Urban Water Supply Systems Research Articles

Developing a 1D-3D model to investigate the effect of entrapped air on pressure surge during the rapid filling of a pipe

An uncontrolled rapid filling or discharging of a pipeline can create compressed air columns in an urban water supply or sewage system. The expulsion of entrapped air out of pipelines is considered as one of the most destructive phenomena. Generally, the air valves are mounted and used to release the air from the pipe. Any failure of the air venting system may lead to a pressure surge inside the pipeline and even damage to the water systems infrastructure. Most of the investigations of multiphase flow during a rapid filling are limited to small distribution systems due to high computational costs. The aim of the present research is to develop a 1D-3D coupled model with the capability to handle multiphase flows. The effects of air pocket length, orifice size and upstream pressure on the flow field and maximum pressure surge inside the pipe are investigated. The classical water hammer equations are solved for the 1D domain using the Godunov scheme while the rest of the system is simulated using the Volume of Fluid (VOF) method. The coupling between 1D and 3D domains are handled using the developed boundary conditions based on flow characteristics. The results of the numerical simulations are compared with available experimental data. The obtained results show that the model can predict the features of the two-phase flow inside the pipeline during a rapid filling. The required computational time decreases by a factor of 4 compared to 3D simulations. This gives the possibility to investigate large scale water distribution or drainage systems.

Approaches to the implementation of hydraulic electronic models of centralized water supply systems

Introduction. The analysis of the Russian normative and methodological documents, as well as research articles, has identified gaps in the development and practical implementation of hydraulic electronic models of existing water supply systems. The user guide of the software products, used to design these models, merely demonstrates the capabilities of software modules and misses the outcome of their application in certain cases. Decree No. 782 issued by the RF Government on September 5, 2013, being the document that regulates the development of electronic models of water supply systems, lists the requirements applied to software. The document, titled Construction regulations SP 31.13330.2012, has the requirements applicable to the hydraulic analysis of water supply system designs. This suggests that the Russian regulatory environment has no document that contains the basic requirements governing the development and detailing of hydraulic electronic models of water supply systems. This is an essential problem of urban utility networks, since the hydraulic electronic model is the basis for any further actions in strict accordance with which a development plan of a centralized urban water supply system is designed.
 Materials and methods. The article has a scientific review of the problem of design of electronic hydraulic models of centralized water supply systems and basic principles and approaches to electronic model generation.
 Results. The co-authors provide a detailed description of a methodology used to develop a model of urban water supply systems as well as the requirements set by foreign standards.
 Conclusions. Model development and calibration is structured in the article. This information is needed to adjust the characteristics of the designed model to a water supply system in operation.

Defender–attacker–operator: Tri-level game-theoretic interdiction analysis of urban water distribution networks

The aim of this paper is to advance the field of network interdiction analysis by introducing an application to the urban water distribution networks (WDNs), deploying protective resources against intentional attacks. The resource allocation problem for urban water supply systems is considered as a three-player (i.e., defender–attacker–operator) game, in which the attacker aims to maximize disruption impacts via interdicting water plants in the network, the defender aims to minimize the worst-case disruption impacts achieved by the attacker while the system operators fulfill the water demand in the residual urban water supply network. Considering the operating characteristics of the water supply network, we adopted the method of hydraulic analysis in the third level to obtain its reliability, and use this as the game equilibrium index of the first two levels. An effective modified variable neighborhood search method is devised to obtain the solution to the game. Finally, a case study was conducted based on the data of water supply network of a certain city in China to evaluate the effectiveness of protection resources against intentional attacks.

Impact of the Pumping Regime on Electricity Cost Savings in Urban Water Supply System

The main purpose of the presented research is to raise the efficiency of pumping stations’ operational work by developing a model for reducing energy costs in urban water supply systems. Pumping systems are responsible for a significant portion of the total electrical energy use. Significant opportunities exist to reduce the pumping energy through smart design, retrofitting, and operating practices. Today, considering the increase in pumping energy prices in water conveyance systems, the problem of optimal operation of pumping stations is very actual. The optimal operation of pumping stations was determined using a Genetic Algorithm Optimization (GAO) to achieve the minimum energy cost. The paper presents a novel management model for the optimal design and operation of water pumping systems on a real case study for the town of Gonabad in Iran. To achieve this goal, three days in a year were selected randomly. The results indicate that the proposed mode in conjunction with a GAO is a versatile management model for the design and operation of the real pumping station. Modeling results show that optimization with a GAO reduces power consumption by about 15–20%.

