Performance Of Water Distribution Systems Research Articles

Improving the Understanding of Secondary Impacts of Isolation Valve Closures on the Performance of Water Distribution Systems

Improving the Understanding of Secondary Impacts of Isolation Valve Closures on the Performance of Water Distribution Systems

Seismic retrofit optimization of water distribution systems based on the reduction of uncertain damage scenarios

Pre-event interventions, such as retrofit of critical components, are effective strategies to improve the seismic performance and resilience of infrastructure systems. This paper proposes a damage scenario reduction method aims to reduce the computation burden within the seismic retrofit optimization for water distribution systems (WDSs) considering the uncertain damages of pipelines. The optimization framework consists of a multi-objective optimization model for WDS pipeline retrofit and a sequential optimization model for the reduction of uncertain damage scenarios. The multi-objective optimization model is established to minimize the retrofit cost and maximize the seismic performance of WDS. The sequential optimization model, namely weighted optimization-based probabilistic scenarios (OPS + W), was designed to mitigate the computational burden of the multi-objective optimization model, which arises from considering pipeline damage uncertainties through quasi-Monte Carlo (QMC) sampling that generates numerous damage scenarios. The OPS + W selects a few representative damage scenarios from numerous QMC scenarios, aiming to minimize the error of pipeline damage probabilities counted by the representative scenarios, where the error is weighted by the importance of pipeline. The effectiveness of OPS + W is verified through its application in seismic retrofit optimization of two WDS cases and compared with other scenario reduction methods. Application results reveal that the retrofit strategies derived from OPS + W have the highest similarity to those obtained from QMC scenarios while requiring only 3 %–10 % of the computation time compared to using QMC scenarios.

Hydraulic and Utility Performance Evaluation of Ataye Town Water Distribution Network, Ethiopia: case for small towns in developing countries

Evaluating hydraulic and utility performance of water distribution network is a way to check the functionality degree of a system. Water CAD software was used in developing a model and evaluating the hydraulic performance of water distribution system of Ataye Town, Amhara Region, Ethiopia. Both steady state and extended period simulation analysis were carried out to determine hydraulic parameters (pressure and velocity). The model was calibrated using Darwin Calibrator and validity was checked by both correlation coefficient and scatter plot. The utility performance was also evaluated using international water association performance indicators. The simulated result for steady state analysis showed that 68.7% of the nodes operated within optimum adopted pressure (15-60 meter) and 93% of the distribution pipes had a velocity of <0.6 m/s which was a minimum adopted velocity. For extended period simulation 34.3% during maximum demand time and 16.8% during minimum consumption hours had pressure <15meters. 10.8% had negative pressure during maximum demand hours located at Sudan, Selama, and Zigba sefer and 14 nodes (8.4%) during low consumption time had a pressure greater than 60meter, which was a maximum adopted pressure. The areas of high pressure were located at around mosque, Worku Hotel and Hamus Gebaya. The distribution system performs within the adopted pressure at minimum demand time (74.7%) and maximum consumption hours (65.1%). 23.5% of the systems had a velocity of 0.6-2 m/s and the rest had a velocity less than 0.6m/s during high demand time. During low consumption hours, 100% of the system velocity was estimated to be <0.6m/s. Based on the IWA performance indicators, water utility of Ataye Town was evaluated and had low, technical, financial, personnel, and environmental performances. Finally, the distribution system was modified and optimized by providing alternative connections with pressure reducing valves and changing pipe diameter to improve the hydraulic performance and reduce system disruption of the Town.
 Keywords: Extended period simulation; Hydraulic performance; IWA Utility performance; Steady state analysis; Water CAD

Simulation-Optimization of Water Distribution Networks Using ANFIS-Evolutionary Techniques

