Flood Inundation Mapping of Jigjiga-Town and Its Surrounding Environment: Using GIS & HEC-RAS Model

Flood is one of the natural hazards that have negative impacts on peoples and property. It occurs in lowland areas without any sign when excessive rains fall adjacent highland areas. Since flood unavoidable phenomena, adopting protective mechanisms are crucial. This study was conducted Jigjiga town, Eastern Ethiopia with main objective delineating risk For purpose mapping preparation, hydrology hydraulics models been used. Besides, land use /cover change detection analysis has carried out between year 2003 2017. Soil Conservation System (SCS) Curve Number method used as model. Satellite field data collected, filtered finally a geo-database developed GIS environment. Flow river geometry data, which obtained from model prepared using HEC-GeoRAS inputs for HEC-RAS Before running steady flow analysis, correction From study, it found that, expansion built up area agricultural at cost open area. inundation extent maps show increasing aerial coverage return period increases but variation consecutive periods small. The by applying structural control mechanism shows measure reduces considerably also exhibits some part town still undated all periods. observed may lead to increase flooding. among LULC classes under high zone different periods, consist considerable proportion. map can be planning measures future flood.