جستجوی مقالات مرتبط با کلیدواژه « شبکه توزیع آب » در نشریات گروه « مهندسی آب »

Water distribution networks are one of the vital infrastructures of any country, which one of its main tasks is to deliver good quality water to consumers. These networks are always exposed to various types of threats, and since they are at the end of the water supply chain and are in direct contact with the consumer, the occurrence of quality failure in it can lead to irreparable health, life and social damages. The acceptable performance of water supply networks in terms of quality is dependent on operation and maintenance programs, and risk analysis and management can be mentioned as one of these programs. One of the main components of risk due to the occurrence of quality failure is the probability of failure. In this research, in order to calculate the probability of failure of the quality of water networks, at first, the factors affecting the occurrence of quality failure are identified and with the help of Bayesian networks, the probability of failure of the quality of each pipe is calculated. This work is done in four basic steps: preparing input data, training the Bayesian network, validating it and receiving the output results. In addition, by carrying out sensitivity analysis, four factors consist of pipe type, water pressure, water age and water velocity have been identified as the most effective factors on the occurrence of water quality failure in this area; which controlling them by managers and decision makers of water and sewage companies in the form of risk management programs, the probability of quality failure can be significantly reduced.

Due to the widespread use of computers and measuring equipment in the operation of water distribution networks, a large amount of data is recorded for monitoring and evaluating the performance of water distribution networks and it is used in the modeling and calibration process. The management of these data is very necessary to achieve more accurate models on the one hand and the speed of their processing on the other hand. In this research, the purpose is to process nodal pressure field data to select the best statistical indicators for calibrating the water distribution network model. For this purpose, more than 5500 data collected in 22 stations of Ahar water distribution network and 12 stations of Oshnaviyeh water distribution network have been analyzed. First, by categorizing the data with Sturges experimental method, the probability of the data being placed in the central index categories of average, median, and mode and other categories in different stations in the times of minimum, maximum, and average consumption has been determined, and by summarizing the results, the best central index has been selected. Then, to analyze how the data changes, the minimum and maximum values, the range of variation, and the standard deviation of the data are presented along with the histogram of the categories. The trend of data variations in different stations in the minimum, maximum, and average consumption times shows that there is no specific harmony for data variations, so the maximum or minimum values of the range of variation and the standard deviation of the data are moved spatially in the stations. Also, the process of data allocation to categories shows that in the Ahar water distribution network, most data is allocated to the mode category at about 28.6 percent, followed by other categories at about 26.3 percent. Also, in the Oshnaviyeh water distribution network, the highest allocation is related to other categories with about 30.2 percent, followed by the mode category with 27.2 percent. Considering the multiplicity and dispersion of other categories and the unity of the mode category, the mode category is the best choice for both case studies. In general, by using mode values instead of other central indicators in the calibration of water distribution networks, due to the effectiveness of more field data, more favorable results will be obtained in the construction of the network model.

Given that, observational data have different uncertainties, the calibration of water distribution networks based on a definite value can affect the results of the calibrated model. In this research, the calibration of water distribution networks by considering the uncertainty of nodal pressure has been investigated. For this purpose, first, by generating a series of nodal pressure data using the Monte Carlo method, the Hazen-Williams coefficients of the network have been obtained. Then, by producing a series of Hazen-Williams coefficients, the nodal pressure values have been calculated and the results of the two pressures have been compared. The calibration model was performed using the particle swarm optimization algorithm by linking the EPANET simulator in MATLAB. The proposed method has been implemented on the two-loop sample network and real water distribution network of Sufian city. The results show that the application of node pressure uncertainty in network nodes leads to multiple sets of solutions for Hazen-Williams coefficients of pipes with different variation ranges and standard deviations, which according to the average absolute error of 4 and 3.8 percent between the average nodal pressure in the sample and the real network in the non-deterministic mode with the deterministic mode, the proposed method, can be a more accurate method for calibrating networks. However, it should be noted that there are challenges in the modeling and execution time of calibration models.

