Hydrological and Hydraulic Analyses of Storm Water Drainage System of Enjebara Town Under the Effect of Land Use and Land Cover Change

Abstract

Urban drainage systems are desirable in all urban areas subsequently their interaction between human daily activity and natural water circulation. As the result of urban expansion and increasing surface impermeability, uncontrolled flooding from storm water drainage system has resulted in damage of small drainage channels, blockage of channels, deterioration of roads and land degradation. Hydrological analysis is thus critical to design road side drains for better management of storm water drainage. This study was conducted to evaluate hydrologic and hydraulic analyses of storm water drainage system for Enjebara town under the effect of land use land cover change. This research work included collection of both primary and secondary data. Landsat images of 1998, 2010 and 2019 for land use land cover classification were used. Geographical information system was used to prepare the classified maps and ground truth observations were also used to check the accuracy of classification. The result show that runoff volumes had increased due to land use land cover changes from 22.48% to 57.8%. In this study design of storm drainage system evaluated by using manning’s and fixing new size of reinforced concrete pipe for existing and proposed area. Bentley Civil Storm V8i dynamic storm water modeling was used to calculates and analyzes hydraulic response of existing drainage system through dependent channel, manhole and outlet to visualize flooding problems. The results obtained from hydraulic condition for storm water is flooding on the street due to peak flow generation from the catchment. According to respondent’s challenge for storm water management in Enjebara town is due to the lack of community awareness, shortage of disposing area, flooding occurrences in the street, blockage of drainage system and lack of clearance storm water drainage lines. Generally, the futures studies should conduct a more detailed study on identification of the flood causative factors to the specific location. Improve the drainage systems along Enjebara town highways, redesign storm water drainage system is essential.