Management Implication of Understanding Flood Variabilities in Transboundary Rivers for Future: A Case of Wabi Shebele River Basin, Ethiopia

Abstract

Floods are among the most severe hydrological extremes, in terms of social impact and potential economic damage. In this study, flood variability and associated impacts and managements are investigated in the Wabi Shebele River Basin. In early twenty-first century, floods indicate increasing trend in magnitude and frequency in the entire basin. For longest period, 1981–2010, the annual maximum flood discharge shows upward trends in upper and middle catchments while downward trends are in eastern and lower catchments of Wabi Shebele Basin. Among these, annual maximum discharge shows a significant increasing trend in middle catchments (i.e. Erer at Hamaro and Gololcha at Wabi junction) and significant decreasing trend in Fafen watersheds at Jijiga and Kebridehar gauging stations. Flood variability and socio-economic damages follow similar trend tendency in the basin. Like variability analysis result in early twenty-first century, the number of peoples affected indicates increasing trend in study area. In such case, one must shift from defensive action against hazards to management of the risk considering the evolution and trends of floods. Due to its nature, floods in transboundary river basin have transboundary consequence which indicates need of cooperation in between riparian countries for Integrated Flood Management (IMF). IMF is approach which adopts the best mix of both structural and non-structural strategies by ensuring a participatory approach and adopting integrated hazard management approaches.