The loss of drinking water from water distribution network is one of the problems of Water and Sewage Companies worldwide, which reduces a remarkable part of the company's profit. Therefore, the aims of this research are: determination of strategies and their evaluating criteria for the loss management in water distribution network, prioritization of those strategies and criteria as well as selection of the most effective strategy. This study is a practical research and data gathering was performed via researcher-made questionnaires on snowball sampling based on the idea of 10 experts employed in Water and Sewage Company of Isfahan province. Four strategies of water loss management of water distribution network assessed in questionnaires were selected based on the recommendations of International Water Association, American Water Works Association and the regulations of the non-revenue water committee by the deputy directorate and under supervision of the Water and Wastewater Company of Iran, 2020. Data gathering and analyzing were carried out using paired comparison matrix and analytic hierarchy process by the Expert-choice software. The calculated inconsistency ratio of questionnaires was determined to be 0.02, and therefore the most effective strategy of water loss management of Isfahan water distribution network was determined to be the pressure drop strategy with weight of 0.400. Three other strategies of active leak detection weight 0.259, network repair weight 0.175, and speed and quality of emergencies weight 0.167, were prioritized in the next ranks, respectively. Likewise, the criteria of financial supply weight 0.463 in the first rank, the criteria of technical supply weight 0.289 in the second rank, the criteria of training update weight 0.146 in the third rank, and the criteria of legal supply weight 0.102 in the fourth rank, were prioritized. By increasing the ratio of circular intubation in water distribution network and construction of water storage tanks in the northwestern heights of Isfahan, it is practical to develop the pressure drop strategy in flat districts of Isfahan city leading to the minimum water loss of Isfahan distribution network.

Burst of the water pipe causes soil settlement, which can cause deformation in structures and trees, depending on the type of soil and weight of structures. Damages caused by this phenomenon in Iran are covered by fire building insurance. Fire station is under the supervision of the municipality of Tehran. The analysis of four-year data of urban water pipe burst in District 5 of Tehran has been done. This analysis helps to find places with burst to find a way to preserve trees after water pipes burst. In this research, the bursting of the water pipe, which has caused damage to the building, asphalt, etc., has been selected in the places where the data was available, and then the effect of the bursting of the water pipe on the trees has been investigated and analyzed. In these accidents, trees and utilities around the place where the water pipe burst were examined to eliminate the effects of wind or pests and sunlight, etc., that affect the trees, so that by comparing the pipe burst on them, the area of ​​the urban water pipe burst could have been managed to cause less damage to the trees and utilities.

Paying attention to the conservation of water resources in order to prevent water crises is one of the most important duties of people in the community, including officials. In this regard, the most effective action is water demand management, for which there are different methods. One of these methods is pressure management in order to demand management, which can be used in normal operating conditions as well as in the event of water scarcity. On the other hand, in critical situations where the available water does not meet the total demand, policies such as intermittent water supply are adopted, which are associated with many problems. Therefore, an alternative method is needed to minimize the disadvantages of intermittent water supply,to meet the objectives of demand management and, at the same time is feasible, efficient, and economical. In this research, a combined simulation and optimization model is created by using EPANET2.2 and MATLAB software. With this model, the effects of adopting a water demand management approach using pressure management on the hydraulics of water distribution networks will be investigated. In this research, optimization is done in two approaches. In each case, a different objective function is defined and a genetic algorithm is used for optimization. The developed model has been analyzed on the WDN of Baharestan city located in Isfahan province. The results show that the model is able to reduce the average network pressure by 8 meters by finding the optimal location and adjusting pressure for pressure-reducing valves under normal conditions. Also, during water scarcity, it is able to distribute the available water among the demand nodes considering equity and justice principles. After imposing an 8% deficit on the network, without applying for a pressure management program, 8 demand nodes experienced a shortage between 15 and 30% and 19 experienced a deficit below 5%. However, after optimizing the pressure, only 3 demand nodes experienced a shortage between 15 and 25% and 6 nodes experienced a shortage of less than 5%.

