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In the event that a contaminant is introduced to a water distribution system, utility managers must respond quickly to protect public health. Mitigation strategies specify response actions, such as warning consumers to reduce water activities using the news media and flushing contaminated water at hydrants. The performance of alternative response actions may be influenced by sociotechnical dynamics, as consumer reactions to contaminant exposure and information about the event can change water demands, hydraulics, propagation of a contaminant plume, and public health consequences. This research develops a modeling framework to test and evaluate mitigation decisions that a utility manager may take to protect public health over a wide range of contamination events. An agent-based modeling framework is developed to integrate social behaviors with technical artifacts in a sociotechnical model to evaluate the public health consequences of a water event. Social actors, including consumers and utility managers, are represented as agents and are coupled with a water distribution network model and a news media model to evaluate the performance of response strategies. Strategies for flushing hydrants are encoded as decision trees that specify the location and timing of hydrant flushing, based on the activation of water-quality sensors. The agentbased model is described using the Overview, Design, and Details protocol and is demonstrated for a virtual midsized municipality, Mesopolis. Results compare the effectiveness of flushing hydrants using cautious and adaptive response strategies and the use of the news media to disseminate warning messages. The framework can be applied for cities to evaluate alternative management strategies. [ABSTRACT FROM AUTHOR]

On-demand pressurized irrigation distribution networks (IDN) operating by gravity may face pressure failures especially during the peak period. Several methods have been developed for irrigation sectoring where farmers are organized in turns. In general, the optimization methods used for pressurized systems consider, in the formulation of the problem, energy saving as objective function, which is not suitable for gravity-fed networks. In this study, an optimization model for pressurized IDN fed by gravity was developed to provide an optimal operating strategy based on irrigation periods. The model uses genetic algorithm to assign an irrigation period to each hydrant taking into account the minimization of pressure deficit at the most unfavorable hydrant of the network. The method is applied to a large scale irrigation distribution network in Italy. It shows to significantly improve the hydraulic performance of the network by insuring a satisfactory pressure at all hydrants, under the actual peak demand as well as higher water demands. [ABSTRACT FROM AUTHOR]

The adoption of measures leading to higher efficiencies in the use of both water and energy in water distribution networks is strongly demanded. The methodology proposed combines a multi-objective approach and a financial analysis to determine de optimal design of pressurized irrigation networks which entails the minimization of both the investment cost and operational cost under three operating scenarios that incorporate energy saving strategies: 1- all hydrants operate simultaneously; 2- hydrants are grouped into sectors and irrigation turns are established; 3- the on-demand operation of the network is assumed. This methodology has been applied in a real irrigation network located in Southern Spain showing that the lowest overall design cost (investment and operational costs) is achieved in scenario 2. The comparison of the selected solutions in the three proposed scenarios with the current network design considering the total fulfillment of irrigation requirements showed that operational cost savings between 65% and 76% could be achieved. [ABSTRACT FROM AUTHOR]

As a critical element in preserving the health of urban populations, water distribution systems (WDSs) must be ready to implement emergency plans when catastrophic events such as contamination events occur. A risk-based simulation-optimization framework (EPANET–NSGA-III) combined with a decision support model (GMCR) is proposed in this study to determine optimal locations for contaminant flushing hydrants under an array of potentially hazardous scenarios. Risk-based analysis using Conditional Value-at-Risk (CVaR)-based objectives can address uncertainties regarding the mode of WDS contamination, thereby providing a robust plan to minimize the associated risks at a 95% confidence level. Conflict modeling by GMCR achieved an optimal compromise solution within the Pareto front by identifying a final stable consensus among the decision-makers involved. A novel hybrid contamination event grouping-parallel water quality simulation technique was incorporated into the integrated model to reduce model runtime, the main deterrent in optimization-based methods. The nearly 80% reduction in model runtime made the proposed model a viable solution for online simulation-optimization problems. The framework's capacity to address real-world problems was evaluated for the WDS operating in Lamerd, a city in Fars Province, Iran. Results showed that the proposed framework was capable of highlighting a single flushing strategy, which not only optimally reduced risks associated with contamination events, but provided acceptable coverage against such threats, flushing 35–61.3% of input contamination mass on average, and reducing average time-to-return to normal conditions by 14.4–60.2%, while employing less than half of the initial potential hydrants. [Display omitted] • Hydrant flushing is a practical way to deal with incidents of contamination. • Critical injection nodes, times, and durations are considered injection parameters. • Risk-based analysis using CVaR can address uncertainties about the contamination mode. • Hybrid event grouping-parallel water quality simulation reduces runtime dramatically. • GMCR with a comprehensive viewpoint shows promise in decision-making. [ABSTRACT FROM AUTHOR]

