En este estudio se presenta una formulación alternativa para la Regla de Cobertura Óptima (RCO) cuyo objetivo es la determinación del la descarga óptima de embalses. Se presenta una función de pérdida de embalse para condiciones de escasez. Dicha función de pérdida de embalse se expresa como función la demanda y almacenamiento requeridos, con respecto del caudal de operación (descarga) y del almacenamiento operacional del embalse, respectivamente. Se presenta la formulación matemática de RCO y se establecen los intervalos de validez. La operación del embalse se realiza mediante un balance de masa (i) Se presenta el caso para el embalse de Riogrande II, Colombia; (ii) se presenta la calibración de la regla de operación estándar (ROE) y de la RCO para periodos mensuales y anuales, y se compara su ajuste de calibración entre observado y simulado; (iii) para el mejor escenario de calibración, se presenta un análisis de sensibilidad de operación para 3 criterios de escasez y 3 criterios de excesos. (iv) Posteriormente la operación calibrada se aleja de los valores mínimos de los seis criterios, se realiza una optimización multi-criterio usando Borg MOEA, y se demuestra de forma teórica la operación óptima de dicho embalse para evitar desabastecimiento o racionamiento en periodos futuros.@en

Most developments for Water Distribution Network (WDN) modeling purposes refer to optimization approaches for design, rehabilitation or operation. However, most case studies presented in the literature are rather small and represent only a small portion or simplification of a network. The city of Milano with a population of around 1.3 million inhabitants is an example of a WDN where many phenomena occur simultaneously and where the utility, Metropolitana Milanese S.p.A, (MM), needs to deal with many factors for its daily operation. Under the framework of the EU-FP7 ICeWater project, a new model for the WDN of the city of Milano has been developed with UNESCO-IHE, during the last 2.5 years. This article presents the process of model building, the challenges for the calibration process, open issues and tasks to be developed in the near future.@en

Sectorization is an effective technique for reducing the complexities of analyzing and managing of water systems. The resulting sectors, called district metering areas (DMAs), are expected to meet some requirements and performance criteria such as minimum number of intervention, pressure uniformity, similarity of demands, water quality and number of districts. An efficient methodology to achieve all these requirements together and the proper choice of a criteria governing the sectorization is one of the open questions about optimal DMAs design. This question is addressed in this research by highlighting the advantages of three different criteria when applied to real-word water distribution networks (WDNs). To this, here it is presented a two-stage approach for optimal design of DMAs. The first stage, the clustering of the system, is based on a Louvain-type greedy algorithm for the generalized modularity maximization. The second stage, the physical dividing of the system, is stated as a two-objective optimization problem that utilises the SMOSA version of simulated annealing for multiobjective problems. One objective is the number of isolation valves whereas for the second objective three different performance indices (PIs) are analyzed and compared: (a) standard deviation, (b) Gini coefficient and (c) loss of resilience. The methodology is applied to two real case studies where the first two PIs are optimized to address similar demands among DMAs. The results demonstrate that the proposed method is effective for sectorization into independent DMAs with similar demands. Surprisingly, it found that for the real studied systems, loss of resilience achieves better performance for each district in terms of pressure uniformity and demand similarity than the other two specific performance criteria.@en

The Eastern Nile Basin is facing a number of transboundary issues, including water resources development, and the associated impacts. The Nile Basin, particularly the Eastern Nile Sub-basin, is considered as one of a few international river systems of potential conflicts between riparian countries. The Eastern Nile is characterized by the high dependency of downstream countries on river water generated in upstream countries, with limited or no contribution to the runoff itself. The aim of this paper is to analyze optimal scenarios for water resources management in the Eastern Nile with regard to hydropower generation and irrigation development. A hydro-economic optimization model based on Genetic Algorithm has been used to determine the maximum benefits for two scenarios: (i) non-cooperative management of hydraulic infrastructure by the riparian countries (status quo), and (ii) cooperative water resources management among the riparian countries. The hydro-economic model is developed using a Genetic Algorithm and deterministic optimization approach covering all hydraulic infrastructures in the Eastern Nile, existing and planned, including the Grand Ethiopian Renaissance Dam (GERD). The results show that cooperative management yields an increase in hydro-energy returns for all countries compared to the status quo, with a very high increase in Ethiopian's returns, as expected. Non-cooperative system management would negatively impact the hydro-energy of Egypt compared to the cooperative management (reduced by 11%), without a significant increase of hydro-energy for Ethiopia. For Sudan, the results show that hydropower generation benefits from the presence of GERD, in both management scenarios. Non-cooperative management of the system, along with the internal trade-off between irrigation and hydropower facilities, would negatively impact irrigation supply in Sudan. The findings support the argument of positive impact of GERD development on the three Eastern Nile riparian countries, Ethiopia, Sudan and Egypt, provided that the three countries agree to manage the system cooperatively.@en

Wastewater effluents from irrigation and the domestic and industrial sectors have serious impacts in deteriorating water quality in many rivers, particularly in areas under tidal influence. There is a need to develop an approach that considers the impact of human and natural causes of salinization. This study uses a multi-objective optimization–simulation model to investigate and describe the interactions of such impacts in the Shatt al-Arab River, Iraq. The developed model is able to reproduce the salinity distribution in the river given varying conditions. The salinity regime in the river varies according to different hydrological conditions and anthropogenic activities. Due to tidal effects, salinity caused by drainage water is seen to intrude further upstream into the river. The applied approach provides a way to obtain optimal solutions where both river salinity and deficit in water supply can be minimized. The approach is used for exploring the trade-off between these two objectives.@en

