dc.description.abstract |
Drainage structures are vital for towns. Recently urbanization is increasing time to time. Due to
this imperviousness of the town area is increasing and flood due to storm water is the cause for
societies complain in the town. Addis Zemen town is the town in Amhara region which is
surrounded by mountains and has a flood risk due to storm water. This thesis is to investigate the
storm water drainage system performance of the town by first delineating the town area and subdivide
into sub-areas. From this nine most flood prone areas are selected. The IDF curve was
developed using 16 years rain fall data collected from Amhara meteorological agency for Addis
Zemen station. Then by using rational method the incoming runoff is determined based on
weighted runoff coefficient due to different land use in each sub-area. Existing drainage channel
capacity was determined in each sub-area using Manning’s equation. The analysis result shows
that the design drainage capacity of the town is adequate to accommodate the incoming runoff
from sub areas. Based on this study the problem in Addis Zemen is due to eroded sediment effect
on the drainage canal capacity from mountains surrounding the town, lack of management like
improper waste disposal way of the town, closing of road side storm water inlets to the ditch or
culverts by different human interface causes and lack of some tributaries to the main drainage
canals. Most of the town area has no drainage canals; this is also other cause of the problem
like inundation of storm water in the town area and series cause of health problems, so the town
planners, sanitary office and policy makers would take in to account sediment from the
mountains, periodic cleaning, maintain the existing drainage canals and construct additional
drains based on the flow direction parallel to the town development plan.
Key word: drainage problem, hydraulic performance assessment, rational method, Addis Zemen. |
en_US |