Assessing the Performance of Integrated Storm Drainage System of Addis Ababa Light Rail Transit and Addis Ababa City Road

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Addis Ababa University


Recently, Addis Ababa is facing with problems related to improper functioning of the drainage systems. This problem become a serious issue during the rainy seasons. Some roads are flooded with usual rain. Light railway transit is introduced to the city since 2014. The railway uses the road drainage network for disposal of runoff generated from the catchment. This project deals with the assessment of the performance of the integrated drainage systems of light railway and road way. The study mainly focus on the cause of flooding on East west line at Sahlite - Meheret round about. The project use EPA SWMM v5.1 for the hydrology and hydraulics modeling in conjunction with ARC GIS 10.1 for the catchment delineation using the manholes as a catchment out let. Fifteen minutes intensity is taken from the IDF curve developed from Bole station for return period of 2,5,10,25,50 and 100 years. The modeling result show that for return period of 10 and 25 years, two manholes were flooded for about 12 minutes and the volume of runoff is about 49 cubic meter for manhole designated as A16 and 7 cubic meter for junction designated as C32, so the project state the remedial measure to be taken to overcome the problems. Pipe connecting the manhole designated as A16-A15-A14 and B13 should be changed from 750 mm to 1200 mm diameter concrete pipe. It is found that there is a differences between the design and construction for pipe connecting A30-A31 and C32 the design provide 750 mm diameter concrete pipe and due to the flooding the pipe where replaced with 3m by 2m rectangular box culvert, and to overcome the common undesirable spreading of the storm water on the surface of the road for common intensity, the manhole inlet and the pipe should be cleaned frequently.



EPA, ARC GIS, SWMM, urban flooding