For understanding the leakage plugging and fire extinguishment characteristics of industrial solid waste-based composite foam slurry material (CFSM), the plugging effectiveness, thermal stability, and fire extinguishing and cooling process were analyzed systematically. The experimental device was designed to test the plugging effect of CFSM, when the thermal stability performance monitoring system and fire-extinguishing experimental platform were built to analyze the thermal stability, heat insulation properties, and extinguishment of CFSM, respectively. The results revealed that the surface temperature of CFSM with thickness more than 60 mm would not exceed the critical self-heating temperature of coal (60 °C) before reaching the equilibrium state of condensation heat, thus showing the good thermal insulation effect. The thermal conductivity of CFSM did not exceed 0.098 W/(m·k), indicating the excellent thermal insulation properties. The plugging experiments exhibited that the macroscopic plugging effect of CFSM with thickness more than 40 mm was less different from that of the completely sealed state, and the closed porosity of CFSM reached 74.5%, thus showing the well plugging performance. Moreover, the fire-extinguishing experiments indicated that CFSM could quickly flow and diffuse in burning coal, and exhibiting the well fire-extinguishing properties by covering the fire source, bonding-coating and lasting oxygen insulation. The study would provide an effective basis for the application of fire extinguishment technology using CFSM. • The hydration reaction mechanism of composite foam slurry material was exhibited. • The rheological characteristic of composite foam slurry material was investigated. • The diffusion law and equation of composite foam slurry material was obtained. • The bonding-reinforcement mechanism of this material was revealed. [ABSTRACT FROM AUTHOR]

The existence of fire hydrants in cities is of paramount importance in fighting, mainly to ensure water supply in vehicle stank sused by the fire department. In this sense, the present study a imed to analyse the distribution of such equipment in the south, east and West administrative areas of the city of Natal, Rio Grande do Norte (RN). In the first stage, the equipment was located through the Street View tool Google Earth software. The geographical coordinates were obtained through the Earth view mode and then, conferred in place through satellite navigation device (GPS - Global Positioning System). They were located and recorded 110 hydrants in the three regions. These records, using ArcGIS 9.3 software, was generated a vector file points and through ortofotocartas in scale 1:2000, the geographical location of each piece of equipment was adjusted and converted to projection Universal Transverse Mercator in SAD69 Datum and Zone 25 South. As spatial distribution analysis method, we used the kernel density estimator. The result observed was a geometrically irregular distribution of hydrants in the three administrative areas analysed, with some areas with great concentration and others with total lack of equipment. Thus, the use of this integrated tool to Geographic Information System - GIS proved to beuseful for the spatial location of hydrant sand to guide planning for the installation of new equipment in unmet areas, since it is essential equipment for human security and protect public and private property during fire fighting. [ABSTRACT FROM AUTHOR]

Water utilities excel when they place value on and maintain each system asset in a manner that reflects its value. An effective fire hydrant maintenance program offers a wide range of system benefits. [ABSTRACT FROM AUTHOR]

