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Numerical hydraulic modeling of urban waste water collecting systems : Working Project at Chazelles-sur-Lyon, FranceGenty, Stanislas January 2014 (has links)
Urban waste water collecting systems are designed to convey domestic, industrial and storm water. When sizing sewer network, heavy rainfall must be considered to provide the needed hydraulic capacity for collection. Maintenance is also required in order to avoid anomalies such as inflow, infiltration and unusual polluted discharges from Combined Sewer Overflows (CSOs). Inflow and infiltration decrease the treatment yield at the Waste water Treatment Plant (WWTP) and participate in hydraulic overloads and overflows. CSOs have a direct impact on the pollution of water bodies and must be strictly sized and monitored. Detecting sizing and maintenance anomalies is crucial to ensure public health and a good status of our natural environment. Today, numerical hydraulic models support consulting engineers in assessing overflows then in choosing the best technical and cost-effective scenario. The objectives of this paper are to review the dysfunctions of collecting system and to understand how a numerical hydraulic model is constructed, calibrated and then used to establish a Corrective Action Plan (CAP). My master thesis is based on a working project achieved at SAFEGE (Group SUEZ Environnement) in the Urban Hydraulics Department in Lyon (Rhône-Alpes, France) between September 2013 and February 2014. The paper will present some outcomes obtained from an Urban Hydraulic Project at Chazelles-sur-Lyon (Rhône-Alpes, France) in the South West of Lyon. Mike Urban is the software - developed by the company DHI Water- used for the numerical hydraulic modeling.
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Refining and Expanding the Feature Stamping ProcessEmery, Russell N. 24 August 2005 (has links) (PDF)
The accuracy of numerical models analyzing hydrologic and hydraulic processes depends largely on how well the input terrain data represents the earth's surface. Modelers obtain terrain data for a study area by performing surveys or by gathering historical survey data. If a modeler desires to create a predictive model to simulate the addition of man-made features such as channels, embankments and pits, he must modify the terrain data to include these features. Doing this by hand is tedious and time consuming. In 2001 Christensen implemented a tool in the Surface-water Modeling System (SMS) software package for integrating man-made geometric features into surveyed terrain data. He called this process feature stamping. While Christensen's feature stamping algorithms decrease the time and effort required to integrate geometric features into existing terrain data, they only function on centerline-based features having a constant trapezoidal cross-section. In addition to placing geometric limitations on the features they stamp, Christensen's feature stamping algorithms also possess several instabilities. These instabilities arise when stamping features that leave the bounds of the terrain data, and when modifying and re-stamping features that have already been stamped. This thesis presents changes and enhancements made to Christensen's feature stamping algorithms. These changes and enhancements completely eliminate the instabilities found in Christensen's feature stamping algorithms and make it possible for numerical modelers to stamp more complex geometric features having compound slopes, asymmetric cross-sections and varying cross-sections along their length. Finally, additional feature stamping algorithms make it possible to stamp radial features such as mounds and pits.
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Assessment of hydropower mitigation measures for fish habitat rehabilitation with a coupled eco-hydraulic model : A case study on the Skålan-Äldern stretch / Bedömning av vattenkraft åtgärder för rehabilitering av livsmiljöer för fisk genom ekohydraulisk modellering : En fallstudie av Skålan-Äldern sträckanPolato, Francesca January 2021 (has links)
In the past century, hydropower development in Sweden has been facilitated by the lack of appropriate environmental legislation. This exploitation has resulted in the current poor ecological status of most Swedish water bodies affected by hydropower, and in the need for new policies that reflect the 2000 European Water Framework Directive. Thus, the Swedish Agency for Marine and Water management (SwAM), the Swedish Energy Agency (SEA) and Svenska Kraftnät have elaborated a new national plan for the revision of almost all hydropower licenses in the next 20 years, and Vattenkraftens Miljöfond has carried out a pilot project on Ljungan river, to test different working methods for regional collaboration, and to find effective solutions for achieving the greatest possible benefit for the aquatic environment, while ensuring an efficient national hydropower supply. This thesis focuses on the fish habitat rehabilitation of a portion of Ljungan river highly affected by hydropower practices. By combining a 1D/2D hydraulic model, calibrated and validated, with a habitat model that defines the hydraulic preferences of the target fish species, it was possible to run different simulations and to quantify the optimal habitat obtainable in each scenario, following the PHABSIM methodology. The outputs of this analysis were produced in the form of Composite Suitability Index (CSI) maps and Weighted Usable Area (WUA)discharge curves. The former resulted to be a very useful tool for analyzing the spatial distribution of suitable habitats for certain ecological processes, and for planning instream habitat improvement measures, while the latter have been efficiently used to identify and quantify the maximum habitat improvement achievable with the different mitigation scenarios. This approach helped to firstly assess the habitat improvement that would result from removing the weirs located along the river, leading to the conclusion that the removal would be effective only if combined with other morphological