Large-scale Water Supply Systems Research Articles

Multilevel Partitioning with Multiple Strategies for Complex Water Distribution Network

The operation and dispatching of large-scale water supply systems is becoming more and more complex, and effective partitioning is a good response measure to this increasing complexity. This paper presents a multilevel partitioning method using freely configurable strategies suitable for multiobjective situations such as allocation of water sources, pressure regulation, and flow measurement. The method mainly relies on two strategies. Using Strategy A, water supply features are constructed based on water sources and a partition clustering is implemented that is suitable for the overall partitioning of a water supply from multiple sources. Using Strategy B, important pipes are first extracted to simplify the search path and then various constraints (pressure boundary, flow shunt, cross-river management) are used to select control points and partition by graph theory searching. This strategy is suitable for refining partitioning of the structure of a specific source. A combination of the aforementioned strategies was applied to the first-level and second-level partitioning in a case study. By flexibly configuring strategies and constraints, good partitioning is achieved and multiple management goals are accomplished satisfactorily. This research enhances understanding of the operational issues in complex water systems. The overall management of water networks can be disassembled into tasks at all levels and with their own objectives performed in stages. The solution provided in this study has the advantages of flexibility and effectiveness for a variety of complex water distribution situations, contributing insights into the real challenges of partitioning large water distribution networks.

Insights for booster chlorination strategy based on DBPs control in a large-scale water supply system

Based on a one-year field investigation of disinfection by-products (DBPs) in large scale water distribution system (LSWDS), the various characteristics of DBPs together with their correlation with booster chlorination were elaborated through ArcGIS model. Furthermore, the effects of booster chlorination on DBP formation were investigated through simulated experiments. Residual chlorine showed a strong relationship with occurrence of different DBPs in LSWDS, and the yield of DBPs increased significantly after booster chlorination. The simulated chlorination experiments showed that diminution of the ratio of primary to secondary (booster) chlorination dosage, and delaying the secondary chlorine addition reduced the generation of DBPs during water conveyance. The yield concentrations of THMs and HAAs obviously increased after booster chlorination. The correlation between HAAs and chlorine dosage is weaker in the field research than in the simulation experiment while THMs had a positive correlation with the chlorine addition in both field research and simulation experiment.

Integrated simulation and optimization scheme of real-time large-scale water supply network: applied to Catalunya case study

This paper presents an integrated simulation and optimization modeling approach in order to provide the optimal configuration for large-scale water supply systems (LSWSS) in real time. Model predictive control (MPC) has been chosen to handle the complex set of objectives involved in the management of LSWSS. The computation of control strategies by MPC uses a simplified model of the network dynamics. The use of the combined approach of optimization and simulation contributes to making sure that the effect of more complex dynamics, better represented by the simulation model, may be taken into account. Coordination between simulator and optimizer works in a feedback scheme, from which both real-time interaction and extensive validation of the proposed solution have been realized using a case study based on the Catalunya regional water network.

A Pump Operation Scheduling Algorithm for Large-Scale Water Supply Systems

The operation of integrated water supply systems has become increasingly complicated owing to reorganization of waterworks. We developed a new method to plan pump operation schedules for large-scale water supply systems. In the proposed method, we define solution space as a network model in which the nodes are cumulative flow rates and the edges are the flow rates at each time step. We treat pump scheduling as a shortest path problem, and the A* search algorithm is used to find the optimum path. One of the characteristics of the proposed method is that the search area is restricted by constraints, such as the water level of tanks. The experimental results show that calculation times increase quadratically, nevertheless, the number of solution states shows an exponential growth with increasing number of pumps. We confirmed that the proposed method can be used effectively for large-scale water supply systems.

Water resources management in central northern Namibia using empirically grounded modelling

In this paper, a new methodology for the analysis and assessment of water supply regimes is presented. The problems of water supply management in developing countries are multidimensional and interdependent. Conventional methods, which only deal with separated and isolated issues, are not appropriate to deal with these problems. The method presented here, however, can comprehend the whole system. Therefore, using this method, conclusions for the management of adapted institutional and technological transformations can be drawn. In this study, relevant system variables of a problem context are identified, and their interdependencies are assessed and interpreted. This is done by using a method of qualitative interview analysis (grounded theory) and a cybernetic modelling approach (sensitivity analysis). In doing so, it is possible to identify outstanding variables which are essential to understand the system. These variables reveal the weakest links, driving forces, systemic stabilisers and the sustainability indicators of the system. The case study area is the Cuvelai-Etosha-Basin in central northern Namibia where a large-scale water supply system has been established. The water supply in the region is determined by the dependence on external water resources, high precipitation variability, absence of perennial rivers, saline groundwater, population growth and urbanisation.

