Development and Application of Pressure Driven Analysis Model based on EPANET

Hydraulic analysis of water distribution systems (WDS) is divided into two types, one is Demand Driven Analysis (DDA) which applies to a steady state condition and other is Pressure Driven Analysis (PDA) which applies to an abnormal condition. In DDA, it is assumed that available discharge in demand nodes is always equal to the required discharge, and the assumption is suitable for a steady state condition. However, in abnormal conditions such as pipe failure or excess of demand, DDA model may produce unrealistic outputs such as negative pressure, so application of PDA model is required. The Gradient Algorithm used for DDA in EPANET was improved to develop a PDA model based on the Global Gradient Algorithm. Additionally, the developed model was applied to evaluate the emergency water supply plan of a large block system in Yeong Wol. The results showed to 66~100% of the total network demand was available in the emergency scenarios of failure in each reservoir. The developed PDA model is capable to solve negative pressure problem shown in existing DDA model and to analyse evaluation of emergency water supply plan with high reliability.