Uncertainty Analysis of Water Distribution Networks Using linked EPANET-Vertex Method
The analysis of hydraulic behaviour of the water distribution network (WDN) is forefront part of the planning and augmentation of any water supply projects. The desired output parameters such as pipe discharges, hydraulic gradient level (HGL) of nodes, nodal concentrations etc., are normally crisp values assuming crisp input parameters. There are many uncertainties in nodal demands, roughness, length, diameters of pipes, valve operations, water levels in reservoirs, head-discharge characteristics of pumps etc. So the results obtained by traditional method keeping the input parameters as crisp may not give satisfactory performance in practice. Hence taking care of this fact, pipe roughness has been considered as fuzzy parameter in this study. The vertex method has been used to obtain the ordered pair values of pipe roughness at each α-cut level. The hydraulic simulations are done by using EPANET 2 in MATLAB environment. The maximum and minimum values of pipe discharges, nodal HGLs are obtained in single simulation run for each α-cut level. The obtained results are compared with past studies and it is found that current method is effective to analyse the uncertainty problem. This study would help to the decision maker to identify the condition of pipes and consequently the corrective action needed.