Sahilu, Geremew(PhD)Getachew, Hanna2018-07-272023-11-102018-07-272023-11-102016-03http://etd.aau.edu.et/handle/12345678/10267River catchments in the vicinity of landfill site are highly vulnerable to leachate contamination and are exposed to increased risk due to storms and flooding driven by special weather conditions. The objective of this research, thus, was to better understand how the new Sendafa Landfill which is located in the Akaki River catchment might interact with extreme storm events and to investigate associated future risks. The study evaluated potential release of liquid contaminants from the Landfill and examined a broad spectrum of potential conditions that may contribute to these releases. The first step was to investigate how surface water runoff from a storm event at the Landfill contributes to the risk of contaminant release from waste sites based on the source - pathway - receptor approach. Water balance model was used to quantify leachate flow that would be released into the water resource system. Analyses were performed to evaluate the exposure of Akaki catchment to contaminant. Finally, possible mitigation measures were proposed. The result from the risk assessment confirmed that the risk associated with accidental release of leachate from the landfill would lead to contamination of surface water bodies in the vicinity. It was estimated that under 10 year, 100 year and 200 year return period 6 hours duration rainfall, maximum leachate volume of 2160.6 m3\day, 3039 m3\day and 3297.2 m3\day will be generated from the landfill respectively, out of which leachate flow of 824.6 m3/day, 1703 m3/day and 1961.2 m3/day will be above the capacity of the leachate collection system for the respective storm events. This could potentially cause transport of waste solution that may result in a severe pollution risk. Therefore it is recommended that further studies on the determination of risks and its future implications based on a wide range of climatic, environmental and socioeconomic scenarios would give a broader picture of the issues involved and to be able to address them for a better future environment. Key words: Landfill, surface water resources, risk analysis, extreme storm events, leachate, Water Balance MethodenLandfillSurface Water ResourcesRisk AnalysisExtreme Storm EventsLeachateWater Balance MethodThesis