changes of the river channel. Additionally, the coupled ecohydraulic model has been useful for the design of ecological flow scenarios able to achieve different levels of habitat improvement, including scenarios aimed at minimizing energy production losses. The use of the PHABSIM methodology resulted to be very suitable for the scale and scope of the project. However, it also required to limit the iii ecological drivers considered in the analysis and to make some simplistic assumptions about target species behavior, which must always be underlined and acknowledged when using the results in decisionmaking processes. / Under det senaste århundradet har vattenkraftsutbyggnaden i Sverige underlättats av bristen på lämplig miljölagstiftning. Detta utnyttjande har lett till att de flesta svenska vattenförekomster har en dålig ekologisk status och att det behövs en ny politik som återspeglar det europeiska ramdirektivet för vatten från 2000. Således har Havs och vattenmyndigheten, Energimyndigheten och Svenska Kraftnät utarbetat en ny nationell plan för översyn av nästan alla vattenkraftslicenser under de kommande 20 åren, och Vattenkraftens Miljöfond har genomfört ett pilotprojekt i Ljungan älv för att testa olika arbetsmetoder för regionalt samarbete och hitta effektiva lösningar för att uppnå största möjliga nytta för vattenmiljön samtidigt som man säkerställer en effektiv nationell vattenkraftförsörjning. Denna avhandling fokuserar på återställandet av fiskhabitatet i en del av Ljungan älven som är starkt påverkad av vattenkraftsutövning. Genom att kombinera en 1D/2D hydraulisk modell, kalibrerad och validerad, med en habitatmodell som definierar målfiskarternas hydrauliska preferenser var det möjligt att göra olika simuleringar och kvantifiera den optimala livsmiljö som kan erhållas i varje scenario, enligt PHABSIMmetodiken. Detta tillvägagångssätt har använts för att först och främst bedöma den förbättring av livsmiljön som skulle bli resultatet av att ta bort de dammar som finns längs älvsträckan, vilket ledde till slutsatsen att avlägsnandet skulle vara effektivt endast om det kombineras med andra morfologiska förändringar av flodfåran. Dessutom har den kopplade ekohydrauliska modellen varit användbar för att utform ekologiska flödesscenarier som kan uppnå olika nivåer av habitatförbättring, inklusive scenarier som syftar till att minimera förlusterna i energiproduktionen.
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Modèle d'aide à la conduite de réseaux de froid / Decision-support model for district cooling operationCasetta, Damien 27 October 2017 (has links)
La maîtrise de la demande en climatisation des bâtiments tertiaires peut contribuer à la limitation du réchauffement climatique à 2°C. Les réseaux de froid urbain sont une solution pour répondre à cette demande avec une haute efficacité énergétique. Une conduite performante est cependant essentielle pour maintenir et augmenter leurs avantages compétitifs. L'objectif de la thèse est de contribuer à la construction d'un outil d'aide à la conduite journalière des réseaux de froid. La difficulté réside à deux niveaux : la diversité des décisions et la complexité des phénomènes physiques sous-jacents. L'originalité est de proposer une méthodologie pour aider au pilotage des groupes frigorifiques, des tours aéroréfrigérantes, de la pression différentielle et de la répartition de puissance entre des centrales de production aux performances variables. La méthodologie développée est appliquée au réseau de froid de Paris-Bercy exploité par Climespace. Tout d'abord, un modèle intégrant une représentation physique des centrales de production, du réseau de distribution et des sous-stations, est développé. En particulier, un modèle de type semi-empirique, paramétrable sur des mesures, est modifié pour calculer les performances non-nominales des groupes frigorifiques centrifuges. La validation du modèle complet est réalisée sur un jeu de données indépendant de l'identification. Ensuite, le modèle est exploité pour rechercher une conduite optimisée à partir d'un modèle de prévision de la demande. La méthode proposée est séquentielle : résolution a priori des optimisations locales puis génération de modèles quadratiques de centrales servant à déterminer la répartition optimale. La pression différentielle est minimisée à partir de l'identification, par simulation, de la sous-station défavorisée. Enfin, la réduction de la consommation électrique est évaluée sur une semaine d'été. / Cooling demand management of commercial buildings can contribute to limit global warming below 2°C. District cooling is an energy-efficient option. However, improving operational performance is of great importance to ensure and increase its competitive advantages. The aim of this thesis is to contribute to the development of a decision-support tool for daily operation of district cooling networks. Challenges lie at two levels: diversity of decisions to be taken and complexity of physical phenomena involved. The original aspect of our work is to propose a methodology to improve chillers and cooling towers control, differential pressure management and dispatching between production plants with variable efficiency. Our developments are applied to the district cooling of Paris-Bercy, operated by Climespace. First; a model featuring a physical description of chilled-water production plants, distribution network and buildings substations, is developed. In particular, a semi-empirical model with identified parameters is modified to compute non-nominal characteristics of centrifugal chillers. The system model is validated against an independent dataset. Then, the model is used to find optimized controls from cooling loads forecast. The proposed methodology is sequential: pre-computation of optimal set-points at plant level and then generation of quadratic plant models to solve the dispatching optimization problem at each time step. Differential pressure is minimized with a simulation-based tracking of the critical substation. To conclude, electricity consumption reduction with optimized controls is evaluated during a summer week.