Cities worldwide have been plagued by water pipe leaks for many decades, resulting in financial losses, public health risks, and environmental impacts. Current practice still relies heavily on periodic and localized inspection rather than long-term continuous monitoring, and since water pipelines are buried underground, leaks can often go undetected for prolonged periods. Noninvasive acoustic-based methods for continuous pipeline monitoring have gained increasing popularity the past decade thanks to the recent advances in sensing and communication technology. Previous research indicates that hydrophones, in particular, are capable of effectively detecting leak-induced acoustic waves inside a water pipe. However, most studies to date have been limited to either controlled or field test-bed settings; hence, findings might not generalize well to real-world complex pipe networks. Through rigorous leak tests conducted in a real water distribution network and an extensive analysis of the field-collected acoustic signals, the current study aims to test the applicability of low-cost, non-intrusive hydrophones attached to fire hydrants for continuous pipe monitoring and leak detection. Continuous wavelet transform, power spectrum, and band power analyses were employed to identify the leak signature and distinguish normal from leak acoustic data in various leak scenarios. Results indicate that the acoustic signals generated by the simulated leaks in this field study are characterized by a consistent increase in the power of the frequency band 150–450 Hz primarily, whereas background noise levels and conditions significantly vary depending on the location of the sensor in the network. Realistic conditions in urban water distribution networks, including background noise, complicated topology, and varying pipe size and material, are still posing significant challenges for cost-effective and widespread implementation of acoustic-based sensors to achieve continuous monitoring in water pipe networks for leak detection. Even though further research and development is required to handle the highly variable conditions of real systems, the low-cost hydrophones tested in this work demonstrated potential in detecting low-flow leaks in simple and complex pipe topologies. [ABSTRACT FROM AUTHOR]

A passive detection method has been proposed in a prior paper to extract key parameters and detect faults using the ambient noise present in water pipeline networks. This paper presents field experiments and data processing results to provide systematic experimental validation of this method. Field experiments were carried out in operational water pipeline networks at the University of Canterbury campus and the Waimakariri District, New Zealand, during which ambient noise was measured by pairs of pressure sensors installed at selected hydrants on pipelines of different materials, network topologies and simulated faults. Auto-correlation and cross-correlation analysis of noise at a single sensor and sensor pairs were carried out to estimate the wave speed and to locate faults in the networks. Data processing results indicate that water usage generating pressure transients are the dominant sources of ambient noise in operational water pipeline networks. This type of ambient noise can also be utilized by the passive detection method to achieve similar wave speed estimation accuracy and fault detection performance as the conventional active pressure wave detection methods. • Field experiments verified that pipe condition can be assessed using ambient noise. • Field experiments verified that pipeline faults can be detected using ambient noise. • Pressure transients caused by water usage are the dominant coherent noise sources. • Wave speed passively estimated by noise is as accurate as traditional active methods. • Blockage and leak faults can be detected by noise auto-correlation with 3 m accuracy. [ABSTRACT FROM AUTHOR]

In this study, we analyze the quality of water hydrant data for estimating housing vacancies based on their spatial relationships with the other geographical data that we consider are correlated with such vacancies. We compare with in-situ vacant house data in several small districts, thus verifying the applicability of the water hydrant data to the detection of vacant houses. Through applying Bayesian approach, we apply the water hydrant data and other geographical data to repeatedly Bayesian updating for the classification of vacant / no vacant houses. We discuss the results of this classification using the temporal intervals associated with turning off metering, fluctuations in local population density, the densities of water hydrants as indicators of vacancies and several other geographical data. We also conduct the feasibility study on visualisation for the estimation results of housing vacancy distributions derived from the fine spatial resolution data. [ABSTRACT FROM AUTHOR]

It has been well documented in specialized literature that, under certain circumstances, the Clément's first demand formula fails in estimating flow in water distribution networks. Through numerical examples, the authors show that the method fails when the number of hydrants supplied by a pipe is small or when the nominal flow rate of the hydrants is nonhomogeneous. In such cases, the normality hypothesis of the design flow rate random variable, an assumption needed by Clément's formula, cannot be made. An alternative method for calculating the design flow rate as a nonnormal random variable is presented. The method works very well in all analyzed examples, mainly because the normality hypothesis is not required. The paper also provides a free-software R-script using freely available software that allows applying the proposed method to user-defined cases. The script helps to understand the method's theoretical basis and can be used as a tool for checking the assumption of normality of data. Therefore, the program allows the applicability of Clément's method to be checked and provides an alternative accurate solution. [ABSTRACT FROM AUTHOR]

