581 - Understanding the Impact of Pressure-driven Modelling in Computing Hydraulic Resilience of Water Distribution Network using Water Network Tool for Resilience (WNTR)

The hydraulic resilience of a water distribution network (WDN) is the capability of WDN to respond to abnormal conditions, such as pipe bursts, leaks, fire-fighting, and power outages, while still meeting demands and pressures at nodes. It is computed using the degree and duration of time in which the network pressures and flows deviate from target or design levels by simulating the WDN’s hydraulics. This analysis helps in understanding the WDN operations and management under normal or abnormal conditions. This paper presents resilience analysis of a real-world WDN, Net6 model example, using Water Network Tool for Resilience (WNTR). Net6 WDN, consisting of 3323 nodes, 1 reservoir, 32 tanks, 3829 pipes, 61 pumps and 2 valves, services a population of 150,000. WNTR is designed to simulate and analyze the resilience of WDNs and supports both pressure-driven demand modelling (PDM) as well as demand-driven modelling (DDM). In the case of DDM, the pressure in the WDN depends on the fixed nodal demands, whereas in PDM the serviced demands are contingent on the actual pressure in the network. Abnormal conditions generally tend to cause pressure deficiency in the WDN. Thus, PDM was found to be more accurate for computing the resilience of the WDN in comparison to DDM. The resilience analysis of WDN based on PDM led to consistent and rational boil water or system pressure advisories, and is proposed for improving pressure management, minimization of loss due to leaks and better understanding of capacity expansion.