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Studies On Application Of Control Systems For Urban Water NetworksKumar, M Prasanna 05 1900 (has links)
Management and supply of water in an urban water distribution system is a complex process, which include various complexities like pressure variations across the network depending on topography, demand variations depending on customers’ requirement and unaccounted water etc. Applying automatic control methods to water distribution systems is a way to improve the management of water distribution. There have been some attempts in recent years to develop optimal control algorithms to assist in the operation of complex water distribution systems. The difficulties involved by these hydraulic systems such as non-linearity, and diurnal demand patterns make the choice of a suitable automatic control method a challenge. For this purpose, this study intends to investigate the applicability of different controllers which would be able to meet the targets as quickly as possible and without creating undue transients.
As a first step towards application of different controllers, PD and PID linear controllers have been designed for pump control and valve control in water distribution systems. Then a Dynamic Inversion based nonlinear controller has been designed by considering the non-linearities in the system. Here, different cases considering the effects of initial conditions used, linearization methods used, time step used for integration and selection of gains etc., have been studied before arriving at best controller. These controllers have been designed for both the flow control problems and level control problems. It is found that Dynamic Inversion-based nonlinear controller outperforms other controllers.
It is well known that the performance of controllers is much dependent on the tuning of the gains (parameters). Thus in this study various alternative techniques such as Ziegler--Nichols rules (ZNPID), Genetic algorithms (GAPID) and fuzzy algorithms (FZPID) have been studied and a comparative study has been made Although with all the three gain tuning methods, required states have reached their target values, but the responses vary much in reaching to final targets. The self-tuned FZPID controller outperforms other two controllers, especially with regard to overshoots and the time taken to tune the gains for each problem.
Further, an optimal DI controller is developed for the over determined case with more controls and less targets. Energy loss is considered as an objective function and normal DI controller equations are considered as constraints. Hence, an attempt is made to reduce the energy minimization in water distribution system by formulating an optimal control problem using optimal Dynamic Inversion concept.
Finally, leakage reduction model is developed based on excessive pressure minimization problem by locating valves optimally as well as by setting valves optimally. For this purpose, optimization problem is solved using Pattern search algorithms and hydraulic analysis is carried out using EPANET program.
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Development And Control Of Urban Water Network ModelsRai, Pawan Kumar 12 1900 (has links) (PDF)
Water distribution systems convey drinking water from treatment plant and make available to consumers’ taps. It consists of essential components like pipes, valves, pumps, tanks and reservoirs etc. The main concern in the working of a water distribution system is to assure customer demands under a choice of quantity and quality throughout the complete life span for the probable loading situations. However, in some cases, the existing infrastructure may not be adequate to meet the customer’s requirements. In such cases, system modeling plays an important role in proper management of water supply systems. In present scenario, modeling plays a significant task in appropriate execution of water distribution system.
From the angle of taking management decisions valve throttling control and pumps speed control are very important. These operational problems can be addressed by manual control or by automatic control. The problem is the use of manual controls that slow down the effectiveness of the system. It reduces the efficiency of operation of valve or pump. To improve the efficiency of such water distribution systems, an automatic control based technology has been developed that links the operation of the variable speed pump control or valve throttling control. By employing an automatic control, the pump can adjust its speed at all times to meet the actual flow requirements of each load served.