Considerations on the efficient functioning of the urban water pumping stations

Current urban water systems aim to ensure hydraulic and water quality parameters for all consumers connected to the water distribution network, with the highest possible efficiency. This corresponds to reduce primary energy consumption and a responsible control of drinking water sources in order to supply water to urban areas. Most of the time, a low efficiency of water supply systems is due to the following factors: inefficient operation, poor maintenance, incorrect sizing and unmetered water consumption. This article analyzes the efficiency of the solutions applied in the pumping station as a component part of the water supply systems. The case study focuses on the operation of pumps in water supply systems and presents the analysis of the relationship between water consumption and electricity of a pumping group in an urban water supply system. This paper is a first step in order to obtain global parameters for energy optimization of the urban water system.

Field Measurements and Numerical Modeling of Hydraulic Transients in HDPE Pipeline with PRV Interaction

Pressure reducing valves (PRVs) and high-density polyethylene (HDPE) pipes are commonly used in urban water supply systems (UWSS). To study the joint effect of PRV and viscoelasticity on transient wave propagation, extensive experiments have been conducted in a field-scale reservoir-PRV-viscoelastic pipeline system covering a wide range of internal pressure heads (∼10 to 60 m) and air temperatures (12°C–33°C). In addition, a one-dimensional method of characteristics (MOC) based model that incorporates a PRV model and the generalized Kelvin-Voigt (K-V) model for pipe viscoelasticity is developed and validated against field data for the first time. The simulated transient pressures are in good agreement with field measurements. The K-V parameters exhibit a clustered distribution and the mean value for each element can provide a satisfactory simulation. The PRV in hydraulic transients can be interpreted as a quasi-dead-end with a self-adjusting opening, and causes additional positive pressure wave reflections that are gradually damped due to viscoelasticity. The dynamic changes in PRV opening, head loss, pressure wave reflection, and transmission induced by an incident pressure surge are predicted. Due to the joint action of PRV and pipeline viscoelasticity, the pressure oscillations in an intact pipe settle to a value that is considerably higher than the initial PRV set pressure. In a leaking pipe, the downstream pressure reverts to the original set pressure within a few wave cycles. Leaks can be detected by wave reflections in the time domain signals. The existence of leaks is also found to be associated with the the amplification and damping of the frequency response function (FRF) of the system at certain resonance peaks. This study provides new insights into wave propagation in HDPE pipeline with PRV interaction and an original data set for validation of leakage detection methods.

Risk Assessment of Water Treatment Plants Using Fuzzy Fault Tree Analysis and Monte Carlo Simulation

Urban water supply, transmission, and distribution systems are considered as the basic infrastructures of each community. Deficiency of water resources in system leads to lack of some subscribers’ access to safe water at any time. The water treatment units have a high potential for massive crisis and importance of sustainable performance in water treatment plants, due to their special role in high quantity and quality water supply even in critical situations, requires a comprehensive approach in assessing and increasing the reliability. A comprehensive approach in assessing the performance of water treatment plants and reducing their vulnerability can lead to cost reduction of inappropriate performance in critical situations and also a focus on the most important vulnerable parts of water treatment plants to decrease their vulnerability, as well as cost-effective budgeting in recovery programs. In this research, due to the uncertainties in the input information, two methods of fuzzy fault tree analysis (FFTA) and fault tree analysis (FTA) based on Monte Carlo simulation were evaluated in Jalaliyeh water treatment plant in Tehran, and results of both approaches were compared in terms of uncertainty analysis. The results indicate the low to moderate failure risk in the treatment plant in both approaches and a small difference between results in both cases. Failure probability of top event for FFTA and Monte Carlo-based FTA methods is 0.194 and 0.27, respectively. In the basic event rating, it was found that threats such as inappropriate reservoir design, power equipment failure, transfer pipe failure, and inappropriate maintenance of the pumps play the major role in treatment plant failure.

