Evaluation of Ring Road Drainage Structure (Case Study Megenagna to Bole Road)
No Thumbnail Available
Date
2021-11
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
Addis Ababa University
Abstract
The Purpose of the study is to assess the Performance of Drainage Structures of the Ring Road
from Megenagna to Bole Round About and gives a mitigation measures regarding the drainages
structure along the Road. An exploratory method of research has been used in the study. The study
uses both primary and secondary instruments of data collection. The primary data collection
instruments are observation, measuring the geometry (width and height) of existing cross drainage
structures on the site, photographs that show the existing drainage structure conditions. The
secondary data sources are Rainfall data, soil type, land use, geological map, and DEM data and
QGIS 3.16 (open-source software) uses for watershed delineation of the catchment and extraction
of other important geometric characteristics (i.e length of longest flow path, slope, elevation of the
river and area of the catchment). Hydrological analyses have been carried out by using Soil
Conservation Service (SCS) curve number Method and Rational method, the hydraulic analysis
computed using the HEC RAS (open-source software) that to determine water surface elevations
at all locations of interest for either a given set of flow data (steady flow simulation). The next step
is to check the adequacy of the existing drainage system that suite the site conditions for the
computed discharge, thus based on the hydraulics result, the major river exist around imperial not
functioned well for the 100-return period, so shall be replaced with the new Bridge as span of 15m
and 3.5m, which will accommodate the incoming 100-year discharge. The minor river exists
between Ayat hospital and Imperial Round about, it is not having a significant flow and Can be
retain as it is, only required maintenance and clearing of the channel. Regarding to the storm
drainage all the inlets are not functioned properly due to complete damage of inlets and blockages
of by rubbish/dribs. Therefore, this study recommends to maintain all the damaged inlets and clear
the drainage system that has been blocked by rubbish/ dribs.
Description
Keywords
Hydrological analysis, SCS, Rational method, Hydraulic analysis, Steady flow simulation, 100-return period