Using pressure reducing valves to reduce the pressure in water distribution systems to the minimum of required value is one of the most effective ways for leakage reduction. Valve opening/closing, switching a pump on/off and water consumption fluctuation by a large consumer cause transient flows. Interference between transient flow and a PRV with constant needle-valve setting may intensify pressure waves in WDS. Applying smart PRVs can limitpressure fluctuation. In this research, Input-output feedback linearization method has been used for smart PRV control. The results of this method have been compared with PRV with CNVS and proportional-integral-derivative controller. A theoretical network taken from references was used to evaluate the proposed methods. Network demands include normal consumers and an industrial large consumer. Water hammer caused by consumption variations, PRV with CNVS operation, IOFL method and PID controllers were modeled in Simulink. PRV outlet head fluctuation in PRV with CNVS is 18 to 28 m in PID controller and in IOFL method are 26 to 28 m. Also, the results showed that the IOFL method has smoother and less fluctuation than PID. Root-mean-square error for PRV outlet head in CNVS, PID controller and IOFL is 1.6, 0.32 and 0.28, respectively. Therefore, IOFL method has less error and better performance than PID. Also, this method has simpler computational operations by converting nonlinear system equations to linear equations.

Water supply networks as a hydraulic system of water transmission and distribution have always been of interest to researchers. The main cause of water transfer in water distribution networks is the pressure head difference between the two points and in case of increasing the standard pressure, the undesirable phenomenon of leakage occurs. Leakage in the irrigation system is economically, socially and environmentally significant. Therefore, leak detection as one of the duties of water and sewage companies in the country has always been a concern. Objectives of the present research includes the detection of water loss points in the water distribution network using the EPANET model and the neurofuzzy method, and compares the two methods and provides a better method for detecting water loss points. In this study, in order to detect leakage in the water distribution network of Mohyabad city of Kerman province, a method based on hydraulic modeling and inverse solution of flow equations to predict the location and amount of leakage in the distribution network Water was introduced using EPANET software and neurofuzzy method with measured values of pressure in a number of network nodes. The results indicate that in the best selected architecture among all tested networks, leakage coefficients resulting from neurofuzzy prediction compared to EPANET modeled values are the most suitable option for modeling and have a coefficient. The correlation between 0.984 and the mean MSE forecast error, equal to zero with the root mean square error (RMSE), 0.0024 (l/s) indicates the optimal forecast accuracy and high reliability of the trained network. The proposed method with a minimum of hydraulic information from pressures, has a good ability to predict the location of leaks in the network and also the use of neurophase method is simple and low cost, in addition, has good accuracy.

Pressure management can reduce leakage and water loss in water distribution networks. Therefore, pressure management is considered as one of the most important ways to reduce costs related to the operation and maintenance of water distribution networks, especially in worn-out networks. Therefore, the pressure of water supplied to consumers should be as low as possible. This approach to reducing pressure in the distribution network by water and wastewater companies has led to an increase in the need for domestic water pressure boosting systems (using pumps and tanks), which in turn increases energy consumption. This discrepancy in the interests of water and wastewater companies and energy consumers highlights the perspective of the water-energy relationship. The aim of this study is to find a solution to optimize the pressure in water distribution networks through the use of domestic water pressure boosting systems while simultaneously minimize the total cost of leakage, pipe burst repairs and energy consumption. In this research, EPANET software is used for hydraulic analysis of the network as well as the use of pressure-based analysis to model as close as possible to the actual operating conditions. The research method has been implemented as a pilot for Baharestan city in Isfahan, and the results show that the optimal pressure is about 48 meters of water column and at a pressure of 41 meters, the costs of water and energy are equal.