Study on the Application of Smart Water System in Urban Water Supply

The construction of intelligent water system can realize the rational application purpose of urban water resources, and also can improve the level and quality of water service. In this system, by combining information resource system with intelligent management system, it provides data information for management staff, which is conducive to more scientific management and ensures the good application of intelligent water system in urban water supply system. This paper analyzes the application of intelligent water system in urban water supply, including the importance of intelligent water system, the key points of system construction and suggestions for effective application, and gives priority to the important influence and value of intelligent water system. Then, it explores how to build and apply intelligent water system, and tries to make every effort to make in-depth and comprehensive analysis, It provides theoretical reference for relevant enterprises and staff to practice and apply the system, and ensures better application of the system, so as to promote the good development of urban water supply. It is hoped that the discussion in this paper can provide a powerful help for the further promotion of intelligent water system in urban water supply system.

Theoretical justification and development of technical means to ensure environmental safety of urban water management systems

Ecological safety of water intakes in urban water management systems and the creation of comfortable living conditions for people can be ensured only with a comprehensive solution to the problems associated with improving water quality when it is taken from the source, preserving biodiversity in the water body, protecting against blue-green algae, zebra mussel and mechanical pollution. The water intake technological complex as a part of the natural-technical system (NTS) specialized type “Natural water environment - Urban water management complex - Urban water supply system” (“NWE - UWMC - UWSC”), as the main multifactorial technogenic component, includes various types of hydraulic structures and protective devices interconnection, interaction and relationship (IIR), which ensure the environmental safety (ES) of the urban economy. The studies have established that the functional IIR between the structural elements of the “UWMC” in the composition of this NTS type “NWE – UWMC - UWSC” determines the generalized design and technological solutions, which determine the complex of protective measures to ensure the ES preservation of health and the urban population life quality. Based on the results of complex (theoretical, laboratory, full-scale) studies, constructive and technological solutions have been developed to preserve the diversity of ichthyofauna (juvenile fish, etc.) in the water body, to ensure the protection of the water intake bucket from bottom and suspended sediments, sludge and floating objects coming from the water body, from toxic blue-green algae and fouling with zebra mussel of structural elements and technological equipment as part of the urban water management complex. Functional sequence of IIR structural and technological solutions (STS-1, STS-2, STS-3) between themselves (Fig. 1) provides regulatory requirements for environmental safety.

Urban Water Supply Management and Water Supply Safety Countermeasures

With the development of social economy, the scale of towns is expanding, the quality of life is improved, and the water supply safety is more and more concerned. Urban water supply as the key component of urban infrastructure construction, in order to ensure the safety of water quality, to avoid different nature of water quality pollution, to different management objects and system analysis, understand the factors affecting water quality, using scientific management methods, construction of perfect urban water supply security and quality assurance management system. And establish a certain period, regularly control urban water supply pipes and auxiliary facilities, find and control and deal with problems in time. The transformation of urban pipe network should promote and apply new pipe materials, which can avoid the secondary pollution of pipe materials. To sum up, the current water supply system management and urban water supply system is serious, backward management technology and supervision technology, aging water supply pipe network and insufficient capital investment all affect the management of water supply system and water supply safety, relevant departments should pay attention to and control, and do a good job in problem solving and control

Учет неопределенности водопотребления при оптимизации перспективных схем развития си-стем водоснабжения и водоотведения

The design of urban water supply and disposal systems is associated with overcoming various uncer-tainties of an economic, technical, natural and anthropogenic nature. Among them, the estimated loads for water consumption and discharge are the most significant. If water supply and disposal systems are designed and built for loads higher than the actual values, the water and runoff flow rates will cause quiescent area, pipeline silting and even plugging. If the actual load exceeds the designed load, this will lead to significant hydraulic pressure losses, overstated operating costs and considerable equip-ment wear. The risks involved with overestimating or underestimating the design loads are very high, as both would require reconstruction and immense financial investments. To minimise such risks, we propose a methodology based on a multi-stage and adaptive project implementation with minimum risks when making a decision at each step. A numerical study demonstrated the efficiency of the proposed methodology and its conformity with the domestic design process and development of water supply and disposal systems. This method allows the optimal way of system development to be chosen ac-cording to the life cycle costs.

