CoordenaÃÃo de AperfeiÃoamento de Pessoal de NÃvel Superior / Este trabalho apresenta um modelo computacional para o dimensionamento otimizado de mÃnimo custo em redes de distribuiÃÃo de Ãgua. O modelo à um complemento do sistema UFC4 (MÃdulo para dimensionamento de redes de abastecimento de Ãgua). O modelo utiliza a tÃcnica dos Algoritmos GenÃticos e a simulaÃÃo hidrÃulica à feita pelo EPANET. Foram feitas vÃrias simulaÃÃes variando individualmente cada parÃmetro do algoritmo para se obter um melhor desempenho em termos de convergÃncia, tempo de processamento e qualidade final das soluÃÃes. Seu resultado à comparado ao obtido pelo LENHSNET para a mesma rede. O custo comparado foi o de implantaÃÃo das tubulaÃÃes. O modelo proposto se mostrou satisfatÃrio para o dimensionamento otimizado de redes de distribuiÃÃo de Ãgua. / This work presents a computational model for the dimensioning of optimized minimum cost of water distribution network. The model is an addition to the system UFC4(module for dimensioning water supply networks). The model uses the technique of Genetic Algorithms and the hydraulic simulation is done by EPANET. Multiple simulations have been made individually varying each parameter in the algorithm to achieve better performance in terms of convergence, processing time and the final of the quality solutions. Its results is compared to that obtained by LENHSNET for the same network. The cost compared was the of implementation of pipes. The proposed model has proved satisfactory for optimized dimensioning of network.

Atualmente a avaliação das perdas de água, nos sistemas de distribuição, é feita com base em equações empíricas, que utilizam informações, agrupadas e totalizadas, de uma área. Isto torna necessária sua subdivisão em frações cada vez menores, na busca da fração mais crítica. Neste trabalho, é apresentada uma avaliação da eficácia do uso de modelos de simulação hidráulica na obtenção das informações necessárias para a elaboração de um diagnóstico de perdas de água, com uma metodologia prática para o uso de modelos com este objetivo. Apresenta uma classificação dos trechos de rede em três categorias A, B e C, que facilita a priorização dos trechos mais críticos facilitando a análise por meio de gráficos de pareto e mapas temáticos. Demonstra que a adoção da simulação hidráulica no estudo das causas de perdas de água, nos sistemas de abastecimento, é uma ferramenta eficaz e permitirá às empresas de saneamento, uma melhoria na gestão operacional, que garante a sustentabilidade da empresa, a economia dos recursos humanos, econômicos, e principalmente, os hídricos. / Currently water losses evaluation in distribution systems, is based on empirical equations using information, grouped and totaled, covering whole area. Thus, becomes necessary to subdivide the area into smaller and smaller fractions, searching for the most critical part. This study presents, the effectiveness evaluation of the hydraulic simulation models, use to obtain the information necessary in elaboration diagnosis of water losses, with a practical methodology for using models for this purpose. Shows a pipe classification in three categories A, B and C, its began possible analyses with pareto graphics and thematic maps. Demonstrates that hydraulic simulation adoption is an effective tool in the study of water loss in supply systems. It will allow companies an operational management improvement, ensuring the sustainability of the business and economics of human, financial, and especially, water resources.

O trabalho apresenta uma proposta de metodologia para diagnóstico de sistemas de distribuição de água através da elaboração, passo a passo, e de uso de simuladores hidráulicos apoiados por aplicativos de geoprocessamento. Utilizando-se de dados reais como o histórico operacional de vazamentos dentro da região adotada num intervalo de tempo, espera-se fornecer ao analista um instrumento de análise visual do comportamento hidráulico do setor em função de uma escala progressiva de ocorrências, mapeada através de cores, permitindo avaliar a qualidade do modelo hidráulico como um todo, corrigindo desvios para que o mesmo reproduza eficientemente o comportamento real da rede de distribuição. Através deste, esperase avaliar as consequências da variação das pressões e vazões durante o dia, subsidiando tomadas de decisão, permitindo avaliação das opções e a redução de riscos e investimentos desnecessários. / The work presents a proposed methodology for diagnosis of water distribution systems through the development, step-by-step and hydraulic simulators use supported by geoprocessing applications. Using real data and operational history of leaks within the region adopted a time interval, is expected to provide the analyst a tool for visual analysis of the hydraulic behavior of the sector according to a progressive scale of occurrences, mapped through colors, in order to evaluate the quality of hydraulic model as a whole, correcting deviations so that it efficiently reproduces the actual behavior of the distribution network. Through this, it is expected to evaluate the consequences of variation of pressure and flows during the day, supporting decision-making, allowing the evaluation of the options and the reduction of unnecessary risks and investments.

