Zoning And Network Optimization Research Of City Water Supply System

The optimization of water distribution network is an important issue of water supplysystem. The purpose is to ensure the reliability (including water quantity, pressure and quality)in a limited capital investment. This paper combined the example of Caijiapo Economic andTechnical Development Zone Water Supply Project. Through the depth study of it thendeveloped a more economical, efficient and reasonable water supply network. This will havea great significance to achieve optimal design of water distribution network.Firstly, the paper forecasts the water demand and proposes several commonly usedpredictive models. Through the actual calculation and comparative analysis, we draw theconclusion that the gray model GM（1，1）and VERHULST are reasonably practicable for thewater requirement forecast of Caijiapo Economic and Technical Development Zone.Then, the paper proposes zoning theory based on the traditional partitions on the watersupply system, and summarizes some of the commonly used method of zoning and analysesthe pros and cons of the pipe network. The planning area is divided into five parts based onthe zoning theory. The author simulates the pressure and water age before and after the zoning.The results show that the zoning network can balance water pressure, reduce water age,improve water quality and reduce the dropout rate pipeline network.After that, the author starts from the economic costs, reliability and quality safety, createsmultiple objective functions, puts the hydraulic conditions and regulatory requirements asconstraints then gives the water supply network multi-objective optimization model. Thepaper uses Nondomination Sorting Genetic Algorithm to solve multi-objective optimizationproblems of Water distribution network by analyzing the characteristics of multi-objective.The author proposes the operational processes of network optimization using NSGA by aseries of steps including encoding, population initialization, fitness assignment, geneticmanipulation (selection, crossover and mutation) and termination conditions.Finally, in view of the complexity and impracticability of NSGA optimization algorithm,the author uses EPANET to optimize the hydraulic calculation of Caijiapo Economic andTechnical Development Zone water supply network. The results showed that EPANET optimization are superior to conventional hydraulic calculation methods whether from thereliability or economic indicators of the network.