RESILIENCE EMERGENCY STRATEGIES FOR URBAN WATER SUPPLY SYSTEM UNDER EMERGENT WATER POLLUTION EVENTS

Aiming at the problem of fluctuations in the supply capacity of urban water supply systems caused by sudden water pollution incidents, an emergency strategy is proposed from the perspective of system resilience. The system resilience is defined from both economic and social aspects, and a single objective mathematical model under the constraints of limited resources is established. The CPLX software was used to solve the emergency dispatch and resource allocation plan. The simulation results show that the economic resilience of the water supply system can be improved by increasing the capacity of the backup water source; the social elasticity value of the water supply system in the rich areas is usually low; stable and continuous water supply It can improve the social resilient value of the water supply system. Finally, the relevant data of the water pollution incident in Harbin were simulated to verify the effectiveness and practicability of the model, and provide a basis for government departments to formulate relevant policies.

A new performance analysis model for urban water supply systems evaluation

A new performance analysis model for urban water supply systems evaluation

Water Engineering at Precolumbian AD 600–1100 Tiwanaku’s Urban Center (Bolivia)

The pre-Columbian World Heritage site of Tiwanaku (AD 600–1100) located in highland altiplano Bolivia is shown to have a unique urban water supply system with many advanced hydraulic and hydrological features. By use of Computational Fluid Dynamics (CFD) modeling of the city water system, new revelations as to the complexity of the water system are brought forward. The water system consists of a perimeter drainage channel surrounding the ceremonial center of the city. A network of surface canals and subterranean channels connected to the perimeter drainage channel are supplied by multiple canals from a rainfall collection reservoir. The perimeter drainage channel provides rapid draining of rainy season rainfall runoff together with aquifer drainage of intercepted rainfall; water collected in the perimeter drainage channel is then directed to the Tiwanaku River then on to Lake Titicaca. During the dry season aquifer drainage continues into the perimeter drainage channel; additional water is directed into the drainage channel from a recently discovered, reservoir connected M channel. Two subterranean channels beneath the ceremonial center were supplied by M channel water delivered into the perimeter drainage channel that served to remove waste from the ceremonial center structures conveyed to the nearby Tiwanaku River. From control of the water supply to/from the perimeter drainage channel during wet and dry seasonal changes, stabilization of the deep groundwater level was achieved—this resulted in the stabilization of monumental ceremonial structure’s foundations, a continuous water supply to inner city agricultural zones, water pools for urban use and health benefits for the city population through moisture level reduction in city ceremonial and secular urban housing structures.

Hydraulic Engineering at 100 BC-AD 300 Nabataean Petra (Jordan)

The principal water supply and distribution systems of the World Heritage site of Petra in Jordan were analyzed to bring forward water engineering details not previously known in the archaeological literature. The three main water supply pipeline systems sourced by springs and reservoirs (the Siq, Ain Braq, and Wadi Mataha pipeline systems) were analyzed for their different pipeline design philosophies that reflect different geophysical landscape challenges to provide water supplies to different parts of urban Petra. The Siq pipeline system’s unique technical design reflects use of partial flow in consecutives sections of the main pipeline to support partial critical flow in each section that reduce pipeline leakage and produce the maximum flow rate the Siq pipeline can transport. An Ain Braq pipeline branch demonstrated a new hydraulic engineering discovery not previously reported in the literature in the form of an offshoot pipeline segment leading to a water collection basin adjacent to and connected to the main water supply line. This design eliminates upstream water surges arising from downstream flow instabilities in the two steep pipelines leading to a residential sector of Petra. The Wadi Mataha pipeline system is constructed at the critical angle to support the maximum flow rate from a reservoir. The analyses presented for these water supply and distribution systems brought forward aspects of the Petra urban water supply system not previously known, revising our understanding of Nabataean water engineers’ engineering knowledge.

Urban water supply automation – today and tomorrow

AbstractAutomation is a collection of a whole set of theories and methods to make a system work automatically as intended, in our case the urban water supply system. A critical feature of automation is the feedback principle: a sensor is measuring a certain variable, e.g. a concentration; a computer tests that the measurement is valid; a computer algorithm calculates and decides what should be corrected; a pump or valve or some other device transforms the decision to action. All of this is untouched by human hand. The ‘intention’, or the goal, must be provided to the controller. The key component of automation is the system that can represent any component or process in the water supply system and even the complete system. Automation technology always must be combined with a true understanding of people at all levels. Otherwise, there is a high risk for misunderstandings and failures. Three categories of problems are highlighted, where automation can contribute: uncertainty, feedback, and complexity. A key challenge is the handling of disturbances. Integrated management of the whole urban water cycle will be required in future urban areas to acquire sustainable operations. Automation is a crucial condition to make integration possible in complex systems.