Considerando a necessidade do controle mais efetivo dos sistemas de distribuição de água para abastecimento, a calibração constitui etapa fundamental a ser trilhada para garantir a reprodução do comportamento dos sistemas sob as mais diversas condições operacionais. Apesar da importância da calibração e da diversidade de modelos construídos com esse propósito no ambiente acadêmico, essa prática não tem sido amplamente utilizada pelas companhias, que demonstram certa relutância em fazer uso de modelos matemáticos. É interessante, portanto, que os modelos existentes sejam intensivamente testados em sistemas reais para que se possam estabelecer diretrizes para a sua utilização, bem como uma maior confiança no seu emprego. O presente trabalho de pesquisa visou o estudo de aplicação de um modelo especialmente construído para a calibração de sistemas, através do qual é possível identificar variáveis de campo tais como rugosidades, diâmetros, parâmetros do modelo de vazamentos, etc. O modelo empregado é abrangente o suficiente para incorporar vazamentos e demandas variáveis com a pressão. Através dele, foram realizados dois estudos de caso e discutidas as razões pelas quais discrepâncias entre os valores simulados e observados foram detectadas, apesar da consistência das respostas produzidas via simulação. Algumas recomendações são feitas também no sentido de viabilizar estudos dessa natureza que possam produzir ferramental diretamente utilizável pelas concessionárias de água para abastecimento. / Considering the need for more effective control of water supply distribution systems, the calibration constitutes fundamental step to guarantee that the system behavior under several operational conditions can be reproduced. Instead of the importance of calibration and the variety of models built by the academy for this purpose, this practice has not been broadly used by the water industry, which demonstrates certain reluctance regards the use of mathematical models. It is interesting, hence, that existing models are intensively tested in real systems to establish guidelines and consequent confidence in their use. The present research focused on the study of a model especially built for the calibration of water supply systems, through which it is possible identify field variables such as roughness, diameters, parameters of leakage model, etc. The model is comprehensive enough to incorporate leakage and pressure driven demands. Two study cases were analyzed supported by the model and discussed the reasons by which disagreement between simulated and observed data were verified, instead of the consistency of results produced by simulation. Some recommendations are made to become practical this kind of study as useful tool for the water industry.

Os avanços observados em Sistemas de Distribuição de Água vêm surgindo da necessidade de aumentar a eficiência, a qualidade e segurança do abastecimento de água aos consumidores. Dois desses avanços recentes que podem ser citados são a setorização e a quantificação da confiabilidade. O processo de setorização de um sistema de distribuição de água favorece a sua gestão, uma vez que possibilita maior controle da vazão distribuída e dos limites de fornecimento do serviço, entretanto pode implicar em restrições no abastecimento durante eventos de falhas ou emergências, sendo necessária a avaliação da confiabilidade. Diversos pesquisadores têm buscado uma metodologia coerente e adequada para quantificar a confiabilidade em sistemas de distribuição de água, muitos deles desenvolvendo métricas alternativas que visam simplificar esta definição. O presente trabalho visou investigar métricas alternativas de confiabilidade, propostas na literatura especializada, aplicando-as a estudos de caso para a rede original e após a setorização. Os resultados sugerem a viabilidade de utilização das métricas de confiabilidade como forma de avaliar diferentes níveis de setorização, no que diz respeito à vulnerabilidade do sistema. / Improvements upon Water Distribution Systems have been made under the urge of increasing efficiency, quality and security of water supply to its customers. A couple of recent breakthroughs on Water Distribution Network are partitioning and reliability. Water network partitioning enhances operational management, once it enables higher control of supplied flow and awareness of boundaries regarding each partition. Nevertheless, it can lead to supply restrictions under emergency and failure events, what may require reliability assessment. Several researchers have pursued consistent approach to quantify reliability of Water Distribution Network, many of them proposed surrogate measures which focused on simplifying its measurement. The aim of this work is to look into surrogate reliability measures proposed in the literature and applying them on case studies for its original layout and after proposed partitioning. The results implies the usage feasibility for the reliability measures as a way of evaluating different stages of partitioning, regarding system\'s vulnerability.

