School of Civil and Environmental Engineering

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Browsing School of Civil and Environmental Engineering by Author "Abdu, Biru"

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    Assessment of Stormwater Drainage System in Assosa Town
    (Addis Ababa University, 2019-01-13) Abdu, Biru; Fiseha, Behulu
    Urbanization is one of the key factors that contribute to urban flooding, which has caused major destruction to the environment, public and private buildings and disrupts public life. In particular, the increase in population and building density influence the change in hydrological characteristics in urban areas. Conversion of pervious areas into impervious areas increases the stormwater runoff quantity dramatically. One way of minimizing urban flooding is to convey stormwater to receiving waters through stormwater drainage systems, which has been practiced in some parts of Assosa town. In Assosa town, drainage problem become an issue during rainy season. This study deals with evaluate the existing stormwater drainage system of Assosa town considering hydraulic and hydrologic parameters in stormwater model. Despite there are many places in the city facing storm drainage problem; Stadium-Mazoria, Stadium-Hibret Bank, Sarbetoch-Anuar, Police commissionEthiopia Hotel and Gebriel-Muluwongel church are areas selected for this study. This stormwater drainage problem has necessitated use of simulation studies for understanding complexities related to the urban flood management; so, the simulation has done by Stormwater Management Model (SWMM). Daily rainfall data is obtained from nearby Assosa meteorology station. The selected extreme daily event was disaggregated into hourly events using reduction formula. Thereafter, the EPA SWMM is used to simulate the response of catchment to rainfall events in which runoff, water depth profile, and outflow hydrograph are obtained. Runoff is also obtained from rational formula for comparison purpose, and for obtaining design intensity a frequency analysis is carried out. LID measures (vegetative swales) also performed to evaluate how LID measures (vegetative swales) influenced urban runoff reduction. The result of this study shows that the problem in the study area caused by insufficient drainage operation, minimum drainage pipe size, improper maintenance and clogging of drainage line by waste material. In addition the results showed that the LID measures are effective in controlling the surface runoff.