Uncertainty Assessment of Effective Variables on the Water Supply Network based on the Theory of Minimizing Fluctuations in Discharge

Analysis and design of water distribution networks are generally done by considering the magnitudes of the required input data as certain ones, whereas they are not. In this research, uncertainty of pipe roughness and nodal demands are considered in the input data. Pipe roughness is increasing due to aging and nodal demands may vary because of the change of population density and consumption pattern. These variations lead to uncertainties which may change the results of the network analysis such as pipe discharges and nodal pressures. The fuzzy set theory is used in this research. In this regard, the pipe roughness and nodal demands are considered to be fuzzy parameters. The effect of these parameters on the uniformity of flow distribution in the water distribution network which is defined as the standard deviation of the discharges in pipes is evaluated. Maximum and minimum standard deviation are obtained by using the genetic algorithm as an optimization tool.