Water Resource
Permanent URI for this collectionhttps://etd.hu.edu.et/handle/123456789/71
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Item ASSESSMENT OF STORMWATER DRAINAGE SYSTEM IN HAWELA TULA SUBCITY, HAWASSA CITY(Hawassa University, 2023-10-28) SINTAYEHU BETISO BERASAThe major goal of this study was to evaluate Tula Town's current storm water drainage system and to provide ideas or engineering solutions that would be able to resolve the current issues. Storm Water Management Model (SWMM), which is a dynamic rainfall runoff simulation model widely applied for urban drainage, was chosen for assessing the triggering factors as well. Due to insufficient drainage network infrastructure and a rise in urban pavement on most urban sub-catchments, this problem developed. The Rainfall depths of sixteen years (2006-2021) of Tula meteorology station were obtained from National Metrological Agency. An intensity duration frequency curve for different return periods (2, 5, 10, 25, 50, 100yrs) formulated by Log person type III distribution method was used as an input for the model due to its slightly better coefficient of determination than other method. The study made use of the SWMM5.2 model and the low impact development control. The calibration and validation of the SWMM5.2 model well-done and its performance was tested by the goodness of fit using the coefficient of determination (R2 ) =0.98, the Nash –Sutcliffe coefficient (NSE) =0.91, and Relative error (RE) =24.13%. The simulated area of the study subdivide to two outlets of the total area of sub-catchment is 70.55ha joint to drainage system infrastructure of 37 nodes, 48 channels, by SWMM 5.2 model. According to the model's results, more than 50% of drainage infrastructure is flooded. At the outfall, total sub catchment runoff has an average flow of 6.0785m3 /s, a maximum flow of 11.39m3 /s, and an overall volume of 222.228*103 m 3 as predicted by the SWMM5.2 model. The town's ongoing drainage issue is helped by the varied implementation of low impact development techniques. In general, the Tula Town urban drainage system evaluation infrastructure overflow studied and regulated for the problem occurred using the best alternative mitigation measures by enhanced low impact development management for all study sitesItem PERFORMANCE EVALUATION OF KEWADO TOWN, DRAINAGE SYSTEM IN SIDAMA REGIONAL STATE(Hawassa University, 2023-04-10) GIZAW HAYISO GUNDULADeveloping countries experience accelerated urbanization without adequate investment in infrastructure. kewado town, like other towns of Ethiopia, have a lot of problems including inadequacy and poor-quality drainage infrastructure. This study was aimed to assess the Performance Evaluation of Kewado town Drainage Systems focused on the western and eastern part of the main road of the town. Both field and historical climatic data were collected and analyzed. Rainfall data for a period of 1990-2019 were used for the study. The methodology employed in this study starts with identifying parent probability distribution for the rainfall intensities with various return periods. This enabled to develop the Intensity Duration Frequency Curve (IDF). The rainfall frequency analyses depicted thatthe log-Pearson III distribution best fits the rainfall intensities as confirmed by the goodness of fit tests. . Rainfall quintiles for a duration of 24hr with a magnitude of 52.4, 62.9, 75.6, 86.9, 95.1 and 103.3 mm/hr. was predicted fora return period of 2,5,10,25, 50 and 100 years respectively The hydraulic dimensions of existing structures were measured in the field using tape meter. The catchmentthat contributes runoff areas, weighted runoff coefficient was delineated using Arc GIS 10.7 tool. Considering the current land use, rainfall intensity and catchment area, the peak discharge was estimated using the rational methods. The Manning equation was used for fixing the dimensions of the storm drainage canals. The adequacy of the existing drainage systems were checked by comparing the estimated runoff with the existing drainage capacity. Hence, most of drainage lines were inadequate to safely dispose of the runoff. Based on the GTZ standard, 60 %, 46 %, 18% and 48% of the existing canals were performed with the severe and light conditions around Mazegaja, Ethiotele, TVT college and Darancho respectively.Illegal disposal of solid & liquid waste into drainage systems, lack of sewer line, unavailability of drainage for some part of town, low community awareness, low mitigation measures and dis- connectivity of drainage were the major problems.. The Stormwater Management Model (SWMM 5.2) was applied to simulate the water levelin the links and junctions by considering the current land use condition