This study proposes a novel simulation-optimization approach using WaterGEMS and evolutionary hybrid algorithms (ANFIS-PSO and ANFIS-GA) alongside general ANFIS to predict water distribution system performance. Two water distribution networks (WDN), Go-Yang and Gadhra WDN are considered. Velocity prediction depends on pipe diameter and length, while pressure prediction depends on node elevation and demand. Statistical analysis of the three hybrid models revealed that ANFIS-PSO outperformed ANFIS-GA and general ANFIS in velocity and pressure predictions for both WDNs. In the case of Go-Yang WDN, ANFIS-PSO achieved a coefficient of determination (R2) of 0.9884, a root mean square error (RMSE) of 0.0353, and a mean absolute relative error (MARE) of 0.1731 for velocity and ANFIS-PSO achieves (R2, RMSE and MARE) as (0.9812, 0.7256 and 0.03) respectively for pressure. In case of Gadhra WDN, ANFIS-PSO shows the statistical performance (R2, RMSE, and MARE) as (0.9143, 0.0441 and 0.6684) respectively for velocity and ANFIS-PSO achieved (R2, RMSE and MARE) as (0.8929, 0.3875, and 0.02) respectively for pressure. The computational time required for ANFIS is less than 1 min whereas in the case of ANFIS-evolutionary techniques (ANFIS-GA and ANFIS-PSO) it is about nine minutes.

Random Network Model for Assessing the Topological Performance of Water Distribution Systems

A complex network approach enables identifying various topological characteristics of critical infrastructure such as water distribution networks (WDNs). These infrastructure networks are designed based on site-specific conditions and also change over time, so at some point, their topological properties may require improvement, especially in terms of their functions. This research aims to analyze WDNs by establishing a random network with varying proportions of grids (pg). To generate random networks, the properties of the real WDN of a city in South Korea were used as a reference point. Our results indicate that, as the WDN shifted from a loop to a branched structure, the system functioning changed non-linearly with the existence of a threshold below which a network may be effectively improved with low resource inputs. More specifically, the threshold pgs were identified as 0.40 and 0.44 for network efficiency and decentralization. Additionally, the threshold pgs were around 0.22 and 0.23 with respect to availability and normalized efficiency when vulnerability was assessed by removing 1% of nodes whereas those were 0.40 and 0.45 when 10% of nodes were removed. On the other hand, the pg of the real WDN was 0.02 which was significantly lower than the thresholds, resulting in low network efficiency, more centralization and increased vulnerability. This suggests that an increase in pg is required to improve the performance of the WDN in the target area. Our study provides a novel framework for identifying a threshold for the functioning of WDNs. This threshold can be used for designing a new network, as well as for improving existing networks for better topological performance.

Modeling of water age changes in water distribution systems in time and space

The paper presents a particularly important research variant in the process of modelling water distribution systems (WDS), which is the age of water. The age of the water in the pipes is a parameter that determines the freshness of the water. The main goal of the presented research was to analyse changes in water age by observing the basic parameters: pressure and water flow. As a result of the assumed simulations, potential places of secondary contamination were distinguished. The result of solving the situation was the introduction of all works aimed at eliminating and improving the negative changes by much more frequent monitoring of water in this area for physicochemical and bacteriological properties and regular flushing of pipelines. The research is carried out based on the mathematical model of the water supply network. The Epanet software is used as a research tool, which allows modelling changes in the age of water in the entire water distribution system over time. The basis of the conducted research became the time factor, which plays a particularly important role in the process of managing the water distribution system. Taking into account the time, it was observed how much water remains on a given section from the moment it flows from the inlet and is mixed with water already present throughout the network. A number of simulation options were analysed in terms of the operation of the water distribution system, where the key problem was water stagnation. It should be noted that stagnation of water is particularly dangerous in the case of WDS, the obtained results showed visible places on the tested model. Simulations lasting more than 8, 10 days showed a clear deterioration in its quality. The above studies are of particular importance from the point of view of managing the efficiency of the water supply network. The analysis of water in water supply systems, stagnating and thus ageing, shows that the efficiency of the system significantly decreases. The variability of conditions in the water distribution system also makes the performance of WDS, and especially of pumping units, variable.

