Flood inundation mapping and mitigation options in data-scarce region of Beledwayne town in the Wabi Shebele River Basin of Somalia

Title : Flood inundation mapping and mitigation options in data-scarce region of Beledwayne town in the Wabi Shebele River Basin of Somalia

Abstract:

Somalia has experienced extreme flash floods in recent years across the arid regions, causing tremendous loss of lives and property. However, the flood magnitude, depth, and frequency of occurrence are not yet quantified. This is mainly due to the scarce datasets in the area. In this study, integration of observed and Climate Hazards Infrared Precipitation (CHIRP) satellite rainfall products and remote sensing raster data was used to improve hydrological model simulation outputs. The Hydrologic Engineering Center, namely HEC-HMS and HEC-RAS models, were used to simulate the rainfall-runoff processes and flood inundation, respectively. The land use, soil, slope, and Digital Elevation map (DEM) were used to set up the models and generate outputs. The HEC-HMS model calibration results depict that the model is able to reproduce the observed streamflow The simulated flows generated by the model predicted good agreement with the observed flow with values of 0.79, 0.74, 0.78, and 0.78 evaluated through the Nash and Sutcliffe Efficiency (NSE), Runoff Volume Error (RVE), coefficient of determination (R²), and percentage error of peak flow (PEPF), respectively. The HEC-RAS model result indicates that the maximum flood depth and velocity were obtained at the floodplain area. The peak flood at 50, 100, and 200-year return periods using the General Extreme Value (GEV) distribution revealed 384m³s^-1, 409m³s^-1, and 434m³s^-1, respectively. The 100-year peak flood discharge in a specific part of the river revealed a flood depth of 7.53m. The provision of Levees as mitigation measures revealed a reduction of the flood extent by 35% and suggested them as possible flood protection measures for the study area.

Biography:

Omer Ahmed is a leading voice in climate and environmental research, specializing in the unique challenges faced by Somalia and the wider Horn of Africa. With an MSc in Hydraulic and Hydrology Engineering, he/she brings a rigorous technical foundation to his/her work as a Senior Lecturer at the University of Hargeisa and as an independent consultant.

Omer's expertise sits at the critical intersection of water security, climate change adaptation, and ecosystem preservation. His research portfolio includes in-depth analysis of hydrological variability under climate stress, the assessment of anthropogenic drivers of land degradation (including overgrazing and deforestation), and the development of sustainable water resource management frameworks for arid and semi-arid regions. At the University of Hargeisa, he/she is instrumental in shaping the curriculum and mentoring students to tackle complex environmental problems.

Committed to translating research into impact, Omer actively engages with local communities, NGOs, and policymakers. His work is dedicated to devising evidence-based strategies that address the interconnected crises of climate change, environmental vulnerability, and human security, making him/her a key contributor to building a more resilient and sustainable future for Somalia