scholarly journals Water Network Design Using a Multiobjective Real Options Framework

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
João Marques ◽  
Maria Cunha ◽  
Dragan Savić ◽  
Orazio Giustolisi
Keyword(s):  
Real Options ◽  
Carbon Emissions ◽  
Water Distribution ◽  
Simulated Annealing Algorithm ◽  
Capital Expenditure ◽  
Essential Element ◽  
Distribution Networks ◽  
Hydraulic Pressure ◽  
Trade Offs ◽  
Specific Objective

Water distribution networks (WDNs) are an essential element of urban infrastructure. To achieve a good level of performance, the traditional design of WDNs based on expected future conditions should be replaced by a flexible design, using real options (ROs), that accounts for uncertainty by taking a broader view of possible future options. This work proposes a multiobjective ROs framework that sets out to reduce costs, minimize hydraulic pressure deficiency, and a third objective for minimizing carbon emissions. A multiobjective simulated annealing algorithm is used to identify the Pareto-optimal solutions, thus enabling a trade-off analysis between solutions. These trade-offs show that a low pressure deficit solution is achieved by increasing investment at a much faster rate after a certain pressure deficit threshold (60 m). Also, the pressure deficits can only be reduced by increasing carbon emissions. Finally, this work also emphasizes the importance of including carbon emissions as a specific objective by comparing the results of the proposed model and another one that did not cover the environmental objective. The results show that it is possible to reduce CO2 for the same level of capital expenditure or the same level of network pressure deficits if carbon emissions are minimized in the optimization process.

scholarly journals Leakage Calibration in Water Distribution Networks with Pressure-Driven Analysis: A Real Case Study

2020 ◽  
Vol 2 (1) ◽  
pp. 59
Author(s):  
Joaquim Sousa ◽  
Nuno Martinho ◽  
João Muranho ◽  
Alfeu Sá Marques
Keyword(s):  
Water Distribution ◽  
Simulated Annealing Algorithm ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Real Case ◽  
Calibration Process ◽  
Pressure Step ◽  
Water Companies ◽  
Pressure Driven

Leakage in water distribution networks (WDN) is still a major concern for water companies. In recent years, the scientific community has dedicated some effort to the leakage calibration issue to obtain accurate models. But leakage modelling implies the use of a pressure-driven approach as well as specific data to define the pressure/leakage relationship. This paper presents the calibration process of a real case study WDN model. The process started with pressure step tests, the model was built in WaterNetGen and the leakage calibration process was performed by a simulated annealing algorithm. As illustrated, after calibration the model was able to produce accurate results.

scholarly journals Prediction of pipe failure rate in Tehran water distribution networks by applying regression models

2018 ◽  
Vol 19 (3) ◽  
pp. 695-702 ◽  
Author(s):  
Homayoun Motiee ◽  
Sonya Ghasemnejad
Keyword(s):  
Logistic Regression ◽  
Statistical Models ◽  
Poisson Regression ◽  
Regression Models ◽  
Water Distribution ◽  
Water Distribution Network ◽  
Distribution Networks ◽  
Hydraulic Pressure ◽  
Pipe Failure ◽  
Exponential Regression

Abstract Four statistical models (linear regression, exponential regression, Poisson regression and logistic regression) applied to analyze the variables in pipe vulnerabilities with the objective of finding equations to predict probable future pipe accidents. The most effective variables in pipe failures are material, age, length, diameter and hydraulic pressure. To evaluate these models, the data collected in recent years in the water distribution network of district 1 in Tehran were used, with a total length of 582,702 m of pipes, and 48,500 consumers. The results demonstrate that among the four studied models, the logistic regression model is best able to give a good performance and is capable of predicting future accidents with a higher probability.

scholarly journals Using real options for an eco-friendly design of water distribution systems

2014 ◽  
Vol 17 (1) ◽  
pp. 20-35 ◽  
Author(s):  
João Marques ◽  
Maria Cunha ◽  
Dragan A. Savić
Keyword(s):  
Real Options ◽  
Distribution System ◽  
Distribution Systems ◽  
Water Distribution ◽  
System Development ◽  
Water Distribution Systems ◽  
Distribution Networks ◽  
Embodied Energy ◽  
Real Options Approach ◽  
Materials Used

This paper presents a real options approach to handling uncertainties associated with the long-term planning of water distribution system development. Furthermore, carbon emissions associated with the installation and operation of water distribution networks are considered. These emissions are computed by taking an embodied energy approach to the different materials used in water networks. A simulated annealing heuristic is used to optimise a flexible eco-friendly design of water distribution systems for an extended life horizon. This time horizon is subdivided into different time intervals in which different possible decision paths can be followed. The proposed approach is applied to a case study and the results are presented according to a decision tree. Lastly, some comparisons and results are used to demonstrate the quality of the results of this approach.