O trabalho apresenta uma proposta de metodologia para diagnóstico de sistemas de distribuição de água através da elaboração, passo a passo, e de uso de simuladores hidráulicos apoiados por aplicativos de geoprocessamento. Utilizando-se de dados reais como o histórico operacional de vazamentos dentro da região adotada num intervalo de tempo, espera-se fornecer ao analista um instrumento de análise visual do comportamento hidráulico do setor em função de uma escala progressiva de ocorrências, mapeada através de cores, permitindo avaliar a qualidade do modelo hidráulico como um todo, corrigindo desvios para que o mesmo reproduza eficientemente o comportamento real da rede de distribuição. Através deste, esperase avaliar as consequências da variação das pressões e vazões durante o dia, subsidiando tomadas de decisão, permitindo avaliação das opções e a redução de riscos e investimentos desnecessários. / The work presents a proposed methodology for diagnosis of water distribution systems through the development, step-by-step and hydraulic simulators use supported by geoprocessing applications. Using real data and operational history of leaks within the region adopted a time interval, is expected to provide the analyst a tool for visual analysis of the hydraulic behavior of the sector according to a progressive scale of occurrences, mapped through colors, in order to evaluate the quality of hydraulic model as a whole, correcting deviations so that it efficiently reproduces the actual behavior of the distribution network. Through this, it is expected to evaluate the consequences of variation of pressure and flows during the day, supporting decision-making, allowing the evaluation of the options and the reduction of unnecessary risks and investments.

Thesis (M.Dev.) --University of Limpopo, 2010 / The aim of the research study was to examine and analyse the main constraints faced by the Polokwane Local Municipality in delivery water services to Mabokelele Village. For the researcher to be able to achieve the aim of the study, key research questions were posed which enabled the researcher to gather / collect data that helped shed more light in the research project. Research questions such as what are the constraints faced by the Polokwane Local Municipality in water delivery services, and what strategies are been to address those constraints and how effective are those strategies, were posed to the participants of this research study. The study used the qualitative research design. Respondents were seen as experts of their own life situation. Face to face interviews were used to collect data from the participants. Data analyses was done in the form of content data analysis. The key findings of the research project:- Shortage of skills in financial management, inadequate water service infrastructure, inadequate human resource for water service delivery, lack of co-operation between the Polokwane Municipality and the Mabokelele Induna and lack of community participation and consultation by the Polokwane Local Municipality and long delays caused by the tendering process were identified as the key findings for the study. Recommendations for the study was guided by the findings of the research project. The following served as recommendations for the study : Polokwane Local Municipality should ensure that people with financial management skills and project management are employed to avoid under-spending of the budget. Community participation and consultation should be key when implementing projects to the community, Department of Water Affairs to ensure that enough water service infrastructure is provided so that the Municipality can function properly. Dwarf should speed up the transfer of officials to Polokwane Local Municipality and lastly, the red tapes in the tendering processes should be minimized to avoid long delays in the approval of water projects.

