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Pressure management is a widely adopted technique in the toolset of drinking water distribution system operators. It has multiple benefits, like reducing physical losses in pipe networks with excessive leakage, prolong the expected lifetime of the pipes and protecting home appliances from unacceptably high pressure. In some cases, even legislation compliance can be the motivation behind pressure management: It is mandatory to supply water at the customer’s connection between 1.5 and 6.0 bar in Hungary since 2011. Diaphragm pressure reducing valves are widespread in the drinking water distribution networks. Although, their sensitivity for gas pocket accumulation in the valve house makes hydraulic calibration of these pressure managed areas a challenging task for hydraulic modelers and network operators. This is especially true when more than one inlet is used to supply the same area in order to increase resilience and flow capacity.This paper investigates the hydraulic properties of pressure reduced areas with multiple inlet points. Model calibration using a single valve and minor loss was found insufficient because the additional pressure loss referenced to the pressure setting has a non-quadratic relationship with flow-rate on the discharge side under real-life circumstances. This phenomenon can be handled by using a PRV (pressure reducing valve) + GPV (general purpose valve) in series.

International audience; The paper presents the results of the Battle of Postdisaster Response and Restoration (BPDRR) presented in a special session at the first International water distribution systems analysis & computing and control in the water industry (WDSA/CCWI) Joint Conference, held in Kingston, Ontario, Canada, in July 2018. The BPDRR problem focused on how to respond and restore water service after the occurrence of five earthquake scenarios that cause structural damage in a water distribution system. Participants were required to propose a prioritization schedule to fix the damages of each scenario while following restrictions on visibility/nonvisibility of damages. Each team/approach was evaluated against six performance criteria: (1)time without supply for hospital/firefighting, (2)rapidity of recovery, (3)resilience loss, (4)average time of no user service, (5)number of users without service for eight consecutive hours, and (6)water loss. Three main types of approaches were identified from the submissions: (1)general-purpose metaheuristic algorithms, (2)greedy algorithms, and (3)ranking-based prioritizations. All three approaches showed potential to solve the challenge efficiently. The results of the participants showed that for this network, the impact of a large-diameter pipe failure on the network is more significant than several smaller pipes failures. The location of isolation valves and the size of hydraulic segments influenced the resilience of the system during emergencies. On average, the interruptions to water supply (hospitals and firefighting) varied considerably among solutions and emergency scenarios, highlighting the importance of private water storage for emergencies. The effects of damages and repair work were more noticeable during the peak demand periods (morning and noontime) than during the low-flow periods; and tank storage helped to preserve functionality of the network in the first few hours after a simulated event.

Pressure management is a widely adopted technique to decrease background leakage or to extend the lifespan of the pipe network [1]. In some cases, it is inevitable to deploy multiple pressure reducing valves to supply a particular zone. In order to supply water to the customers with optimal pressure head, the precise setting of the parallel pressure reducing valves’ (PRV) target pressure is required. Steady-state hydraulic models like EPANET has the functionality to simulate pressure loss of a pressure-reducing valve [1]. This can be simulated by adding minor-loss after the pipe, or by modifying the properties of the next link on the downstream side. Either way, the proper setting of the coefficients is essential to calibrate the hydraulic model. In this paper, two non-linear optimization methods were utilized to calibrate the hydraulic model with multiple input values.

Water balance calculation is a well-known and adapted method to analyze district-metered areas (DMAs) of drinking water distribution system. Other application of water balance results can be training dataset for consumption forecast, monitoring and managing water loss. The vast amount of application makes it a very powerful tool, which is in contrary sensitive to the accuracy of the calculation. The uncertainty of flow metering decreases as the length of the time step decreases, however, the uncertainty of stored volume measurement in tanks increases. Investigation of the limitations of water balance calculation in regard to uncertainty is necessary to develop an analytical solution for optimal calculation time step.