Evaluation of current and future water demand scenario and hydraulic performance of water distribution systems, a case study for Addis Kidam Town, Ethiopia

The hydraulic performance and future water demand of water distribution networks are major factors affecting the efficiency of water distribution systems throughout the world. Currently, Addis Kidam Town in Ethiopia is facing many water supply challenges. Their existing water distribution system is inadequate experiencing significant water loss, pressure, and flow velocity. All becoming worse with forecast population increases. The main objective of this study was to evaluate the hydraulic performance of the water distribution network considering both the existing water demand, together with forecast future water demand. The study was undertaken in Addis Kidam Town in Ethiopia using static analysis and WaterGEMS V8i software. The data were collected using experiment tests, field observation, focus group discussions, and interviews. Sampling sizes of pipes and junctions of distribution networks were used to evaluate velocity and pressure changes of 12% and 15%, respectively, from high and low-pressure zones. The results of this study indicated that the existing distribution network was designed to supply a population of 8,906; however, the current population was 25,854. The existing system can accordingly not meet current demand. The current system was only supplying 19.5 l/c/d to each family and was only able to supply 45.2% of households. All compounded because water loss of the distribution network was 37.9%. Simulation of existing distribution network at junctions and pipes has both 26.6% and 4.3%, and 2.4% and 29.9% lower pressures and velocities during peak and minimum hourly demand, respectively. Model performance values of RMSE, MAE, R2, and NSE of distribution networks were 0.65, 0.40, 0.96, and 0.82 and 0.56, 0.38, 0.98, and 0.78 during the calibration and validation of pressure, flow, and tank level, respectively. The research recommends a two-phase strategic water distribution system response beginning by upgrading and expanding the water distribution network, to first achieve a supply of 30 l/c/d by 2032, and then lifting this to the 30–80 l/c/d range before 2042. The proposed water management upgrading approach is expected to establish a good water supply for all residential communities of the town facing comparable challenges. In general, this study’s findings showed that the existing water supply system could not meet the present demand, let alone meet future growth demand. The existing modeling highlighted that significant increases in supply are possible by targeting system improvements, together with the need to find additional supply to meet both present and future water demand.

Modeling and optimization of pressure and water age for evaluation of urban water distribution systems performance

Water loss has become increasingly critical as the severity of the water shortage situation has grown in recent decades. One of the options for reducing water loss in urban water distribution networks is pressure management. The study aimed to evaluate and optimize the existing water distribution system in the city. The proposed methodology is an interactive combination process between an optimization algorithm and WaterGEMS V8i to evaluate the performance of the distribution system. It was observed that, 43.80% of nodes (15–60 mH2O), 5.10% of nodes (15 mH2O), and 51.10% of nodes (>60 mH2O) received pressure during peak hour demand. During low demand periods, only 4.4% of nodes (15–60 mH2O) and 95.60% of nodes (>60 mH2O) received pressure. The water age simulation results revealed that, 51.70% of the pipes were received water age <4.8 h, whereas the other 48.3% of the pipes were received water age <8.6 h during peak hour demand. During low demand periods, 45.58% of the pipes had a water age of less than 4.8 h while the other 54.42% of the pipes had water age of 4.8–20 h. The optimization result showed that after optimization, 4.4% of the nodes with optimum pressure increased to 75.18%, and 95.6% of the nodes decreased to 24.82%. Changing the size of the pipe based on the optimization result, and dividing an area into different pressure zones (adding more reservoirs at the far end of the distribution system) are all ways to improve or upgrade the distribution system.