An ideal drinking water distribution system (DWDS) must supply safe drinking water with free chlorine residual (FCR) in the form of HOCI and OCIֿ at a required concentration level. Meanwhile the FCR is consumed in the bulk liquid phase and at the DWDS pipes wall as the result of chemical reactions. Because of these, an optimized chlorine dosing for the DWDS using model-based predictive control (MBPC) is developed through the steps of modelling the FCR transport along the main pipes of the DWDS, designing chlorine dosing and implementing a multiple-input multiple-output system control scheme in Matlab 7.0.1 software. Discrete time-space models (DTSM) that can be used to predict free chlorine residual (FCR) concentration along the pipes of the DWDS over time is developed using explicit finite difference method (EFDM). Simulations of the DTSM using step and rectangular pulse input show that the effect of water flow rate velocity is much stronger than the effect of chlorine effective diffusivity coefficient on the FCR distribution and decay process in the DWDS main pipes. Therefore, the FCR axial diffusion in single pipes of the DWDS can be neglected. Investigating the effect of injection time, initial chlorine distribution, and overall chlorine decay rate constant involved in the process have provided a thorough understanding of chlorination and the effectiveness of all the parameters. This study proposed a model-based chlorine dosing design (MBCDD) based on a conventional-optimum design process (CODP) (Aurora, 2004), which is created for uncertain water demand based on the DTSM simulation. / In the MBCDD, the constraints must be met by designing distances between chlorine boosters and optimal value of the initial chlorine distribution in order to maintain the controlled variable (CV), i.e. FCR concentration with a certain degree of robustness to the variations of water flow rate. The MBCDD can cope with the simulated DWDS (SDWDS) with the conditions; the main pipe is 12 inch diameter size with the pipe length of 8.5 km, the first consumers taking the water from the point of 0.83 km, the assumed pipe wall chlorine decay rate constant of 0.45 m/day, and the value of chlorine overall decay rate constants follow Rosman's model (1994), by proposing a set of rules for selecting the locations for additional chlorine dosing boosters, and setting the optimal chlorine dosing concentrations for each booster in order to maintain a relatively even FCR distribution along the DWDS, which is robust against volumetric water supply velocity (VWS) variations. An example shows that by implementing this strategy, MBCDD can control the FCR along the 8.5 km main pipe of 12 inch diameter size with the VWS velocity from 0.2457 to 2.457 km/hr and with the assumed wall and bulk decay constants of 0.45 and 0.55 m/day, respectively. An adaptive chlorine dosing design (ACDD) as another CODP of chlorine dosing which has the same concept with the MBCDD without the rule of critical velocity is also proposed in this study. The ACDD objective is to obtain the optimum value of initial chlorine distribution for every single change in the VWS. Simulation of the ACDD on the SDWDS shows that the ACDD can maintain the FCR concentration within the required limit of 0.2-0.6 mg/1. / To enable water quality modelling for studying the effectiveness of chlorine dosing and injection in the form of mass flow rate of pure gaseous chlorine as manipulated variable (MV), a multiple-input multiple-output (MIMO) system is developed in Simulink for Matlab 7.0.1 software by considering the disturbances of temperature and circuiting flow. The MIMO system can be used to design booster locations and distribution along a main pipe of the DWDS, to monitor the FCR concentration at the point just before injection (mixing) and between two boosters, and to implement feedback and open-loop control. This study also proposed a decentralized model-based control (DMBC) based on the MBCDD-ACDD and centralized model predictive control (CMPC) in order to optimize MV to control the CV along the main pipe of the DWDS in the MIMO system from the FCR concentration at just after the chlorine injection (CVin) to the FCR concentration (CVo) before the next chlorine injection with the constraints of 0.2-0.6 ppm for both the CVin and CVo. A comparison of the performances of decentralized PI (DPI) control, DMBC and CMPC, shows that the performances of the DMBC and CMPC in controlling the MIMO system are almost the same, and they both are significantly better than the DPI control performance. In brief, model-based predictive control (MBPC), in this case a decentralized model-based control (DMBC) and a centralized predictive control (CMPC), enable optimization of chlorine dosing for the DWDS.

