Drought characterization using different indices, theory of run and trend analysis in bilate river watershed, rift valley of Ethiopia

Droughts have become more powerful and frequent, affecting people for longer periods than any other natural disaster, particularly in eastern Africa. The unprecedented climate change has increased the severity, duration, frequency of droughts. objectives this study were to evaluate performances different drought indices spatiotemporal characterization Bilate river watershed that represents part rift valley drylands Ethiopia. Historical data 39 years (1981–2019) from seven stations used analyses using following indices: Standardized Precipitation Index (SPI), Evapotranspiration (SPEI), Reconnaissance Drought (RDI), enhanced (eRDI) with time scale Self-Calibrated Palmer Severity (scPDSI). Among them, SPI, SPEI, RDI eRDI 6-month 9-month scales found be best correlated characterize historical events. Then, selected indices, temporal analysis showed occurrence major events years: 1984/85, 1999/2000, 2002/3, 2009. Some these are well known as famine some parts Ethiopia including area. results revealed spatial variation severity extreme droughts occurred southern watershed. Application theory run confirmed maximum duration observed at Tena station is located watershed; most severe being on a during 1984/85. Hossana Wulbareg highest over period. Mann-Kendal trend test statistics an increasing conditions