Multi-objective optimization of energy and greenhouse gas emissions in water pumping and treatment.

A large part of operating costs in urban water supply networks is usually due to energy use, mostly in the form of electricity consumption. There is growing pressure to reduce energy use to help save operational costs and reduce carbon emissions. However, in practice, reducing these costs has proved to be challenging because of the complexity of the systems. Indeed, many water utilities have concluded that they cannot practically achieve further energy savings in the operation of their water supply systems. This study shows how a hybrid linear and multi-objective optimization approach can be used to identify key energy consumption elements in a water supply system, and then evaluate the amount of investment needed to achieve significant operational gains at those points in the supply network. In application to the water supply system for the city of London, the method has shown that up to 18% savings in daily energy consumption are achievable. The optimal results are sensitive to discount rate and the financial value placed on greenhouse gas emissions. Valuation of greenhouse gas emissions is necessary to incentivise high levels of energy efficiency. The methodology can be used to inform planning and investment decisions, with specific focus on reducing energy consumption, for existing urban water supply systems.

State-of-the-art review on the transient flow modeling and utilization for urban water supply system (UWSS) management

AbstractIn the context of smart city development and rapid urbanization worldwide, urban water supply system (UWSS) has been of vital importance to this process. This paper presents a comprehensive review on the transient flow research for UWSS management. This review consists of two aspects as follows. The first aspect is about the development and progress of current transient theory, including transient flow models, unsteady friction and turbulence models, and numerical simulation methods. The other aspect is about the utilization and application of transient-based methods for effective UWSS diagnosis and management, including leakage, discrete and extended partial blockages, unknown branch, and other defects in water pipelines. A total of 228 publications have been reviewed and analyzed in this paper. In addition to the state-of-the-art progress and achievement of the research on transients, the advances and recommendations of future work in this field are also discussed for the development and management of next-generation smart UWSS in the paper.

A combined simulation-optimisation modelling framework for assessing the energy use of urban water systems

Reliance on new and alternative water supply sources is a desirable option for upgrading existing and ageing urban water system infrastructure that is no longer able to cater for steadily increasing water demand. This transformation will increasingly involve the use of decentralised, more complex and energy intensive urban water systems. Modelling capability that takes a holistic systems approach to optimize the dynamic interactions between water and energy is needed to evaluate the performance of fit-for-purpose water supply systems for the urban sector. This paper presents a simulation-optimisation model to concurrently simulate and optimize an urban water supply system based on minimum energy use when water of alternative quality is supplied to different users on a ‘fit-for-purpose’ basis. The model uses a System Dynamics approach to simulate the energy use of different water supply systems in the form of stocks and flows combined with a Genetic Algorithm (GA) technique to optimize energy use while satisfying all the water demands. The comprehensive model framework is built on a Matlab/Simulink® platform. Life Cycle Energy Assessment (LCEA) is used to generate the embodied energy use variables which are input to the simulation-optimisation model. The model is sufficiently flexible to accommodate water supply systems of variable spatial scales and analyse water and energy use at variable time scales. The application of the modelling framework on the Aurora urban development estate, Australia, shows that the model produces essential information about the water supply and energy use intensity according to specified criteria.

Impact of coronavirus (COVID-19) spread-prevention actions on urban water consumption

This article aims to assess the impact of coronavirus (COVID-19) spread-prevention actions on water consumption, based on a case study in Joinville, Southern Brazil. Residential water consumption data, obtained through telemetry in two periods (before and after a governmental action imposing quarantine and social isolation), were analyzed. Complementarily, the analyses were also applied to the commercial, industrial and public consumption categories. For the analysis, Wilcoxon and Kruskal-Wallis non-parametric tests were applied and Prais-Winsten regression models were adjusted. The results of the Wilcoxon test show that there are significant differences between the analyzed periods, indicating a water consumption drop in the commercial, industrial and public categories, and an increase in the residential category. The regression model results confirm the effect of the restrictive actions in reducing consumption in non-residential categories. The results also indicate an increase in water consumption, which was steeper in apartment buildings than in houses, whether isolated or grouped in condominiums. A weak association was found between the variation in water consumption and the spatial distribution of buildings. Understanding water consumption related aspects is important to gather essential information to ensure the urban water supply system is resilient in a pandemic situation.