Implementation of physically distributed catchment modelling systems reshapes the fundamental philosophy of traditional calibration approaches by supporting the concept of equifinality. Arising from the concept of equifinality, alternative behavioural parameter sets within a given catchment modelling system structure can generate similar levels of simulation performance. This concept is motivated by the existence of a variety of uncertainties associated with a complex catchment modelling system, such as an imperfect model structure, measurement errors in both the input data and the recorded flows, and unknown, or poorly defined, interactions among parameters. However, the difficulty of searching for behavioural parameter sets increases as the complexity of the catchment modelling systems increases. This study undertook an investigation on the feasibility and robustness of a real-value coding genetic algorithm (GA) for calibrating the physically distributed Storm Water Management Model (SWMM) using the Centennial Park catchment in Sydney as a case study. It was found that a real-value coding GA was a robust technique suitable to search for behavioural parameter sets and, in particular, it was found that this approach was capable of identifying the promising range of values for spatially variable parameters. Moreover, the widespread use of physically distributed catchment modelling systems has highlighted the importance of estimating the uncertainty in the parameter values and in the predictions obtained from a complex catchment modelling system as well as in catchment averaged, or lumped, systems that have been the focus of many previous studies. Bayesian inference has been shown to be a tool suitable for parameter uncertainty estimation in catchment modelling. However, the application of Bayesian inference faces difficulties in complex high-dimensional systems where there is little if any a priori knowledge about the proposal distribution of the parameters. In this study, a real-value coding GA was used to undertake uncertainty estimation on spatially variable control parameters with little a priori knowledge about the proposal distribution of parameters. After 50,000 evaluations, the marginal posterior distributions of spatially variable parameters which are associated with behavioural parameter sets were identified. The performance of a behavioural parameter set under a range of hydrological conditions was evaluated. Updating of the marginal distributions of these control parameters was implemented by adding additional calibration data. Interactions among the spatially variable control parameters were investigated also. Results based on the Pearson Correlation method indicate no clear relationship between any two control parameters. However, a methodology to detect relationships among groups of parameters was developed. Application of this methodology suggests that the simulation performance of SWMM was influenced by combinations of parameter values rather than values of the individual parameters. Finally, the predictive uncertainty associated with the existence of behavioural parameter sets was considered. A number of alternative strategies were used to evaluate the predictive performance. Consideration of the results suggests that use of a small number of parameter sets randomly selected from the large number of behavioural parameter sets was the best strategy in terms of efficiently obtaining predictive performance.

This dissertation examines the interdependence between urban water distribution systems and urban fire response. The focus on interdependent critical infrastructures is driven by concern for security of water systems and the effects on related infrastructures if water distribution systems are damaged by terrorist attack or natural disaster. A model of interdependent infrastructures (principally water distribution systems and fire response) is developed called the Model of Urban Fire Spread (MUFS). The model includes the capacity to simulate firefighting water demands in a community water system hydraulic model, building-to-building urban fire spread, and suppression activities. MUFS is an improvement over previous similar models because it allows simulation of urban fires at the level of individual buildings and it permits simulation of interdependent infrastructures working in concert. MUFS is used to simulate a series of multi-mode attacks and failures (MMAFs) – events which disable the water distribution system and simultaneously ignite an urban fire. The consequences of MMAF scenarios are analyzed to determine the most serious modes of infrastructure failure and urban fire ignition. Various methods to determine worst-case configurations of urban fire ignition points are also examined. These MMAF scenarios are used to inform the design of potential mitigation measures to decrease the consequences of the urban fire. The effectiveness of mitigation methods is determined using the MUFS simulation tool. Novel metrics are developed to quantify the effectiveness of the mitigation methods from the time-series development of their consequences. A cost-benefit analysis of the various mitigation measures is conducted to provide additional insight into the methods’ effectiveness and better inform the decision-making process of selecting mitigation methods. Planned future work includes further refinement of the representation of fire propagation and suppression in MUFS and investigation of historical MMAF events to validate simulation predictions. Future efforts will continue development of appropriate optimization methods for determining worst-case MMAF scenarios. This work should be of interest to water utility managers and emergency planners, who can adapt the methodology to analyze their communities’ vulnerability to MMAFs and design mitigation techniques to meet their unique needs, as well as to researchers interested in infrastructure modeling and disaster simulation.