In case of real system design Simulink is the most widely used tool. Commercial software package Matlab/Simulink used for creation of WDS model. The goal was to produce a model that could numerically analyze the dynamic performance of a water distribution system. A Comparison of single platform methodology (Simulink based control) and double platform methodology (Matlab and EPANET based control) has been done. Nonlinear Dynamic Inversion (DI) Control system model is developed for WDS model in Matlab/Simulink environment. Controller gain parameters are the very important value in control prospective. If the controller gain parameters are chosen incorrectly, the controlled process input can be unstable, i.e. its output diverges, with or without oscillation Tuning is the adjustment of control parameters (gains) to the optimum values for the desired control response. There are several methods for tuning controller like manual tuning (Trial and error procedure), Ziegler-Nichols method, Output Constraint Tuning (OCT) etc.
Establishment of a pump operational policy by which all the reservoirs can be fed simultaneously to meet their requirements without creating undue transients. Tune the gain of DI controllers by different tuning methods and evaluate the best tuning method on the basis of controller performance. Development of meaningful additional objective is search of lower bound pump speed on the basis of control time or settling time. To bring the pump speeds in feasible range, application of constraint in pumps speed is introduced. The magnitude of constraints can be found using Monte Carlo methods. Monte Carlo methods are frequently used in simulating physical and mathematical systems. This method may be the most commonly applied statistical method in engineering and science disciplines. Another benefit is providing increased confidence that a model is robust using Monte Carlo testing.
Model development for generalized control system for water distribution network provides the simplification needed for the simulation of large systems. Model development is based on the study of symmetric and non symmetric small, irregular networks, as well as large, regular and open bifurcating water distribution system. The problem considered in this section is that of flow dynamics in simple to complex, regular network which bifurcates in the form of a branching tree. In addition the control application of the flow network is investigated using valves as the manipulated variables to control branch flow rates. Communication between the network hydraulics coming from EPANET and control algorithm develop on Matlab (Programming Language) can be generalized with the help of development of general purpose control algorithm model.
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Analys av osäkerheter vid hydraulisk modellering av torrfåror / Analysis of uncertainties for hydraulic modelling of dry river stretchesEne, Simon January 2021 (has links)
Hydraulisk modellering är ett viktigt verktyg vid utvärdering av lämpliga åtgärder för torrfåror. Modelleringen påverkas dock alltid av osäkerheter och om dessa är stora kan en modells simuleringsresultat bli opålitligt. Det kan därför vara viktigt att presentera dess simuleringsresultat tillsammans med osäkerheter. Denna studie utreder olika typer av osäkerheter som kan påverka hydrauliska modellers simuleringsresultat. Dessutom utförs känslighetsanalyser där en andel av osäkerheten i simuleringsresultatet tillskrivs de olika inmatningsvariablerna som beaktas. De parametrar som ingår i analysen är upplösningen i använd terrängmodell, upplösning i den hydrauliska modellens beräkningsnät, inflöde till modellen och råheten genom Mannings tal. Studieobjektet som behandlades i denna studie var en torrfåra som ligger nedströms Sandforsdammen i Skellefteälven och programvaran TELEMAC-MASCARET nyttjades för samtliga hydrauliska simuleringar i denna studie. För att analysera osäkerheter kopplade till upplösning i en terrängmodell och ett beräkningsnät användes ett kvalitativt tillvägagångsätt. Ett antal simuleringar utfördes där alla parametrar förutom de kopplade till upplösning fixerades. Simuleringsresultaten illustrerades sedan genom profil, sektioner, enskilda raster och raster som visade differensen mellan olika simuleringar. Resultaten för analysen visade att en låg upplösning i terrängmodeller och beräkningsnät kan medföra osäkerheter lokalt där det är högre vattenhastigheter och där det finns stor variation i geometrin. Några signifikanta effekter kunde dock inte skönjas på större skala. Separat gjordes kvantitativa osäkerhets- och känslighetsanalyser för vattendjup och vattenhastighet i torrfåran. Inmatningsparametrarna inflöde till modellen och råhet genom Mannings tal ansågs medföra störst påverkan och övriga parametrar fixerades således. Genom script skapade i programmeringsspråket Python tillsammans med biblioteket OpenTURNS upprättades ett stort urval av möjliga kombinationer för storlek på inflöde och Mannings tal. Alla kombinationer som skapades antogs till fullo täcka upp för den totala osäkerheten i inmatningsparametrarna. Genom att använda urvalet för simulering kunde osäkerheten i simuleringsresultaten också beskrivas. Osäkerhetsanalyser utfördes både genom klassisk beräkning av statistiska moment och genom Polynomial Chaos Expansion. En känslighetsanalys följde sedan där Polynomial Chaos Expansion användes för att beräkna Sobols känslighetsindex för inflödet och Mannings tal i varje kontrollpunkt. Den kvantitativa osäkerhetsanalysen