Comparison of demand driven and pressure dependent hydraulic approaches for modelling water quality in distribution networks

Water distribution hydraulic models have been used as a basis for water quality modelling in distribution networks. Experts recognized that a realistic hydraulic model is required to accurately simulate water quality. The aim of this paper is to compare Demand Driven Analysis (DDA) and Pressure Dependent Analysis (PDA) based hydraulic models for simulating water quality in networks for future enhancement of water quality models. The well known EPANET 2 and the newly developed EPANET-PDX (pressure dependent extension) have been used as the DDA and PDA models respectively. Water quality analysis was performed for normal and pressure deficient hydraulic conditions on a sample network from literature. The models provide identical results for normal pressure conditions, but different results for pressure deficient conditions. The differences for the case of pressure deficient condition are significant at the farthest nodes from the source during high pressure deficiency situation with low demand satisfaction condition