Spatio-temporal assessment of hydro-climatic trends in the Upper Baro River Basin, Ethiopia

Abstract

Understanding hydroclimatic variability is essential for sustainable water resource management. This study assesses hydro-climatic trends and spatio-temporal variability across the Upper Baro River Basin, Ethiopia (23,322 km 2 ). It uses historical records from 10 rainfall and 6 temperature stations from the Ethiopian Meteorological Institute, alongside 3 streamflow stations from the Ministry of Water and Energy. Variability was evaluated using the Coefficient of Variation and Standardized Anomaly Index; trends were analyzed using Mann–Kendall, Modified Mann–Kendall (MK-TFPW), Sen’s slope, Innovative Trend Analysis, and Linear Regression. Rainfall exhibited strong spatial variability: higher in southern highlands and lower in western lowlands. Annual rainfall variability was low, but winter (bega) varied highly (36–69%). Significant increasing annual rainfall trends occurred at Alem Teferi (12 mm/year, p < 0.01) and Yubdo. Maximum temperatures rose significantly at Gore (0.025 °C/year, p < 0.005) and Dembidolo ( p  < 0.05), while minimum temperature showed a non-significant annual trend and mixed seasonal trends. Streamflow exhibited high winter variability and a significant summer (kiremt) decline at Baro Gambella (− 7.4 m 3 /s, p < 0.05). This decline could be driven by reduced summer rainfall and rising temperatures, combined with documented forest loss and agricultural expansion. Overall, the basin exhibits increasing hydroclimatic variability, warming temperatures, uneven rainfall distribution, and declining summer streamflow. These trends threaten local farming livelihoods and ecosystem health by creating severe water shortages. This study provides the essential local evidence needed to build targeted watershed plans that protect shared water resources (SDG 6) and build resilience against climate shocks (SDG 13).