Analysis of Water Distribution Network Using Epanet and Vertex Method

Abstract

The analysis of hydraulic behavior of the water distribution network is forefront part of the planning and augmentation of any water supply projects. The analysis of water distribution network 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 vortex method of fuzzy approach. The uncertainties in discharges, hydraulic heads at different α-cuts are evaluated considering the uncertainties in pipe roughness. The results of pipe discharges are found to vary 15% and 30 % whereas the hydraulic heads at nodes vary 0.3m and 3m when the uncertainty of about 8 % in Hazen-Williams coefficient of pipe roughness is introduced in four and five pipe networks respectively. Moreover, when this uncertainty in pipe roughness is combined with other kind of uncertainty as discussed above, would further aggravate the uncertainty in discharges and nodal heads of the pipe. 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.