visade att det fanns relativt stora osäkerheter för både vattendjupet och vattenhastighet vid behandlat studieobjekt. Flödet bidrog med störst påverkan på osäkerheten medan Mannings tals påverkan var insignifikant i jämförelse, bortsett från ett område i modellen där dess påverkan ökade markant. / Hydraulic modelling is an important tool when measures for dry river stretches are assessed. The modelling is however always affected by uncertainties and if these are big the simulation results from the models could become unreliable. It may therefore be important to present its simulation results together with the uncertainties. This study addresses various types of uncertainties that may affect the simulation results from hydraulic models. In addition, sensitivity analysis is conducted where a proportion of the uncertainty in the simulation result is attributed to the various input variables that are included. The parameters included in the analysis are terrain model resolution, hydraulic model mesh resolution, inflow to the model and Manning’s roughness coefficient. The object studied in this paper was a dry river stretch located downstream of Sandforsdammen in the river of Skellefteälven, Sweden. The software TELEMAC-MASCARET was used to perform all hydraulic simulations for this thesis. To analyze the uncertainties related to the resolution for the terrain model and the mesh a qualitative approach was used. Several simulations were run where all parameters except those linked to the resolution were fixed. The simulation results were illustrated through individual rasters, profiles, sections and rasters that showed the differences between different simulations. The results of the analysis showed that a low resolution for terrain models and meshes can lead to uncertainties locally where there are higher water velocities and where there are big variations in the geometry. However, no significant effects could be discerned on a larger scale. Separately, quantitative uncertainty and sensitivity analyzes were performed for the simulation results, water depth and water velocity for the dry river stretch. The input parameters that were assumed to have the biggest impact were the inflow to the model and Manning's roughness coefficient. Other model input parameters were fixed. Through scripts created in the programming language Python together with the library OpenTURNS, a large sample of possible combinations for the size of inflow and Manning's roughness coefficient was created. All combinations were assumed to fully cover the uncertainty of the input parameters. After using the sample for simulation, the uncertainty of the simulation results could also be described. Uncertainty analyses were conducted through both classical calculation of statistical moments and through Polynomial Chaos Expansion. A sensitivity analysis was then conducted through Polynomial Chaos Expansion where Sobol's sensitivity indices were calculated for the inflow and Manning's M at each control point. The analysis showed that there were relatively large uncertainties for both the water depth and the water velocity. The inflow had the greatest impact on the uncertainties while Manning's M was insignificant in comparison, apart from one area in the model where its impact increased.
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Modélisation des inondations en tunnel en cas de crue de la Seine pour le Plan de Protection des Risques Inondations de la RATP (PPRI) / Modeling of tunnel flooding in the event of Seine floods for the the RATP Flood Risk Protection Plan (PPRI)Bouchenafa, Walid 03 February 2017 (has links)
La crue de 1910 de la Seine a eu une incidence directe sur le fonctionnement des différents réseaux (réseau électrique, assainissement des eaux usées, transport, eau potable). Le réseau RATP a été particulièrement atteint dans son fonctionnement. Les dommages qu’une crue centennale pourrait engendrer aujourd’hui risquent d’être plus importants encore car le réseau actuel est plus vulnérable du fait des nombreux équipements électriques et informatiques qu’il comporte. La majorité des émergences (les entrées d’eau) de la RATP est située en zone inondable. Lors d’une crue majeure de la Seine, les écoulements dus aux inondations se propagent directement dans la partie souterraine et centrale du réseau (Métro et RER) par le biais de ces émergences. Cette thèse s'intéresse à la simulation hydrodynamique des écoulements dans le réseau RATP en utilisant le logiciel MIKE URBAN dédié à la modélisation des réseaux d’assainissement. Cette modélisation nécessite une bonne connaissance de l’origine des écoulements pour mieux les prendre en compte. En effet, le réseau RATP est inondé par les eaux superficielles et les eaux d’infiltration. Afin de mieux quantifier les volumes entrants dans le réseau, un modèle physique d’une bouche de métro type a été réalisé. Les résultats des essais physiques ont permis de valider un modèle numérique qui caractérise les écoulements autour d’une bouche de métro et quantifie les volumes entrants. Cela a permis également de proposer une formule théorique de débit tenant compte de la géométrie d’une bouche de métro. Les écoulements par infiltration sont quant à eux modélisés en fonction de la charge de la nappe et validés avec des mesures in situ. Ce travail de recherche a comme objectif d’améliorer et valider un modèle de simulation. Il s’agit de mettre en œuvre un outil opérationnel d’aide à la décision qui permettra à la cellule inondation de la RATP de bien comprendre le