عنوان مقاله [English]
In this paper, a genetic algorithm method is applied for the optimal design of sewer networks. By studying the list price, records and reports of contractors of sewer network construction, a cost function is derived. This function is based on the variables of pipe diameter and slope. Obtained results show the capability of the presented model in optimal design of sewer networks. Optimization of Urmia sewer network using the proposed model leads to 13% decrease in construction cost. One of the advantages of the proposed model is considering the execution aspects and prevention of drops at pipe joints. In this research, proposing a method for calculation of rainwater, impact of rainwater on design of sewer networks is examined. According to the obtained results for the case study of Urmia city, considerable discharge of rainwater (up to 10 times of sanitary sewer discharge) enters into the sewer network. Therefore, considering the rainwater in design of sewer networks would lead to considerable increases in pipe sizes and network costs.