Fekersillassie, Daneal(PhD)Urgessa, Kassahun2018-07-232023-11-112018-07-232023-11-112015http://etd.aau.edu.et/handle/12345678/9804Several new road Schemes as well as up-gradation of existing roads are being undertaken by Ethiopian Road Authority for better and faster communication amongst the different parts of the country. Drainage of road is an important aspect of road project for the purposes of safety, speed, maintenance and life span of the road. In early days road drainage structures sized without hydraulic and hydrologic Investigation due to shortage of availability of data as the result; the constructed drainage structure either oversized or in adequate. This thesis outlines the various data to be collected from different sources for proper planning, design of drainage structures. In this thesis the size of each cross drainage structures are assessed by determining the peak discharges of flood which drains towards the location of cross drainage structures along Shishinda-Tepi road. In this study, based on assumption and limitation behind the formula, for each Cross drainage structures peak discharge is determined by either rational, SCS or frequency analysis method. The Conveyance capacity of cross drainage structures is determined by Manning Equation. The study revealed land use/cover hydrological soil group, intensity of rainfall influence that both the peak discharges and runoff volumes reach inlet of drainage structures. In this thesis HEC-RAS models also used to calculate certain hydraulic parameters at Beko and Bitinwuha River crossing under steady state condition the parameters includes steady state water surface profile for 10, 50,100 years return period, stage-discharge curve, depth scour at abutment and pier of structure for above return periods. Key words: Beko and Bitinwuha River crossing, sizing of Cross drainage structures, HEC-RAS model, Peak dischargeenBeko and Bitinwuha River crossingSizing of Cross drainage structuresHEC-RAS modelPeak dischargeThesis