Toward Sustainable Water: Prediction of non-revenue water via Artificial Neural Network and Multiple Linear Regression modelling approach in Egypt

This research paper studied the parameters affecting the non-revenue water in Egypt. The neural model was developed to forecast the NRW ratio before and after network rehabilitation using main parameters and statistical data for various measured district metered areas (DMAs) in Egypt. The non-revenue water (NRW) ratio is a parameter of significant concern for the water distribution system's performance evaluation. Therefore, NRW ratio parameter evaluation requires analysis of variables that influence the NRW ratio. This study aims to offer findings that will lay the basis for sustainable water resources management in Egypt. Consequently, a comprehensive evaluation of water distribution systems and parameters affecting NRW was conducted. The predictive models were developed using the historical data of the water company for various measured district metered areas (DMAs) in Egypt. The automated meta-models were developed at steady-state and over a prolonged period using a series of principles, rules, and constraints. It was based on multi hidden units of feed-forward neural networks trained by the back-propagation algorithm. Thus, the iterative methods of weight adjustment and activation function of Levenberg-Marquardt was used. Two scenarios were assumed, one that has complete data of the DMA investigated while the other assumed total lack of knowledge. Therefore, four models were built to forecast multiple parameters affecting the percentage of non-revenue water. However, three models were combined to reach the final NRW ratio with no historical data. An optimal number of neurons was determined to be 10. Each model result was tested against numeral statistical indicators showing a different level of accuracy. The model results showed high accuracy in NRW final estimation. The performance indicators (i.e., RMSE, MAE, and correlation) also showed that the machine-learning algorithm better identifies complex relationships between different parameters. The models developed in this research can be applied to other DMAs in Egypt. Overall, these findings indicate that the machine-learning model may be adequate for water companies seeking immediate, cost-effective and long-term improvement of their water distribution systems. Results can provide the basis for decision-makers to reduce costs after applying the rehabilitation process upon any new DMA created. This study presents a modelling approach that provides the best prediction of non-revenue water. It allows the use of a model that enables the accurate projection of NRW ratio and approximating NRW in Egypt and elsewhere in similar countries around the world. Thus, it will help decision-makers enhance the overall NRW ratio strategically across Egypt and elsewhere worldwide.

Flexible decision-making framework for developing operation protocol for water distribution systems

Past water distribution systems (WDS) management studies derived operation protocols to maximize WDS reliability by using residual chlorine as the sole surrogate parameter for water quality reliability. Albeit the advancement in mechanistic modeling to examine the WDS water quality, emerging water quality parameters of concern are not yet involved in solving WDS management problems. This paper attempts to overcome this limitation by developing a flexible decision-making framework -integrating EPANET-C, a mechanistic modeling tool for WDS water quality, with Analytic Hierarchy Process (AHP), a multi-criteria decision-making method - to rank the possible water quality parameter-based operating alternatives (organic matter and residual chlorine levels at the source points) for WDS. The uncertainty analysis was incorporated into the mechanistic modeling using the Monte Carlo method to realize insufficient knowledge about the complex biological and physicochemical interactions inside WDS. Six cases, each ranking the alternatives diversely, were applied to reflect the expert judgment impressions on the AHP outcomes. The consistency of the proposed decision-making framework was verified by deriving the operation protocol for two test networks by making trade-offs between the multiple and conflicting microbiological, chemical, and organoleptic quality criteria. The disinfection by-products formation control and taste and odor problems control emerged as the most critical water quality criteria determining the WDS performance under the operating alternatives examined. Altogether, the obtained results suggested the practicality of adopting a flexible operation protocol to maintain the water quality benchmarks over various plausible WDS performance scenarios, ranging from worst to best.

Assessment of accessibility and hydraulic performance of the water distribution system of Ejere Town

AbstractWater is necessary for human health, economic success, and happiness, as well as other developmental goals such as proper diet, gender equality, education, and poverty reduction. Drinking water is a common problem in Ejere Town. The primary goal of this study was to investigate the accessibility of the town's drinking water distribution system. To achieve this research goal, the hydraulic performance of the town's water distribution system and the level of customer satisfaction were assessed. 374 sampled households were randomly chosen from a total of 13,380 to measure the degree of customer satisfaction with the town's water supply services, and the hydraulic performance of the town's water distribution system was analyzed using the WaterGEMS software. Of the 374 customers surveyed for the study, 85 (22.7%) were satisfied and 289 (77.3%) were dissatisfied, implying that the satisfaction levels were below average. The WaterGEMS hydraulic model was calibrated (R2 = 0.94) using measured data from nine randomly chosen nodes. According to the model results, a great amount of the velocity and pressure in the water distribution system was below the minimum recommended limits. These minimum pressures and velocity levels indicate that there is not enough water pressure in the distribution network to reach all parts of Ejere Town. Finally, it was concluded that there was insufficient access to drinking water in the town.