fonctionnement de son réseau afin d’améliorer son plan de protection contre le risque inondation. / The 1910 flood of the Seine had a direct impact on the functioning of the different networks (Electricity network, sewerage, transport, water distribution). The RATP network was particularly affected in its functioning. The damage that centennial flood could cause today may be even greater because the current network is more vulnerable because of the numerous electrical and computer equipment that it comprises. The majority of the emergences (The water ingress) of the RATP is located in flood areas. During a major flooding of the Seine, the flows due to the floods propagate directly into the underground and central part of the network (Metro and RER) through these emergences. This thesis is interested in a hydrodynamic simulation by MIKE URBAN, Model used to model the RATP network due to its MOUSE engine developed by DHI for the sewerage networks. This work also presents the results obtained on a physical model of a subway station. The experimental data were used to model water ingress within the RATP network from the subway station. Network protection against infiltration requires a thorough knowledge of underground flow conditions. Infiltrations through the tunnels are estimated numerically. The aim of this research is to improve and validate a simulation model. It is a question of implementing an operational decision support tool which will allow the flood cell of the RATP to understand the functioning of its network in order to improve its flood risk protection plan.
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Modeling and Analysis of Water Distribution SystemsManohar, Usha January 2014 (has links) (PDF)
In most of the urban cities of developing countries piped water supply is intermittent and they receive water on alternate days for about few hours. The Unaccounted For Water (UFW) in these cities is very high due to aged infrastructure, poor management and operation of the system. In the cities of developing countries, supplied water is not able to meet the demand and there is huge gap between supply and demand of water. To meet the water demand people are depending on other sources of water like groundwater, rain water harvesting, waste water treatment, desalination etc. Huge quantity of groundwater is extracted without any account for the quantity of water used. The main challenge for water authorities is to meet the consumer demands at varying loading conditions. However, the present execution of decisions in the operational management of WDS is through manual control. The manual control of valve throttling and control of pump speed, reduces the efficiency and operation of WDS. In such cases, system modeling coupled with automated control can play a significant role in the appropriate execution and operation of the system. In the past few decades, there has been a major development in the field of modeling and analysing water distribution systems. Most of the people in Indian mega cities are facing water problems as they are not able to receive safe reliable drinking water. In rapidly growing cities, the water resources management has been a major concern for the Government. There is always a need to optimize the available water resources when the rate of demand constantly beats the rate of replenishments.
Mathematical modeling of WDS has become an indispensible tool since the ages to model any type of WDS. Development of mathematical models of WDS is necessary to analyse the system behavior for a wide range of operating conditions. Using models, problems can be anticipated in proposed or existing systems, and solutions can be evaluated before time, money, and materials are invested in a real-world project.
In the present study, we have developed a model of WDS of a typical city like Bangalore, India and analysed them for several scenarios and operating conditions. Bangalore WDS is modeled using EPANET. Before a network model is used for analysis purpose, it must be ensured that the model is predicting the behavior of the system with reasonable accuracy. The process of matching the parameters of the developed model and the field observed data is known as calibration. All WDS require calibration for effective modeling and simulation of the system. Demand and roughness are the most uncertain parameters and they are adjusted repeatedly to get the required head at nodes and flow in the pipes. The calibration parameters usually include pipe roughness, valve settings, pipe diameter and demand. Pipe roughness, valve settings and pipe diameter are associated with the flow conditions and the demands relate to the boundary conditions. For Bangalore WDS, the values of roughness coefficient and demand are available; and the values of valve settings are not available. Hence, this value is estimated during calibration process. Dynamic Inversion (DI) nonlinear controller with Proportional Integral Derivative (PID) features (DI-PID) is used for calibrating WDS for valve settings on the basis of observed flow and roughness coefficient. From the obtained results it is observed that, controllers are capable of achieving the target flow to all the GLRs with acceptable difference between the flow meter readings and the simulated flow. After calibrating any real WDS to the field observed data, it will be useful for water authorities if the consumer demands are met up to certain extent. This can be achieved by using the concept of equitable distribution of water to different consumers.