Leakage detection in water distribution networks has attracted attention in the water supply industry. To prioritise leak surveys in water distribution networks, a method for estimating area leakage was proposed. This paper shows the results of a real case study to evaluate the proposed method. In two sets of test conditions, the method correctly identified areas where additional leakage of 3.5% of average system flow was simulated by discharge from fire hydrants. By comparing estimated area leakage with and without simulated leakage, the estimation error of area leakage was evaluated to be about 2% of average system flow. [ABSTRACT FROM AUTHOR]

Collecting field data is a vital task for efficiently managing and operating a water distribution system. A field data collection program can be long-term permanent monitoring and/or short-term data logging for capturing hydraulic (pressures and flows) and water quality characteristics. The challenge for water utilities is to determine how many and where to place the data loggers, which hydrant and how many hydrants to flush for flow test, where and how many water quality sensors needs to be placed in a system. This paper reports the development of a unified method and an integrated software prototype for optimizing pressure logger placement, hydrant selection for flow test and conventional flushing, and water quality sensor placement, and also elaborates on the application of the tool for each type of data collection optimizations. It is illustrated that the tool is easy to use and the methods are effective for practitioners to come up with a technically sound field data collection program that can be long-term permanent monitoring or short-term data logging, hydrant flow testing and conventional flushing. [ABSTRACT FROM AUTHOR]

An extensive experimental investigation into the pressure management and resilience of three water distribution network configurations is conducted including: fixed topology zones with fixed outlet pressure reducing valves (PRV), fixed topology zones with flow modulating PRVs, and a dynamic topology. Hydraulic data (128S/s) captures the network behaviour under normal conditions and failure, including artificial bursts generated by operating hydrants and a real burst that affected 8,000 properties. Under normal operation, a dynamic topology lowered pressure by 3 . 1% over a fixed topology with flow modulating PRVs. A dynamic topology maintained the supply of 1,400 properties during the real burst incident. [ABSTRACT FROM AUTHOR]

For a salt or other conservative contaminant contamination event in a water distribution system, opening fire hydrants to flush the system is currently an accepted decontamination method. However, all the contaminated flushed water is discharged to the local surroundings of the fire hydrants and imposes an environmental impact. Another system decontamination alternative can be using a containment pond to catch the contaminated water. To reduce environmental impacts of flushing salt from a water distribution system a comparative life cycle assessment study has been performed for both conventional flushing and for flushing contaminated water into a containment pond. This was performed using SimaPro software for both of these decontamination options and the impacts have been assessed using the IMPACT 2002+ methodology. The results show that environmental impacts can be reduced by 25% for rural areas, 69% for urban roads, 61% for urban lawns, and 64% for mixed land use. In addition, a sensitivity analysis reveals the two most sensitive variables resulting in the finding that a 10% change in the time needed for system decontamination led to a 10% change in environmental impact and a 10% change in the area of land exposed to contaminated water discharge led to an 8% change in environmental impact. • Flushing salt into a containment pond(s) increases environmental impact. • Salt discharge to a pond avoids damage to concrete from regular flushing. • The use of a containment pond in urban areas reduces environmental impact by more than 50% over conventional flushing. • Flushing to agricultural lands or lawns can impose less impact than a combined environment. • Flushing time and exposed land area are the most sensitive variables have the most difference. [ABSTRACT FROM AUTHOR]

In this paper, the focus was on the study of the management of irrigation networks, and a tool was implemented in the MATLAB® environment and developed using the EPANET® toolkit to minimize the energy costs at the pumping station. The tool was validated in an on-demand irrigation network located in Tarazona de La - Mancha (Albacete, Spain). Several scenarios were developed to determine the starting time for each irrigation event and hydrant. The results from the proposed methodology, based on a dynamic pressure regulation, were compared to the current irrigation management practice that used the pressure head as a constant value. On a daily basis, the energy savings achieved ranged from 4 to 8 %, whereas 13-36 % was saved in energy costs. On a festival day, without a high energy rate period, obtaining energy and cost savings close to 7-8 %, and 8-11 %, respectively was possible. Additionally, the savings obtained using the proposed methodology were increased with the use of two variable speed pumps activated sequentially, with the rest of the pumps as fixed, which improved the energy efficiency at the pumping station. [ABSTRACT FROM AUTHOR]

