Analysis of flushing-path effects in water-distribution networks

The unidirectional and conventional flushing methods are compared in this study and the water amount and flow velocity at junctions within an EPANET water distribution network are compared. In the unidirectional method, the necessary flow and water pressure for the minimum flow velocity for flushing become greater when pipe diameter exceeds a certain value. Therefore, the maximum length of flushable pipeline decreases. The velocity in a pipeline is not highly dependent on the number of open hydrants; in contrast, the velocity in a pipeline after conventional flushing increases with the number of open hydrants. The hydrant discharge flow is smaller in unidirectional flushing than in conventional flushing. However, the percentage of velocities above 1.0 m/s or 1.5 m/s in a flow is relatively higher in conventional flushing when multiple hydrants are open concurrently. Moreover, preplanning or choice of an exact target area is more necessary for unidirectional flushing than for conventional flushing. In this research, a flushing path that can generate optimum effects with less hydrant discharge flow can be observed when conventional and unidirectional flushing processes are applied to specific components in advance.