HYDROLOGICAL ANALYSIS FOR THE DESIGN OF BRIDGE AT CHELKA RIVER ETHIOPIA

Bridges are very important and costly structures lot of birr is spending for the construction hence hydrological investigations are highly recommended for the proper design and durability of bridge. The proposed study area is located at main Degan Town with Rassa Keble and Argoba Woreda Chelka river Ethiopia.The main objective of this study is to carry out hydrological and hydraulics investigations of the Chelka river, to determine its different return floods values in order to find the proposed bridge opening to provide bridge design parameters such as size and location of the bridge and exploring details like geomorphology, soil and land use or land cover, analysis of rainfall intensity. The mean annual rainfall ranges between 400mm-799mm. The mean annual moderate warm temperature is 120oc to 350oc, altitude from 1300-3000m. HEC-RAS (Version-4) software model has been used for determination of proposed bridge layout and the water surface profile. The hydrologic and hydraulic analysis of Catchments delineation is done by GIS Environment by using GIS Software's like Arc View.