Analysis of Water Distribution Network Using Epanet and Vertex Method

Abstract

The analysis of hydraulic behavior of the water distribution network (WDN) is forefront part of the planning and augmentation of any water supply projects. The analysis of WDN determines the estimation of discharges, hydraulic gradient levels (HGL), nodal concentrations, etc., to fulfill the requirements of population. In the conventional approach of analysis, unique value of pipe discharges and hydraulic heads are obtained. The results so obtained may not give satisfactory performance in practice due to many uncertainties in nodal demands, pipe roughness, lengths, diameters of pipes, water levels in reservoirs, head-discharge characteristics of pumps, etc. In this study, the uncertainty in discharges and hydraulic heads are evaluated using two different pipe networks, the data for which is obtained from literature. Further, the membership function of pipe roughness has been used to calculate the membership function of discharges and hydraulic heads by incorporating EPANET with vertex method of fuzzy approach. The uncertainties in discharges and hydraulic heads at different α-cuts are evaluated considering the uncertainties in pipe roughness. The results of pipe discharges are found to vary between 15 and 30 % whereas the hydraulic heads at nodes vary between 0.3 and 3 m when the uncertainty is about 8 % in Hazen–Williams coefficient of pipe roughness in selected four- and five-pipe networks, respectively. Moreover, when the uncertainty of pipe roughness is combined with other kind of uncertainties as discussed above, would further aggravate the uncertainty in pipe discharges and nodal heads. As a result, the reliability of network would decrease in terms of either meeting the required discharges or the nodal heads to the consumers. This study would help to design the pipe network under the conditions of uncertainty in input parameters.