At large international airports, aircraft can be refuelled either by fuel trucks or using dedicated underground pipeline systems. The latter, hydrant refuelling, is considered to be an optimal fuelling method as it increases safety, shortens the aircraft turnaround time and cuts the overall costs. However, at smaller airports, implementation of this system can lead to high investment costs. Thus, the paper discusses the airport size from which this system may be efficient to implement. Various definitions of term “airport size” are assessed. Based on data collection, the hydrant system model is created within the paper. As a result, methodology for assessing the suitability of hydrant system implementation is set. This methodology can be used at every airport using three simple inputs. [ABSTRACT FROM AUTHOR]

A utility may detect contaminant in a water distribution network through water quality sensor information, which indicates that a biological pathogen or chemical contaminant is present in the network. A utility manager should identify actions that can be taken to protect public health, and flushing a contaminant by opening a set of hydrants can be an effective response action. Hydrants should be selected and timed to flush the contaminant; however, accurately ascertaining the characteristics of the contaminant source may be impossible, which creates difficulties in developing a hydrant flushing strategy. This research develops a decision-making approach that is designed to select hydrant flushing strategies in response to sensor activations and does not require information about the characteristics of the contaminant source. A sensor-hydrant decision tree is introduced to provide a library of rules for opening and closing hydrants based on the order of activated sensors. Sensor-hydrant decision trees are developed for a wide range of contaminant events using a simulation-optimization methodology. Potential contamination events are generated using Monte Carlo simulation and are simulated using a water distribution system model. Events are classified based on the order of the activation of water quality sensors in the network, and a noisy genetic algorithm is used to identify hydrant strategies for each class of events. Three sensor-hydrant decision trees are developed to represent risky, risk-averse, and adaptivemanagement strategies. A risk-averse strategy specifies immediate actions to achieve average performance over many events. A risky strategy specifies specialized actions based on the prediction of the plume movement or a decision to wait to receive more information. An adaptive strategy specifies the actions for opening hydrants as each sensor is activated. An adaptive approach does not require predictions of the plume movement, but may result in lower performance due to delays in taking actions. The methodology is demonstrated to develop sensor-hydrant decision trees for a virtual midsized municipality, Mesopolis. [ABSTRACT FROM AUTHOR]

Despite their potential catastrophic impact, transients are often ignored or presented ad hoc when designing water distribution systems. To address this problem, we introduce a new piece-wise function fitting model that is integrated with mixed integer programming to optimally place and size surge tanks for transient control. The key features of the algorithm are a model-driven discretization of the search space, a linear approximation nonsmooth system response surface to transients, and a mixed integer linear programming optimization. Results indicate that high quality solutions can be obtained within a reasonable number of function evaluations and demonstrate the computational effectiveness of the approach through two case studies. The work investigates one type of surge control devices (closed surge tank) for a specified set of transient events. The performance of the algorithm relies on the assumption that there exists a smooth relationship between the objective function and tank size. Results indicate the potential of the approach for the optimal surge control design in water systems. [ABSTRACT FROM AUTHOR]

This study presents an assessment on the suitability of a low‐profile planar antenna for a wireless sensor network (WSN) application monitoring the water supply at fire hydrants (FHs). The antenna must have a low profile so that it can be mounted on the FH lid; it must have an omnidirectional radiation pattern so that it can communicate with base stations at low elevations; and it must operate in the 2.4 GHz industrial, scientific and medical (ISM) band. Measurements show that for the majority of the 2.4 GHz ISM band, the antenna has a return loss of at least −10 dB and efficiency greater than 60%. For the FH WSN assessment, the antenna was deployed as a transmitter mounted on the FH lid above the underground FH chamber and a vertically polarised monopole antenna mounted on a mast at various specified heights above ground level was used to measure the received power as a function of distance. The path loss results were compared with those from a previous deployment, where the FH antenna was located in the FH chamber, and it is found that using the low‐profile antenna reduced the path loss by at least 10 dB over the measured transmitter and receiver separation. [ABSTRACT FROM AUTHOR]