Development of an Optimal Sewer Layout Model to Reduce Peak Outflows in Sewer Networks

우수관망의 첨두유출량 감소를 위한 최적설계모형의 개발

To achieve the optimal sewer layout design, most developed models are designed to determine pipe diameter, slope and overall layout in order to minimize the least cost for the design rainfall. However, these models are not capable of considering the superposition effect of runoff hydrographs entering each junction. The suggested Optimal Sewer Layout Model (OSLM) is designed to control flows and distribute the node inflows while taking into consideration the superposition effect for reducing the inundation risk from the sewer pipes. The suggested model used the genetic algorithm to determine the optimal layout, which was connected to the SWMM (Storm Water Management Model) for the calculation of the hydraulic analysis. The suggested model was applied to an urban watershed of 35 ha, which is located in Seoul, Korea. By using the suggested model, several rainfall events, including the design rainfall and excessive rainfalls, were used to generate runoff hydrographs from a modified sewer layout. By the results, the peak outflows at the outlet were decreased and the overflows were also reduced.