Drought propagation in the hydrological cycle in a semiarid region: a case study in the Bilate catchment, Ethiopia

• Published in: Hydrogeology journal 2022-05, Vol.30 (3), p.751-766
• Main Authors: Wossenyeleh, Buruk Kitachew, Kasa, Ayalew Shura, Verbeiren, Boud, Huysmans, Marijke
• Format: Article
• Language: English
• Subjects: Analysis; Aquatic Pollution; Atmospheric models; Catchment area; Daily rainfall; Drought; Drought analysis; Earth and Environmental Science; Earth Sciences; Geology; Geophysics/Geodesy; Groundwater; Groundwater recharge; Hydrogeology; Hydrologic cycle; Hydrologic drought; Hydrological cycle; Hydrology; Hydrology/Water Resources; Propagation; Rain; Rainfall; Rainfall measurement; Rift valleys; River catchments; Semi arid areas; Semiarid lands; Semiarid zones; Standardized precipitation index; Temporal resolution; Waste Water Technology; Water availability; Water balance; Water Management; Water Pollution Control; Water Quality/Water Pollution; Weather stations
• ISSN: 1431-2174; 1435-0157
• DOI: 10.1007/s10040-022-02459-8

Drought is a temporal decrease in water availability and occurs in all climatic regions. Droughts propagate through the hydrological cycle, e.g., meteorological drought propagates to groundwater recharge drought. This research investigated drought propagation in the hydrological cycle in a semiarid context. Meteorological drought severity was determined using a standardized precipitation index (SPI). A variable threshold method and standardized groundwater index (SGI) was implemented to investigate groundwater recharge drought. Comparing meteorological drought (SPI) and groundwater drought (SGI) helps to assess drought propagation in the hydrological cycle. For drought analysis, time-series of rainfall and groundwater recharge needs to be available with high spatial and temporal resolution. Therefore, for this study, daily rainfall measurements were collected from 11 meteorological stations, and water balance modeling was used to estimate temporally and spatially distributed groundwater recharge. This research was carried out in the Bilate River catchment in the Rift Valley basin of Ethiopia. Results show that meteorological droughts were observed before every groundwater recharge drought and they propagate to groundwater recharge drought. Furthermore, analysis of the drought propagation indicates that not all meteorological droughts are propagated. The analysis also shows that a combination of mild to severe meteorological droughts can propagate to groundwater recharge and result in a major groundwater-recharge drought event.