HYDROLOGICAL AND HYDRAULIC PERFORMANCE EVALUATION OF STORMWATER DRAINAGE SYSTEMS, OF AWASHO-ALELU KEBELE (01 AND 10) SHASHEMENE TOWN, ETHIOPIA

Abstract

Shashemene town is one of the fastest-growing towns to urbanization and increases the amount of runoff generated from the urban catchment. This study intended to hydrological and hydraulic performance evaluation of stormwater drainage systems, of Awasho-Alelu kebele (01 and 10). Due to urbanization, lack of proper design and management, the transport infrastructure and drainage systems are caused by flooding. Data used for this study were meteorological (rainfall) data, drainage systems dimensions, digital elevation model (DEM). Determining the peak discharge by the rational method using land-use, rainfall intensity and the catchment area of internal all sub-catchments and also the upstream catchment inflow by SCS (CN). These results show, that 78.9% of the drainage systems are not adequate to carry the design flood based on intensity with a return period of 10 years. The other problems lack well-connected and sufficient drainage lines, solid wastes were directly disposed into the storm drainage system and insufficient slope provides which results in decreasing the efficiency of the system. Most drainage systems perform severely degraded are at Farma academy school 54.3%, at new bus station 44.181%, at Malka Oda Hospital 61.6%, at Alelu market 46.5% and Alelu primary School 56.2% were severely degraded