Storm water discharges are produced when the capacity of the land to retain precipitation isrnexceeded and run-off occurs. Run-off will be influenced by rainfall and intensity and duration,rnantecedent storms and a number of watersheds, and land use characteristics such as slope, soilrntype, and impervious surfaces. rnIn Shire Enda Selassie city rainfall induced flooding during rainy season is a regularrnphenomenon. This may be due to either small size of the drainage canal, an incremental ofrnrainfall, improper design of self-cleansing velocity or increasing of impervious surfaces of therncatchment. Identifying the main problem associated with the drainage system feasibility andrnmaking the system sustainable is important. rnTo Simulate the flooding problem in the city using SWMM model which shows the over loadedrnconduits as well as junctions then select the preferable depth of flow in conduit or junctionrnwithout overflow. Delineation of the area creates by depending on site visiting bounds the regionrnby flow contributes to the junction or drainage. For one control point the total area contributesrnflow is delineated .The total catchment area modeled by SWMM is 56.8 ha, which have 131rnjunctions, 130 conduits (links) and two out fall considers. For this catchment the total runoffrncomputed using model is 9.28m3/s whereas calculated by rational method is 7.4mrn3rn/s. The rnnetwork link simulation a result implies around 22.9 % of links is over pressured due to flood. rnThe total simulation accuracy of the runoff and network systems as assessed by statisticalrnmethods, were RNS, =0.62 and R2 = 0.97. The proposed mitigation measures are modifying therndepth of links for those links. Another case the model cannot simulate the flood problem existsrndue to partially blocked the links, so for this problem continuous maintenance is mandatory.rnTherefore, the effectiveness of different sustainable drainage systems; Trench filter, swale andrngreen roof and enlargement of pipe diameters were evaluated for this case study.