On January 24,2025, Simir Birihan, a PhD candidate at the African Center of Excellence for Water Management (ACEWM), has successfully defended his dissertation, entitled “Modeling the Spatial Patterns of Runoff-Generating Areas and Soil Erosion in the Dirima Watershed, Upper Blue Nile, Ethiopia.” This milestone represents a vital contribution to the understanding of environmental dynamics in one of Ethiopia’s crucial watersheds; an area significantly affected by soil erosion and water management challenges.

Under the guidance of his supervisors, Dr. Simir employed advanced modeling techniques to analyze the spatial patterns of runoff and soil erosion, generating insights that could help mitigate these critical issues within the Dirima Watershed.

Dr. Simir’s study focuses on the Dirima watershed (162 km²) in the upper Tana Basin, modeling runoff-generating areas (RGAs) and soil erosion using SWAT+ integrated with the Analytic Hierarchy Process. In his study, Calibration (1996–2005) and validation (2006–2009) yielded NSE and R² values of 0.7 and 0.9, respectively. The watershed was classified into five RGAs, with very high areas generating 690.2 mm runoff and 186.5 t/ha/year sediment yield. Surface processes accounted for 53% of the water balance (671.6 mm), while soil and groundwater contributed 20.9% (280.86 mm) and 20.2% (251.23 mm).

According to Dr. Simir, Best Management Practices (BMPs) reduced runoff and sediment yield significantly: terraces by 25.46% and 57.32%, vegetative strips by 24.58% and 31.92%, and grass waterways by 16.97% and 38.21%. Combined BMPs achieved up to 33.95% runoff and 76.42% sediment yield reduction, promoting sustainable watershed management.

The defense session was chaired by Dr. Beteley Tekola of Addis Ababa University. Dr. Samuel Dagalo from Arba Minch University and Dr. Dessie Nedaw from Addis Ababa University, were external and internal examiners respectively. Prof. Tenalem Ayenew from Addis Ababa University was the main supervisor of this dissertation where as Dr. Fasikaw Atanaw from Bahir Dar University was co-supervisor.

The successful defense of this dissertation not only marks a personal achievement for Dr. Simir Birihan but also reflects the growing emphasis on environmental research within Ethiopian academia. As the nation faces numerous ecological challenges, scholars like him play a crucial role in advancing knowledge and informing policy to protect and manage natural resources for future generations.

The ACEWM community extends its congratulations to Dr. Simir Birihan on this remarkable accomplishment and looks forward to his future contributions to the field of environmental science and management.