In the urban cities of developing countries, often large quantities of water are supplied to only a few consumers, leading to inequitable water supply. It is a well known fact that quantity of water supplied from the source is not distributed equitably among the consumers. Aged pipelines pump failures, improper management of water resources are some of the main reasons for it. Equitable water to different consumers can be provided by operating the system in an efficient manner. Most of the urban cities receive water from the source to intermediate reservoirs and from these reservoirs water is supplied to consumers. Therefore, to achieve equitable water supply, these two supply levels have to be controlled using different concepts/ techniques. The water requirement of each of the reservoirs has to be calculated, which may depend on the number of consumers and consumer category. Each reservoir should receive its share of water to satisfy its consumer demand and also there must be provision to accommodate shortages, if any. The calibrated model of Bangalore WDS is used to achieve equitable water supply quantity to different zones of Bangalore city. The city has large undulating terrain among different zones which leads to unequal distribution of water. Dynamic Inversion (DI) nonlinear controller with Proportional Integral Derivative (PID) features (DI-PID) is used for valve throttling to achieve the target flows to different zones/reservoirs of the city at different levels. Equitable water distribution to different reservoirs, when a part of the source fails to supply water is also discussed in this thesis. From the obtained results it is observed that, controllers were responding in all the cases in different levels of targets for such a huge network. When there is change in supply pattern to achieve the equitable supply of water to different zones, the hydraulics of the WDS will change. Therefore, it is necessary to understand whether the system is able to handle these changes. The concept of reliability can be used to analyse the performance of WDS for wide range of operating conditions.
Reliability analysis of a WDS for both normal and likely to occur situations will give a better quality of service to its consumers. Calculating both hydraulic and mechanical reliability is important as the chances of occurrence of both the failure scenarios are equal in a WDS. In the present study, a methodology is presented to model the nodal, system and total reliability for water supply networks by considering the hydraulic and mechanical failure scenarios. These two reliability measures together give the total reliability of the system. Analysing a real and complex WDS for the probable chances of occurrence of the failure scenarios; and then to anlyse the total reliability of the system is not reported in the literature and this analysis is carried out in the present study for Bangalore city WDS. The hydraulics of the system for all the operating conditions is analysed using EPANET. Hydraulic reliability is calculated by varying the uncertain independent parameters (demand, roughness and source water) and mechanical reliability is calculated by assuming system component failures. The system is analysed for both the reliability scenarios by considering different chances of failure that may occur in a real WDS; and hence the total reliability is calculated by making different combinations of hydraulic and mechanical failure scenarios. Sensitivity analysis for all the zones is also carried out to understand the behavior of different demand points for large fluctuation in hydraulics of the system. From the study, it is observed that, Hydraulic reliability decreases as the demand variation increases. But, as the roughness variation increases, there is no much change in the nodal or system reliability. Consumer demand or reliability of the WDS can be increased by saving the water lost in the system. This can be achieved by tracking the water parcel from the source till the consumer end, which will give an idea about the performance of different stages and zones in achieving the target flows.
Huge quantity of water is lost in WDS and hence it is necessary to account for the water lost at different levels, hence the system can be managed in a better way. In most of the intermittent water supply systems demand is controlled by supply side; there is also a need to understand the demand variation at the consumer end which in turn affects the supply. Matching this varied supply-demand gap at various levels is challenging task. To get a better control of such problem, water balance (WB) equations need to be derived at various levels. When we derive these WB equations it should be emphasized that UFW is one of the major component of this equation. Given this back ground of the complex problem, for a typical city like Bangalore, an attempt is made to derive WB equations at various levels. In the present study, stage-wise and zone-wise WB is analysed for different months based on the flow meter readings. The conceptual model developed is calibrated, validated and also the performance of the model is analysed by giving a chance of error in the flow measurement. Based on all the above observations, stage-wise and zone-wise water supply weights are also calculated. From the study it is found that, there is no much loss of water in all the four stages of supply. Water loss is minimal of about 3 % till water reaches from source to GLRs. Water is transferred between the stages during some days of the month, may be due to shortage of water or due to unexpected demand. Huge quantity of water is lost in the distribution main which is of about 40 to 45% for all the moths which is analysed. This type of model will be extremely useful for water supply managers to manage their resources more efficiently and this study is discussed in detail as a part of this thesis.
