Optimal Design of Storm Sewer Networks Using Adaptive Genetic Algorithm

In this study for optimal design of storm sewer networks, as an essential urban infrastructure, an adaptive genetic algorithm was developed. In order to utilize the intrinsic storage capacity of the sewer network, the free surface flow constraint was replaced with a new constraint in which no surface flooding was allowed. Furthermore, for the hydraulic simulation of the candidate sewer network, the Storm Water Management Model (SWMM 5.1) was used. The proposed framework was a hydrograph-based optimal design method in which the full dynamic wave model was used for flow routing in the network conduits. The proposed approach was applied for the optimal design of Kianpars storm sewer network, a suburb of Ahvaz city, in Iran. The results were compared with those obtained by the conventional optimal design method (with free surface flow constraint). The comparison showed that the developed algorithm had a high speed and efficiency. Furthermore, the proposed framework (with optimal solution’s construction cost of 474.885 Billion Rials) by utilizing the intrinsic storage capacity of the network could reduce the network construction cost to less than a half of the conventional method cost (with optimal solution’s construction cost of 968.686 Billion Rials).