Modeling and Optimization of Pressure and Water Age for Evaluation of Urban Water Distribution Systems Performance

Modeling and Optimization of Pressure and Water Age for Evaluation of Urban Water Distribution Systems Performance

Non-invasive Biofouling Monitoring to Assess Drinking Water Distribution System Performance.

Biofilms are endemic in drinking water distribution systems (DWDS), forming on all water and infrastructure interfaces. They can pose risks to water quality and hence consumers. Our understanding of these biofilms is limited, in a large part due to difficulties in sampling them without unacceptable disruption. A novel, non-destructive and non-disruptive biofilm monitoring device (BMD), which includes use of flow cytometry analysis, was developed to assess biofouling rates. Laboratory based experiments established optimal configurations and verified reliable cell enumeration. Deployment at three operational field sites validated assessment of different biofouling rates. These differences in fouling rates were not obvious from bulk water sampling and analysis, but did have a strong correlation with long-term performance data of the associated networks. The device offers the potential to assess DWDS performance in a few months, compared to the number of years required to infer findings from historical customer contact data. Such information is vital to improve the management of our vast, complex and uncertain drinking water supply systems; for example rapidly quantifying the benefits of improvements in water treatment works or changes to maintenance of the network.

Evaluation of Hydraulic Performance of Water Distribution System for Sustainable Management

Understanding hydraulic performance of water distribution system is crucial for sustainable management of a water supply system. In this paper, a case study of hydraulic performance was evaluated using WaterGEMS hydraulic model integrated with GIS at Tulu Bolo town. The WaterGEMS hydraulic model was calibrated (R2=0.93) using measured data at 10 randomly selected nodes. Results of the analysis show that 92.6% of nodes reached optimized pressure ranging between 15m to 70m and about 1.27% are under permissible pressure while the remaining nodes have above the permissible pressure. The velocity of water in the pipes of the distribution system were found to be within the standard range from 0.2 to 2m/s which covers 82.7% (162 out of 196 pipes). Hence, the implementation of the WaterGEMs hydraulic model integrated approach with GIS enabled to estimate the pressure and velocity of the system with better accuracy and this will be helpful for sustainable management of the water distribution system.

Environmental and economic performance of a water distribution system through a lens of life cycle thinking: A case study of the City of Kelowna

ABSTRACT Water distribution systems (WDSs) are designed to supply water to consumers. Previously, the performance of WDSs was assessed based on the hydraulics, i.e., delivering water with sufficent quantity and good quality under the desired pressure. However, the recent sustainability paradigm has been widely recognized in engineering projects, leading water stakeholders to evaluate WDSs’ performance not only in terms of hydraulics but also considering the environmental and economic impacts. This research proposes an approach to evaluating the sustainability of WDSs at the design stage by applying a life cycle thinking approach. The proposed approach was demonstrated by selecting a small WDS located in the City of Kelowna, Canada as a case study. Twelve alternative designs were created by varying WDS design variables such as pipe diameters, pipe materials, etc. The selected design scenario has 2.5% less CO2 emissions and 12.6% lower cost compared to the baseline design. The developed approach can be applied to WDS having different characteristics to identify conditions, design parameters, and infrastructure components having less environmental and economic impacts.

Models for forecasting water demand using time series analysis: a case study in Southern Brazil

Abstract Technology has been increasingly applied in search for excellence in water resource management. Tools such as demand-forecasting models provide information for utility companies to make operational, tactical and strategic decisions. Also, the performance of water distribution systems can be improved by anticipating consumption values. This work aimed to develop models to conduct monthly urban water demand forecasts by analyzing time series, and adjusting and testing forecast models by consumption category, which can be applied to any location. Open language R was used, with automatic procedures for selection, adjustment, model quality assessment and forecasts. The case study was conducted in the city of Joinville, with water consumption forecasts for the first semester of 2018. The results showed that the seasonal ARIMA method proved to be more adequate to predict water consumption in four out of five categories, with mean absolute percentage errors varying from 1.19 to 15.74%. In addition, a web application to conduct water consumption forecasts was developed.

