Peter Chalk Centre

University of Exeter

Stocker Road

Exeter

EX4 4QD

Tel: +44 (0)1392 263637

E-mail: CCWI2019@exeter.ac.uk 

17th International Computing & Control for the Water Industry Conference

1st - 4th September 2019
University of Exeter, UK
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4A Systems modelling

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Raziyeh Farmani

Chair:

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WDSLib 1.1: A Demand- and Pressure-Dependent Simulation Testbed for Water Distribution Systems

Mengning Qiu

Presenter:

Authors:

Mengning Qiu, Mashor Housh and Avi Ostfeld

Hydraulic simulation is an essential tool for design, operation, and management of water distribution systems (WDSs) in industry and research. EPANET 2.0 is one of the most widely used hydraulic simulation toolkits that can be used to perform demand-driven extended-period simulation. Recently, many developments have been carried out to expand the paradigm of the hydraulic simulation and to simplify the WDS network to speed-up the WDS simulation. These developments have been carried out individually using different research systems, on different platforms with different implementation languages. This leads to difficulties in comparing methods, limits the reusability of the code, and creates a barrier for researchers to reproduce and replicate results. WDSLib has been created to address these problems. It implements three WDS solution methods, namely the forest-core partitioning algorithm, reformulated co-tree flows method, and global gradient algorithm. In this study, four additional functionalities have been introduced. These functionalities include (1) the ability to simulate WDS networks with pumps and tanks, (2) the ability to perform extended-time simulation, (3) the ability to perform pressure-dependent simulation, and (4) the ability to perform leakage analysis. These newly developed software functionalities can be easily mixed and interchanged with the existing solution components which allows the user to apply WDSLib to a wide range of realistic use cases.

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Two Phase Design Approach of Water Distribution System Under Water-scarce Conditions

Donghwi Jung

Presenter:

Authors:

Donghwi Jung and Seungyub Lee

In water-scarce and drought conditions, various conservation measures are adopted to minimize total volume of fresh water supplied to customers. An alternative is to treat used water and reuse for non-potable purposes, e.g. flushing toilet, gardening, etc. Because the reused water is delivered through separate lines (purple pipes) for water quality issues, the reused water supply options should be considered at the design phase. This study proposes a two-phase design (TPD) model for water distribution system (WDS) under water-scarce conditions (e.g., drought): the optimal pipe layout is determined in Phase I while the optimal pipe diameter set is sought in Phase II.

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DMA pairing to improve the resilience of sectorised water distribution networks

Aly-Joy Ulusoy

Presenter:

Authors:

Aly-Joy Ulusoy, Filippo Pecci and Ivan Stoianov

Network sectorisation, defined by the isolation of single-feed District Metered Areas (DMAs), is a commonly applied practice in the UK to facilitate leakage and pressure management. By cutting off alternative supply paths, sectorisation however compromises the resilience of water distribution networks. This work investigates the possibility of improving the resilience of sectorised networks by implementing a posteriori DMA pairing. We formulate the problem of optimal DMA pairing as a mixed-integer non-linear problem (MINLP) that we solve using mathematical optimization methods (branch-and-bound). We solve the problem for a small case study network from the literature (Net25) and a large scale operational network (BWPnet) around Bristol in the UK. We also perform a critical link analysis of the resulting configurations to validate the improvement of resilience achieved with DMA pairing. We compare our method to a state-of-the-art MINLP solver (SCIP) and show it performs better on the considered problem instances. The results of our analysis suggest that, although DMA pairing allows to mitigate the impact of network failure events by providing alternative supply paths, there is a trade-off between pressure and leakage management on one side and resilience on the other.

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Calibration of Darcy-Weisbach Roughness Coefficients for an Operational Water Distribution Network

Alexander Waldron

Presenter:

Authors:

Alexander Waldron, Filippo Pecci and Ivan Stoianov

Accurate hydraulic models of operational Water Distribution Networks (WDNs) are critical for a multitude of control, planning, and maintenance activities in the water industry. Thus calibrating WDN models with observed data across the network is periodically required. This study describes the efficient application of a limited-memory quasi-Newton method (L-BFGS-B) to tackle the problem of hydraulic model calibration via parameter estimation for WDNs. A novel formulation for directly calibrating the Darcy-Weisbach head loss model is presented together with the formulation of the Hazen-Williams head loss model. The proposed methods are implemented on a case study of an operational WDN, and demonstrate the robustness of the optimisation; reliably providing an improved set of roughness coefficients irrespective of the head loss model and grouping case.

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Water distribution systems dynamic clustering using graph theory

Avraham Ostfeld

Presenter:

Authors:

Eyal Price and Avraham Ostfeld

Pressure zones in water distribution networks (WDN) are often used to minimize the service pressures supplied to the consumers, such that the overall pressure in the pressure zone is the minimum possible, allowing service pressure to the most critical consumers during the most critical demand periods. During the off-peak demand periods, the critical consumer may differ due to the demand patterns and system topology. Such changes may cause parts of the network to be supplied with pressures that are above the required service pressure, resulting in a potential for higher leakage and higher resulted in maintenance costs. The goal of this research is to recommend the optimal location for pressure reducing valves (PRVs) in the network to minimize the overall pressures over all the examined demand periods, according to a given number of available PRVs. Currently, the suggested algorithm is being examined on a synthetic single pressure zone grid network and will be further examined on several more complex case study networks.

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Optimal DMA Design in Mediterranean Areas by WDNetXL

Daniele Laucelli

Presenter:

Authors:

Daniele Laucelli, Luigi Berardi, Francesco Ciliberti, Antonietta Simone, Gianfredi Mazzolani, Gianluca Perrone and Orazio Giustolisi

This contribution describes the implementation of the above cited strategy in the WDNetXL system and its application on a WDN in Apulian Region (Italy), within the INTERREG Italy-Greece collaboration project named “SUNWATER”, involving water utilities from Italy and Greece. The work answers to the objectives of the project for an integrated, robust and flexible design process for DMA aimed at supporting WDN monitoring, pressure control, leakage reduction and water quality management.

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