Dynamics of land use land cover and resulting surface runoff management for environmental flood hazard mitigation: The case of Dire Daw city, Ethiopia

Abstract

Study regionThis study was conducted in Dire Dawa city, Ethiopia. Study focusThis study aims to explore the hydrological impacts of land use land cover changes using rational method. As to perform land use analysis, four decade based satellite imagery were analyzed using ERDAS imagine. The hydrological effect of land cover change and respective surface runoff was calculated using rational method. New hydrological insights for the regionThe trend of land use land cover analysis shows that the city has been experiencing significant decrease in forest land with continuous concomitant increases in bare land and settlements through the study period. In response of land use changes, the trend of surface runoff showed continuous increasing trend. The result of focus group discussion confirms that land use change has significantly affected the trend of surface runoff generation. The study also found out that the amount of surface runoff was positively sensitive to forest land and negatively to bare land and settlement classes. To demonstrate the future effect of surface runoff, the study developed worst and best case scenarios. The worst case showed that if the current land use continuous in the coming years, the watershed could receive more surface runoff that threaten the existence of the city. The best case scenario suggested rehabilitation of bare land cover and rooftop rainwater harvesting as promising condition to drop the amount of surface runoff. The output of the study provides environmental friendly surface runoff mitigation strategies that can be adopted at household and community levels.