광역상수도 계통의 Pump 운전비용 최소화

광역상수도 계통의 Pump 운전비용 최소화

Application of the Shuffled Frog Leaping Algorithm for the Optimization of a General Large-Scale Water Supply System

A water supply system is a complex network of pipes, canals and storage and treatment facilities that collects, treats, stores, and distributes water to consumers. Increasing population and its associated demands requires systems to be expanded and adapted over time to provide a sustainable water supply. Comprehensive design tools are needed to assist managers determine how to plan for future growth. In this study, a general large-scale water supply system model was developed to minimize the total system cost by integrating a mathematical supply system representation and applying an improved shuffled frog leaping algorithm optimization scheme (SFLA). The developed model was applied to two hypothetical water communities. The operational strategies and the capacities for the system components including water transport and treatment facilities are model decision variables. An explicit representation of energy consumption cost for the transporting water in the model assists in determining the efficacy of satellite wastewater treatment facilities. Although the water supply systems studied contained highly nonlinear terms in the formulation as well as several hundred decisions variables, the stochastic search algorithm, SFLA, successfully found solutions that satisfied all the constraints for the studied networks.

Analysis of a large-scale water supply system of the Byzantine period using modern fluid mechanics

In this paper, the flow of water in several elements of the water supply system of the city of Apamea is simulated. The studied elements were used at the end of the 6th century AD (Byzantine period). These simulations allow for the analysis of the water supply system from a modern point of view, in terms of water flow rate, energy loss, etc. This analysis provides a quantitative description of the water supply system of the city, supplementing the field observations.

Efficient energy management of a large-scale water supply system

Efficient energy management is important for water companies in order to meet economic and environmental targets. For many water supply systems, increased savings can only be accomplished by taking into account the non-linear characteristics of the system in terms of both heads and flows and mixed-integer decision variables. Scheduling must be achieved with complicated tariffs that are frequently changed throughout the year, as well as changes to the network structure. The article shows a case study for energy management of a large-scale network using the computer-aided water network engineering software called FINESSE. The network is a typical large-scale supply network supplying many towns and cities. The model of the network includes 4388 pipes, 35 pumps, 63 variable control valves, 10 non-return valves and 16 variable head reservoirs. The study resulted in a set of mixed-integer optimal schedules that achieved a 14% saving in electrical energy while satisfying operating constraints.

Storage Reservoir Management and Control of a Water Distribution Network in Average Situations as parts of a Control Strategy for a Large Scale Water Supply System

In this contribution two problems connected with the management of a water resources system coupled with the water distribution network will be described. The first one is the control problem for two storage reservoirs. For two developed various control strategies the simulative results will be discussed. The second problem concerns with the control of the water distribution network in case of averages in the system. For them the description of a computer aided decision support system is given.

A space—time hierarchical operation scheduling method for large scale water supply system

A space—time hierarchical operation scheduling method for large scale water supply system

A Space-Time Hierarchical Operation Scheduling Method for Large Scale Water Supply System

A Space-Time Hierarchical Operation Scheduling Method for Large Scale Water Supply System

Development of a Hierarchical Operation Scheduling Model and its' Application to Large Scale Water Supply Systems

A ‘hierarchical operation scheduling model’ is developed to facilitate stable and economical control of all water supply facilities from one central station. The model is structured on three levels. The function of the first level is to calculate the operation schedule of intake stations. The function of the second level is to calculate the operation schedule of purification plants. On this level the whole service area is divided into several zones, and minimum cost flow in the network among the zones is obtained through a primal-dual method. The function of the third level is to calculate the operation schedule of distribution reservoirs. The concept of a calculation module is introduced, and schedules can be laid out for water transportation systems in each zone by using these calculation modules. The hierarchical model is presently in practical use in a city of with a population of 2, 700, 000.