Holistic planning methodology for long-term design and capacity expansion of water networks

2008 ◽  
Vol 8 (4) ◽  
pp. 481-488 ◽  
Author(s):  
T. T. Tanyimboh ◽  
P. Kalungi
Keyword(s):  
Water Distribution ◽  
Network Performance ◽  
Water Distribution Network ◽  
Capacity Expansion ◽  
Distribution Networks ◽  
Analytic Hierarchy ◽  
Trade Offs ◽  
Repair Costs ◽  
Planning Methodology

The application of the analytic hierarchy process (AHP) to help select the best option for the long-term design and capacity expansion of a water distribution network is described and applied to a sample network. The main criteria used are: reliability-based network performance; present value of construction, upgrading, failure and repair costs; and social and environmental issues. The AHP has been applied elsewhere on various problems, but not on the long-term upgrading of water distribution networks as proposed in this paper. The pipes are sized to carry maximum entropy flows using linear programming while the best upgrading sequence is identified using dynamic programming. The example demonstrates the effectiveness of the AHP as a systematic tool for assessing pareto-optimal designs based on the trade-offs between multiple criteria. The results demonstrate that the cheapest option is not necessarily the best when other factors e.g. performance and socio-environmental concerns are considered in an explicit way.

Decision support system to divide a large network into suitable District Metered Areas

2012 ◽  
Vol 65 (9) ◽  
pp. 1667-1675 ◽  
Author(s):  
Ricardo Gomes ◽  
Alfeu Sá Marques ◽  
Joaquim Sousa
Keyword(s):  
Water Distribution ◽  
Simulated Annealing Algorithm ◽  
Distribution Networks ◽  
Economic Benefits ◽  
Optimal Number ◽  
Large Network ◽  
Entry Points ◽  
The Difference ◽  
Large Water ◽  
Hydraulic Simulator

This paper presents a new approach to divide large Water Distribution Networks (WDN) into suitable District Metered Areas (DMAs). It uses a hydraulic simulator and two operational models to identify the optimal number of DMAs, their entry points and boundary valves, and the network reinforcement/replacement needs throughout the project plan. The first model divides the WDN into suitable DMAs based on graph theory concepts and some user-defined criteria. The second model uses a simulated annealing algorithm to identify the optimal number and location of entry points and boundary valves, and the pipes reinforcement/replacement, necessary to meet the velocity and pressure requirements. The objective function is the difference between the economic benefits in terms of water loss reduction (arising from the average pressure reduction) and the cost of implementing the DMAs. To illustrate the proposed methodology, the results from a hypothetical case study are presented and discussed.

scholarly journals Placing an ensemble of pressure sensors for leak detection in water distribution networks under measurement uncertainty

2018 ◽  
Vol 21 (2) ◽  
pp. 223-239 ◽  
Author(s):  
Ehsan Raei ◽  
M. Ehsan Shafiee ◽  
Mohammad Reza Nikoo ◽  
Emily Berglund
Keyword(s):  
Measurement Uncertainty ◽  
Water Distribution ◽  
Water Pressure ◽  
Pressure Sensors ◽  
Distribution Networks ◽  
Water Distribution Networks ◽  
Nsga Ii ◽  
New Approach ◽  
Trade Offs ◽  
Selection Of

Abstract Large volumes of water are wasted through leakage in water distribution networks, and early detection of leakages is important to minimize lost water. Pressure sensors can be placed in a network to detect changes in pressure that indicate the presence of a new leak. This study presents a new approach for placing a set of pressure sensors by creating a list of candidate locations based on sensitivity to leaks that are simulated at all potential nodes in a network. The selection of a set of sensors is explored for two objectives, which are the minimization of the number of sensors and the time of detection. The non-dominated sorting genetic algorithm (NSGA-II) is used to explore trade-offs between these objectives. The effect of measurement uncertainty on the selection of sensor locations is explored by identifying alternative non-dominated fronts for different values for sensor error. The evolutionary algorithm-based approach is applied and demonstrated for the C-Town water network.

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