, cross-wavelet transform, and Random Forest (RF) methods. Based on this study, groundwater droughts predominantly occurred between 2003 and 2013 with a general decreasing trend, and the occurrence of groundwater droughts was closely aligned with meteorological drought, with a propagation time of at least three months. Precipitation positively contributed to mitigating groundwater droughts across the study area but was insufficient to reverse drought intensification. Teleconnection factors significantly influenced the development of groundwater droughts, with DMI and ENSO identified as key contributors. Changes in LULC, such as a decrease in barren land, cropland, and grassland, along with an increase in vegetation and water bodies, played a key role in alleviating groundwater droughts in NRB. Conversely, the expansion of urban areas did not seem to worsen drought conditions. Quantitative analysis highlights LULC and meteorological factors as the primary drivers of groundwater droughts, though the influence of teleconnection factors, while weaker, remains important. Overall, this study highlights factors influencing groundwater droughts, supporting decision-making for sustainable groundwater management in diverse climates.