Water supply networks are directly related to the economic and social development of urban communities. Due to the rapid increase in population and urbanization, these networks should be properly maintained and rehabilitated. In this paper, an unsupervised learning method with OPTICS density-based clustering algorithm is used to determine the priority areas for rehabilitation. 361 burst event data in one of the Mashhad water network zones were analyzed. The algorithm identified a total number of 16 clusters at 5 different levels of importance. These 16 clusters, which are considered sub-clusters for higher levels, were compared in terms of burst rate. Three clusters with failure rates of 79.1, 62.2, and 50.1 (failures/100 km/year) were introduced as the main priorities for rehabilitation and renovation, respectively. The average burst rate in the whole network was 14.8. The identified clusters were examined in terms of pipe material and diameter and their most affecting factors on the burst rate. The obtained results showed that the OPTICS clustering algorithm has a significant ability to determine priority zones for the rehabilitation plan, by identifying multiple clusters and their according levels. Therefore, the proposed method can be used as a practical and flexible tool to prioritize the rehabilitation process of water networks and identify the main causes of failure events, avoiding complex computational methods or the personal judgment of experts.

Pressure management is an efficient and inexpensive way to reduce leakage in water distribution networks, which is usually possible by systematical operation of valves, pumps, reservoirs, and tanks. In water distribution networks, there are many valves only used during the repairs in the time of accidents. In this paper, a simple approach is proposed for managing pressure and leakage in networks with optimal scheduling of the existing valves’ operation. For this purpose, the optimal locations of the valves are determined by using the valve selection index and their opening rate has been optimized in the minimum, medium and maximum consumption conditions. The optimization was done by combining particle swarm and ant colony optimization algorithm and EPANET simulator within the framework of MATLAB. The proposed method is performed both on a sample and the real network. The results show that there is a significant improvement in the performance of both networks in the average and maximum consumption conditions, so that, the reliability of the Maragheh city network is improved by 22 and 24 percent and leakage by 31 and 20 percent, respectively, compared to the base model. In general, using this approach can improve the performance of real networks by manual programming of a number of selected valves.

A District Metered Area (DMA) is a specified area in which inlet and outlet water at any time is measured. The procedure of forming District Metered Areas is generally comprised of two phases: The clustering phase for automatic detection of the best communities and the physical partitioning phase to optimize the location of gate valves and flowmeters according to the objective function. In this study, the network of Taft city in Yazd province was modeled in Epanet software and by linking EPANET and MATLAB and loading the network configurations, the network was automatically clustered using community structure. In the physical partitioning phase, using the genetic algorithm, the optimal locations of the gate valves and flowmeters was determined by considering the objective function of reduction of standard deviation of DMAs average pressure. The results showed that the community structure algorithm with average daily pressure weight can automatically create appropriate clustering according to the modularity index and uniform pressure in clusters. The optimization of boundary pipes resulted in the reduction of the pressure in different parts of the network, such as areas with pressure higher than the average pressure of the network, and due to the reduced standard deviation of DMAs average pressure caused equitable distribution of network pressure.

Water Distribution Networks (WDN) are amongst the six pillars of smart urban infrastructures which can be managed without or in connection with other smart grids. This research uses an adaptive study to review and compare the approaches and international experiences of smart WDNs. The comparative results initially verify that smart WDN can relatively reduce bursts, leakage, and the reaction time required for operation in comparison with SCADA. In addition, it improves asset management, social awareness about water consumption, the satisfaction of users, water quality, and the revenues of water companies. This study also outlines that smart WDN is a multidisciplinary issue and requires consecutive steps for implementation as described in the Spiral model. This conceptual model is more like a roadmap. It introduces a methodology for upgrading SCADA to smart WDNs and illuminates practical steps, in addition to the short and long term scopes, toward integrated supply and demand management of urban water. Here, the proposed methodology emphasizes pilot studies in different scales and conditions for the validation of integrated software-hardware system prior to any practice.

