Sengkang City Runoff Management in Primary Drainage Channels with One Dimensional SWMM model

The main problem in Sengkang City is the occurrence of flood with a height between 0,5 to 1 m in the city center which is an economic area, these is visually caused by the insufficient capacity of the drainage channel to drain runoff water. Topographically, the economic center of Sengkang city is a basin area which is the downstream part of 4 primary channels, namely channels A, B, C, and D. The purpose of this study was to analyze the existing conditions of inundation and volumes and to make modification plans to reduce the area and volume of flooding in Sengkang City. In this study, topographic measurements, data on channel cross-sectional conditions and elevations were carried out as well as data collection on rainfall and land use to be used as input data for the rainfall-runoff SWMM simulation that was appropriate and under existing conditions. Simulations were carried out using rainfall intensity 5-year and 10-year return periods and modifications were made to an additional storage capacity of 2.000 m3 in primary channel A. From the simulation results, the flood volume for 5-year return periods (R5) of 96.375m3 (11 inundation areas), 10-year return periods (R10) of 148.901 m3 (12 inundation areas), and modification of 10-year return periods (R10) of 43.990 m3 (9 inundation areas) with a percentage decrease of 70,46% and reduce of 3 inundation areas.