Combining a Multispecies Water Quality and Pressure-Driven Hydraulic Analysis to Determine Areas at Risk During Sustained Pressure-Deficient Conditions in a Distribution System

Abstract

Realistic numerical models can assist in managing pressure losses in water distribution systems, which is a challenge for water utilities. This paper presents a methodology for simulating the impact of sustained low/negative pressure events on hydraulic and water quality parameters. The developed methodology enables multispecies water quality analysis based on pressure-driven analysis (MSWQA-PDA). This approach has been applied to a large full-scale water distribution system model to evaluate its capability. The spatial variation of water age, chlorine residual, and trihalomethanes (THMs) under normal and sustained low/negative pressure conditions is investigated. Generally, poorer water quality was observed under pressure-deficient conditions compared to normal operating conditions, especially at nodes reaching lower pressure values. The results confirm that under significant sustained low/negative pressure events, demand-driven analysis cannot correctly identify the zones at risk of low and negative pressure, which may lead to unjustified boil water advisories (BWA) for some customers.