Optimization of urban stormwater and sewage systems

This research investigates the possible use of optimization procedures in designing sewage and stormwater collection systems by considering the special cases and problems that could be encountered in real world designs. The use of genetic algorithms is decided through a screening study in an attempt to find an optimization technique that is suitable to the problem under consideration. The project making process of sewage and storm water systems is evaluated in two phases. In the first phase, the directions of the flow in the pipes are optimized through a process called direction optimization. In this phase, approximate cost functions taken from the appropriate literature are used by adding some penalty costs. The aim of the use of penalty costs is to direct the optimization procedure in the desired way. The optimization process in the first phase, called the direction optimization, has specified the flow direction in each pipe at minimum cost network. The directions specified in this phase are exported as inputs to the second phase. In the second phase, another optimization process called hydraulic optimization has been performed to find the diameter and slope of each pipe. At his time, real cost values are used together with the directions specified in the first phase. The optimization processes mentioned above have been undertaken through the use of a newly coded computer program that is specific to this research. The system developed have been applied to the two real world examples. The optimization trials made for the case studies have yielded more acceptable results than those obtained without optimization procedure.