AAU-ETD AAU-ETD
 

Addis Ababa University Libraries Electronic Thesis and Dissertations: AAU-ETD! >
Faculty of Technology >
Thesis - Civil Engineering >

Please use this identifier to cite or link to this item: http://hdl.handle.net/123456789/2224

Title: CHANNEL STABILTY ANALYSIS -THE CASE OF
Authors: Fantaw, Mengesha
Advisors: Dr. Bayou Channe
Keywords: in Civil Engineering
Copyright: Mar-2008
Date Added: 3-May-2012
Publisher: AAU
Abstract: Rivers dynamically respond to changes in the discharge and sediment supply of catchments. A change of land use and other natural factors in catchments result in changes on sediment supply and discharge. And this process of change of river geomorphology seeking for its equilibrium may affect people and property especially in urban areas located adjacent to rivers. The Kombolcha town, situated on flat land plains in the middle course of the Borkena River is facing a danger of flooding and destruction of properties due to the instability of the Borkena and Berberie River reaches crossing the town. To prevent the loss of lands and properties resulting from the changes in the characteristics of those river reaches, stabilization measures must be employed. For proper design and implementation of any stabilization measures, analysis on stability of these channel reaches must be carried out. So this thesis deals with analysis of the stability of the channel reaches by evaluating their capacity and stability in response to discharge and sediments that are supplied from the catchments. Field investigation and surveying to collect data for channel cross sections, bed & bank material, and the vegetation covers is carried out. Gradations of bed and bank materials are determined in laboratory using sieve analysis. Design discharges of different return periods and quasi unsteady flow data are analyzed from measured maximum daily instantaneous discharge data. Using such flow and existing field data as input, HEC-RAS 4.0 beta version is used for simulation of flow and mobile bed sediment transport Based on the model results which are analyzed using the Meyer Peter Muller and Yang’s sediment transport formula, deposition is observed in almost all of the stations of the Borkena River. And there is deposition at some of the down stream stations in the tributary reach and degradation in the rest. It is also analyzed that the material on the banks is less resistance to the minimum shear induced by the flow, besides much of the stations in the tributary reach are geotechnically unstable. Over flooding still is the problem on upper and lower reaches of Borkena which is resulted from the complex processes of aggradational problems. And stabilization measures are proposed and should be implemented with further engineering, economical and hydraulic analysis for effective and sustainable stabilization of the rivers.
URI: http://hdl.handle.net/123456789/2224
Appears in:Thesis - Civil Engineering

Files in This Item:

File Description SizeFormat
1322536233617171373645652965596215569817.68 MBAdobe PDFView/Open

Items in the AAUL Digital Library are protected by copyright, with all rights reserved, unless otherwise indicated.

 

  Last updated: May 2010. Copyright © Addis Ababa University Libraries - Feedback