• Journal of the Korean Society of Hazard Mitigation
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• v.9 no.6
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• pp.133-141
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• 2009

The main objective of water distribution system is to supply enough water to users with proper pressure. Hydraulic analysis of water distribution system can be divided into Demand Driven Analysis (DDA) and Pressure Driven Analysis (PDA). Demand-driven analysis can give unrealistic results such as negative pressures in nodes due to the assumption that nodal demands are always satisfied. Pressure-driven analysis which is often used as an alternative requires a Head-Outflow Relationship (HOR) to estimate the amount of possible water supply at a certain level of pressure. However, the lack of data causes difficulty to develop the relationship. In this study, effective supply, which is the possible amount of supply while meeting the pressure requirement in nodes, is proposed to estimate the serviceability and user's convenience of the network. The effective supply is used to calculate Subsystem Importance Index (SII) which indicates the effect of isolating a subsystem on the entire network. Harmony Search, a stochastic search algorithm, is linked with EPANET to maximize the effective supply. The proposed approach is applied in example networks to evaluate the capability of the network when a subsystem is isolated, which can also be utilized to prioritize the rehabilitation order or evaluate reliability of the network.

• Journal of Korea Water Resources Association
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• v.38 no.7 s.156
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• pp.585-593
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• 2005

Recent concerns regarding protecting, identifying, isolating, redundant routing and dewatering of subsystems of water distribution networks have led to the realization of the importance of valves in these systems. Valves serve two purposes namely, flow and pressure control and isolating subsystems due to breakage or contaminant containment. In this paper, valves are considered from the point of view of subsystem isolation. When a water main is required to be closed, it may be in general necessary to close several other pipes in addition to the broken pipe itself depending on the distribution of adjacent valves. This set of pipes is defined as a segment. In this paper a segment analysis for isolating pipes is present and based on the segment analysis, we suggested the Valve Importance Index and the 7 performance indicators to evaluate the system performance. The suggested methodology is applied to a real network to verify the applicability of the methodology.