Leakage in water distribution networks will cause waste of water and reduced pressure. Different leak detection methods are used in the networks among which the Meta-search algorithms have received much attention in the recent years. WaterGEMS commercial software uses genetic algorithm for optimal design and calibrate water distribution networks and detect leakage. In this paper, the WaterGEMS V8i performance in leakage detection using Darwin Calibrator tool was investigated in two hypothetical networks (Poulakis and Aniton). In the Poulakis network where only the node's pressure was put into the software as observational data, the location of leakage was determined at or in the vicinity of the exact location. However, in the Aniton network, where the input discharge was also introduced to the program as observational data, the location and the amount of the leakage were calculated more accurately. These results were similar to the leakage resulted in using the Ant colony algorithm.WaterGEMS is therefore evaluated as a good tool for engineers for estimating the location and amount of leakage in water networks.

One of the advantages of designing water distribution networks (WDNs) as a district metered areas (DMAs) is to identify the leakage in each area by controlling the input and output flow, which of course requires the separating areas and installation of flowmeters between the interconnect pipes of areas. Considering that the most existing WDNs have been expanded traditionally and not as DMA, turning them into DMAs would require huge costs and might not be even practical in some networks. In this paper, a theoretical idea of virtual DMA is presented to identify the leakage in each areas. The innovation of this paper is the ability to transform networks into DMAs using a combination of the graph theory and artificial neural network to find leaks without using a flowmeter. The proposed method, in addition to reducing costs for the flowmeters, also increases the speed of detection of leakage areas. In addition, there is no need to specify the number of leakage nodes before the leak operation begins. The proposed method has been applied for the Balerma WDN in Spain with 443 nodes and 454 pipes for two, three and four simultaneous leaks. The results of this paper show that the proposed theory in this method is able to detect leakage in each area, and this method can determine the number of optimal virtual DMA for each network. In all examples, the leakage area was correctly predicted and the maximum leakage error was about 6.5%.

Water distribution networks are amongst the most important infrastructures of water supply projects, which attracts notable financial credits from the governments. As optimal design can significantly reduce the costs of such large projects, designers always try to minimize the costs while applying all the constraints and technical specifications of the project. Genetic algorithm is one of the most popular approaches for optimizations in the design projects. This research aims at evaluating the meta-heuristic methods used in designing the urban water distribution networks and to assess the genetic algorithm as an optimization mean for such methods. Given the heavy costs associated with water distribution network projects, it is very important how a model perform the cost evaluation. For the current study, the modeling was first performed by WaterGEMS software and the total cost was calculated based on the price list. Then, according to the objective function and cost criterion and with respect to constraints of speed and pressure in the network, optimization was performed and the final cost was obtained. The results of the proposed method showed that by optimization, the investment cost would decrease by about 14% compared to the original plan. Comparison was also made to other meta-heuristic algorithms which confirmed better performance of the proposed algorithm with regards to costs.

Pressure management (PM) is one of the most effective methods of leakage management in water distribution networks (WDNs). In addition to reducing leakage, it provides many benefits for water utilities. The purpose of this paper is an economic analysis of the PM through a comprehensive cost-benefit analysis, taking into account the various aspects of the implementation of PM in WDNs. For this purpose, a mathematical model was developed for evaluating the benefits arising from implementing PM on the reduction of leakage, pipe breaks, active leakage control, water consumption, energy consumption, building damages and the increase of customer satisfaction and the costs of purchase, installation, operation and maintenance, and revenue reduction due to the reduction of water consumption. Using the developed model, the net benefit and benefit/cost ratio can be calculated for each PM scheme. As a case study, the advanced PM system was implemented through the installation of time modulated (TM) and flow modulated (FM) pressure reducing valves (PRVs) in a district metered area (DMA) located in Mashhad city. The net benefit and benefit/cost ration was then estimated by the developed mathematical model. The results showed that the net benefit of PM system through FM is greater than TM and the benefit/cost ratio was obtained 3.7 and 3.2 respectively. The developed mathematical model will assist water managers and practitioners in comprehensive understanding of the benefits and economic justification for implementing PM schemes.