Development of a data driven FDD approach for building water networks: Water distribution system performance assessment rules

While fault detection and diagnosis is a popular tool in the process industry, its application in building water distribution systems is however still largely absent. In this study, a new set of Water Distribution System Performance Assessment Rules (WDSPARs) were developed to identify common faults in a building water distribution system. The WDSPARs comprise a three-phase process which can be applied using flow and pressure sensor signals obtained in real-time and/or via analysis of historic data in conjunction with knowledge of water distribution system layouts. The performance assessment rules originated from analysis of behaviour in water consumption at two non-residential pilot sites over a 6 month trial. Implementation of WDSPAR at the two pilot studies revealed a number of faults and cases of non-optimal performance which were diagnosed and costed accordingly. The WDSPAR approach is intuitive and can be easily integrated into existing building management systems using sensor data. This study serves as the first practical guide for the implementation of the WDSPAR approach for adoption by large non-residential building end-users. Using the WDSPARs, the case studies outlined in this paper demonstrate 62% savings in water consumption which resulted in energy and carbon emission savings of the order of 50 kW h and 29.9 kg.CO2 per day respectively.

Development of a Fuzzy-Function-Based Performance Indicator for Water Distribution System’s Emergency Condition

Emergency interconnected operation (EIO) between adjacent blocks in a water distribution system (WDS) is one of the most effective countermeasures of a water utility when abnormal conditions (e.g., suspended water supply, pipe burst) occur at a certain location. For improved WDS operation and management, calculating a reliable performance indicator that accurately represents the states of consumers under both normal and abnormal conditions is essential. In this study, a water supply performance indicator (WSPI) was developed for assessing the hydraulic performance of a WDS in terms of consumer usability and satisfaction. A fuzzy function is used to represent the consumer satisfaction with the water supply level, and the satisfaction of different consumers can be adjusted by setting the variables of the fuzzy function. The WSPI can be applied to a hydraulic analysis model based on data from an actual WDS to assess the water supply capacity for each node and the entire network. It can also be used in an advanced pressure-driven analysis model to assess the WDS performance under various abnormal conditions. The proposed WSPI was applied to six suspended water supply scenarios of an actual WDS with and without EIO to assess the effectiveness of this countermeasure.

Emerging Issues and Methodologies for Resilient and Robust Water Distribution Systems

This editorial summarizes the 11 papers published in the Special Issue entitled “Resilient and Robust Water Distribution Systems: State-of-the-Art and Research Challenges” which were classified into five themes related to water distribution systems (WDSs): (1) state-of-the-art review on WDS resilience and robustness (ROB), (2) WDS performance quantification and recovery under earthquakes, (3) criticality analysis and visualization, (4) novel design methodologies, and (5) hydraulic parameter monitoring for WDS rapidity improvement. Following the provision of the number of views and citations of each paper in a brief manner, a paper in category (1) that reviewed recent studies on WDS robustness is summarized. Category (2) covers three papers on improving the WDS capacity to fulfil customers’ demands in the case of an earthquake, a representative catastrophic failure event, while category (3) includes papers on visualization methods to represent the system’s criticality. The studies included in themes (4) and (5) proposed novel design methods and monitoring approaches for improving WDS resilience, respectively. Contributions from each study are described in the context of WDS resilience. We hope that this Special Issue can (1) serve as a reference point from which readers review progress, recent trends, and emerging issues, and (2) shed light on the appropriate future directions of WDS resilience studies.

High-Resolution Energy Intensity Modeling to Improve Water Distribution System Performance

AbstractWater distribution systems can improve their sustainability by identifying and implementing the most energy-efficient scheme for water delivery, but this is difficult to determine for compl...