As mentioned above, huge quantity of groundwater is used in urban cities and the quantity of water extracted is not accounted. In the present study, zone wise and sub zone-wise piped water and ground water used in different parts of the cities is analysed with the help of available data. From the study it is observed that, the quantity of piped water supply and UFW is consistent for the time period analysed and the quantity of water withdrawn from the borewells are varying considerably depending on the yield of the borewlls in different zones.
The main components of urban water supply are piped water, ground water, rainfall and runoff generated, UFW, waste water produced and other water quantities which may be minute. In future, to manage the water resources properly, integrated water management is necessary in city scale which will give an idea about the total water produced and the water utilized at the consumer end. Therefore, integrated water management concept is carried out in Hebbal region, (a small part of Bangalore) using the available data. From the analysis we noticed that, domestic water supplied to North sub zones are better when comparing to East sub zones. This type of total water balance can be studied in other parts of Bangalore, to understand the behavior of different water components and to make better decisions.
The developed model, analysis and operating conditions of this study can be applied to other similar cities like Bangalore. This type of study may be useful to water authorities for better control of the resources, or in making better decisions and these types of models will act as decision support systems.
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Confección de modelos de redes de distribución de agua desde un Sig y desarrollo de herramientas de apoyo a la toma de decisionesBartolín Ayala, Hugo José 31 October 2013 (has links)
Advances in information technology in the past two decades have seen innovations in the field of domestic
and industrial computing that led to a paradigm shift in the management and operation of urban water
systems by water utility companies. The traditional public management policy that focused on ensuring a
minimum quality of service regardless of the costs associated with the processes of catchment, treatment
and distribution of water, in many cases even unknown, have evolved towards more efficient cost sensitive
models. These new wholly or partly public funded management systems improve not only the quality of
service offered to users, but also optimize resources by reducing the cost and causing the minimum
environmental impact.
The new challenges raised by the European Water Framework1 Directive by imposing cost recovery to
improve water efficiency and environmental sustainability have led to a significant change at all levels of
water management. Consequently, new priorities have been established in terms of infrastructure
management that require the reduction of water losses and the improvement of the water efficiency in
urban networks for human consumption. Likewise, in a broader context which includes the water--energy
binomial, it is also desirable to improve the energy efficiency and carbon emissions of these systems.
Today, network sectoring is the most commonly used strategy to improve management and increase network
performance. It basically consists of dividing the network into several smaller hydraulic sectors, where water
inlets and outlets are perfectly controlled. This simplifies the task of carrying out periodic water balances in
each of the sectors, and allows water loss volume to be assessed for a given period of time.
As configuring network sectors is not a trivial task, it is therefore important to have appropriate tools to
perform the task efficiently and effectively. Mathematical models can play an important role as decision
support tools to help water managers assess the performance of water network distribution systems.
This thesis aims to address the current problems of managing urban water networks by combining new
information-processing technologies with innovative network modelling techniques. It intends to facilitate the
system diagnosis and extend the use of models on the decision-making process to provide better solutions to
the management of urban water networks.
For this purpose a software extension that works on a geographic information system (GIS) has been
developed. It integrates: the hydraulic and water quality simulation program EPANET 2, innovative tools for
model analysis and diagnostic, automatic tools for sectoring and computing tools to conduct water balances
in the sectors using actual measurements.
The work demonstrates the compatibility and complementarity of GIS and hydraulic models as technologies
that can be used to support the assessment and diagnosis of water distribution networks. Considering that the
majority of information linked to the network system has some geographic reference, it is not surprising that
GIS has become a popular tool for dealing with such information. At the same time, the integration of
mathematical modelling and simulation tools, offers the GIS a new dimension in the realm of hydraulic study
of water networks. Furthermore, if this specific integration is provided with new features aimed not only to
facilitate the model building, but also to assist the user in decision-making using powerful algorithms based on
the application of the graph theory, the result is a powerful up-to-date analytical tool, which opens up new
possibilities in the field of management and efficient operation of urban water supply systems. / Bartolín Ayala, HJ. (2013). Confección de modelos de redes de distribución de agua desde un Sig y desarrollo de herramientas de apoyo a la toma de decisiones [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/33152 / TESIS
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