For better utilization of water distribution networks (WDNs), it is recommended that the existing networks be converted into Distinct Metered Areas (DMAs). Due to the complexity of the old networks, the conversion of these networks into DMA is a costly and sensitive issue. In this paper, a model has been developed to optimize implementation of the old networks into DMA by using the graph theory and water distribution system modeling software (EPANET), while the minimum required standard pressure is met and the number of linked pipes between the proposed areas is minimum. The minimum number of linked pipes will minimize the cost of the needed flowmeters. The developed model has been successfully applied for Poulakis WDN with 30 nodes and 50 pipes in different statuses and for the actual Bushehr WDN with about 3740 nodes and 3980 pipes. The output result shows that the developed model, in a satisfactory way, converts water distribution networks into DMAs with respect to the hydraulic constrainsts.

Water distribution network one of the most important and most sensitive urban infrastructures which can be recently with regard to population growth and consumers '' needs to increase with challenges such as reducing the pressure and discharge that are all due to unsuitable design and based on economic goals. In order to overcome these problems when designing an urban water distribution system should always be considered reliability of the network. In this research, to optimize the water distribution networks, two main objectives of cost minimization and maximization of network reliability were considered. To calculate network reliability, the Tondini''s Resilience Index and its hydraulic simulation EPANET 2.0 model were used. Then using the second edition of the evolutionary algorithm based on the strength of the Pareto (SPEA2) and creating a dynamic connection with the EPANET 2.0 hydraulic model in the MATLAB software environment, optimizing the multi-objective of the four water distribution networks including Two-Loop, Kadu, Hanoi networks and D zone of Mashhad. Simultaneous optimization of two main objectives including cost minimization and maximization of the Tondini''s Resilience Index led to the production of optimal solutions in the form of the Pareto front. An optimal solution, called Point C, was introduced using Young''s bargaining method from the final Pareto front of in each of the networks. Selected C solution in two-loop,Hanoi and Kadu networks increased 22.91, 17.13 and 7.41 precent, of the network average pressure compared to its lowest cost in this study (point A). Also, the selected C solution in D-zone network of Mashhad, with an increase of 4.23 precent of the network average pressure compared to the initial design of the consulting company (point D), illustrate that the solution designed by the consulting company would be a dominated solution under the final Pareto front of this study. In this research, the Tondini''s Resilience Index illustrate that, based on increasing nodal pressure, it has the ability to increase the reliability of the network, which This causes the network to be in critical condition or failure of the pipes, with high reliability, providing adequate pressure and discharge in other nodes. Also, the satisfactory performance of the SPEA2 multi-objective algorithm in providing the optimal Pareto front for the issues indicated showed that the design pattern developed in this study could be to provide an optimal set of solutions to the employer to select the points in which each two factors of cost and reliability are combined in a favorable situation.

The process of spatially allocate the water demand is a potential source of errors that should be considered when building the hydraulic simulation model. There are several methods for this purpose and each has limitations and advantages. In the case of existing accurate recording of coordinates for water meters in GIS, there are several base demand automated allocation strategies for modeling the spatial distribution of water consumption in water networks. Where the spatial data for water meters are not available, conventional methods such as Thiessen and LDM (Length Dependent Method) can be used. And if this data is incomplete mixed practices can be used. This study proposed a mixed method named SAWDSL (Spatial Allocation of the Water Demand based on Data of Consumers) that divides the total consumption in subgroups related with corresponding water meters’ recorded. This method assigning the demand of each subgroup into the nearest pipe. The simulation results of WaterGEMS software using SAWDSL, Thiessen and LDM methods, after calibration, were compared to field measurements in zone I1 of Mashhad city. RMSE between observed and simulated pressure with the SAWDSL, Thiessen and LDM methods were determined to be 0.9, 2.3 and 1.4 respectively. That shows if the incomplete data of water meters would have existed and have enough time to use them, SAWDSL method is more accurate than others. Otherwise LDM method is more accurate than Thiessen method.