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Title: Assessment of Flood Risk in Dire Dawa Town, Eastern Ethiopia, using GIS
???metadata.dc.contributor.*???: Dr. Dagnachew Legesse
Daniel, Alemayehu
Keywords: Flood;Risk;Hazard;GIS;MCE;Dire Dawa;Dechatu
Issue Date: 26-Dec-2007
Publisher: Addis Ababa University
Abstract: Flooding in any circumstance causes major stresses on the economic, social and environmental regimes of the affected area. The flooding of 5/6 August 2006, however, demonstrated that structural measures undertaken so far are not adequate to withstand flood threats resulting in over 300 fatalities and significant damage to the flood defenses, public infrastructure, housing and livelihoods in Dire Dawa town. This paper studied flood risk analysis of Dire Dawa town and flash flood hazard mapping of Dechatu catchment. To do this an original GIS-based approach was used to build geodatabase for the selected flood hazard layers and elements at risk (land use and population density).Then the important factors were developed to a uniform raster layers with 28.5 m pixel and were masked by the town area in the catchment. Each factor was standardized and then a pair wise comparison method was used to determine the factor weights. Then weighted overlay analysis in multi criteria evaluation (MCE) was used to carry out flood hazard and risk analysis. DEM and mean annual daily maximum rainfall data were used to make flash flood hazard mapping using hydro extension version 1.1 in Arc View 3.2 for Dechatu catchment. Sink filled DEM was used to compute flow direction, flow accumulation, watershed, mean slope, shape factor, and mean precipitation from raster layer generated from mean annual daily maximum rainfall. All these parameters were entered into stream attribute table for characterization. Eight Pour points were computed from the delineated watershed of Dechatu catchment. Accordingly, Lege Dole, Lege Dechatu, Lege Gogeti and Lege Ala were the flash flood hazard wadis in the catchment. The major findings of the paper showed that most of the land use types in the town are within low to moderate flood hazard and flood risk level. With these Dire Dawa town flood risk map and flash flood hazard map, Development of future land use in development policy should be done to decrease the hazard of flooding in Dire Dawa town.
Description: A Thesis Submitted to the School of Graduate Studies In partial fulfillment of the requirements for the Degree of Master of Science in GIS and Remote Sensing in Earth Sciences
Appears in Collections:Thesis - Earth Sciences

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