Sectorization is a wide used technique that reduces the complexities associated with the analysis and management of drinking water networks. The districts resulting from sectorization are expected to meet certain performance criteria, such as the minimum number of interventions, uniformity in pressures, and similarity in demands, among others. Developing a methodology for optimal district design that meets some of these requirements is an significant challenge. In this work, the advantages in the use of three different criteria are compared. To this, a two-stage approach is presented. The first stage, the communities detection, is based on a Louvain-type algorithm for the maximization of modularity in weighted networks. The second stage, the physical division of the system, is posed as a two-objective optimization problem using a simulated annealing algorithm. The first of these objectives is the number of isolation valves, while for the second objective three different indices are studied: (a) Loss off resilience,(b) Gini coefficient and (c) Standard deviation, the last two are defined to quantify pressures uniformity. The methodology is applied to real study case: a medium-sized network.@en

Large water distribution networks require efficient use of their resources. One of the ways to become more efficient is to reduce the energy consumption due to pumping systems [1] [2]. In the European context the city of Milan has a large water supply system for 1.3 million inhabitants and around 4.0 million commuters, which is supplied entirely by 26 pumping stations. The system currently supplies its ∼50,000 customers with 103 pumps which are actively operated during the day [3]. In previous years a pump scheduling algorithm has been proposed to the utility for a Pressure Management Zone (PMZ) in the south of the city named Abbiategrasso containing only 4 pumps [4] [5]. However, it is of the interest for the utility to extend the analysis to the whole system [6] [7]. For that reason it is necessary to perform a proper pump scheduling. The solution proposed here, is a Multi-Objective Optimization (MOO) for the energy consumption reduction of the whole Water Distribution Network (WDN) using an EPANET model of the whole network. Results show that there is room for improvement of energy and pressure management in the system. The solution presented here can be applied to other utilities with similar challenges.@en

Large water distribution networks require efficient use of their resources. One of the ways to become more efficient is to reduce the energy consumption due to pumping systems [1] [2]. In the European context the city of Milan has a large water supply system for 1.3 million inhabitants and around 4.0 million commuters, which is supplied entirely by 26 pumping stations. The system currently supplies its ∼50,000 customers with 103 pumps which are actively operated during the day [3]. In previous years a pump scheduling algorithm has been proposed to the utility for a Pressure Management Zone (PMZ) in the south of the city named Abbiategrasso containing only 4 pumps [4] [5]. However, it is of the interest for the utility to extend the analysis to the whole system [6] [7]. For that reason it is necessary to perform a proper pump scheduling. The solution proposed here, is a Multi-Objective Optimization (MOO) for the energy consumption reduction of the whole Water Distribution Network (WDN) using an EPANET model of the whole network. Results show that there is room for improvement of energy and pressure management in the system. The solution presented here can be applied to other utilities with similar challenges.@en

In Colombia there are few river basins that could not be represented inside bigger hidrosystems like Magdalena, Cauca, Orinoco and Amazonas. This so called automata systems are pretty overlooked by scientist cause they usually become a very far central urban population cities. Patia basin is one of those, located right in the south of the Colombian pacific, and should be seen that it drains something like 22000 km2. Actually in the country exist very few investigation related with the behavior of monthly average flows in this river and his tributaries. A preview publication was developed trying to fulfill the basic characteristics of the mean multiannual stream flows of the river basin. However, they’ve failed to accomplish the task due to little issues. The first one, the analysis was made only taking into account a few points of the main stream of the Patia basin; second, the model used corresponds to an indirect rainfall-stream flow one, without comparing it to the whole series of data available. So that became the main reason of exploring even more deep the temporal configuration of the stream flows in that basin. It could be noticed that many investigations could be elaborated further for the physical understanding of the stream flows in this region of the country.@en

The application of Information and Communication Technologies (ICT) for water supply systems has steadily increased in the last 20 years. The city of Milan is presented as case study where the main challenge for the coming 20 years is the efficient use of energy. Opposite to other parts of the world, in Milan, water is neither scarce nor there is a growing need for supply. Given that the system completely relies on pumping, optimization algorithms and sensor technologies can be applied to reduce energy consumption. This article presents research in optimization for Pump Scheduling (PS), carried out under the framework of the ICeWater project (funded by EU-FP7). For this purpose approaches using two multi-objective optimization algorithms (Nondominated Sorting Genetic Algorithm - NSGA-II and Archive based Micro-Genetic Algorithm -AMGA2) have been applied. The results indicate that a tangible energy consumption reduction can be achieved by using pump scheduling optimization. @en

The application of Information and Communication Technologies (ICT) for water supply systems has steadily increased in the last 20 years. The city of Milan is presented as case study where the main challenge for the coming 20 years is the efficient use of energy. Opposite to other parts of the world, in Milan, water is neither scarce nor there is a growing need for supply. Given that the system completely relies on pumping, optimization algorithms and sensor technologies can be applied to reduce energy consumption. This article presents research in optimization for Pump Scheduling (PS), carried out under the framework of the ICeWater project (funded by EU-FP7). For this purpose approaches using two multi-objective optimization algorithms (Nondominated Sorting Genetic Algorithm - NSGA-II and Archive based Micro-Genetic Algorithm -AMGA2) have been applied. The results indicate that a tangible energy consumption reduction can be achieved by using pump scheduling optimization. @en

The pressure control in water distribution networks represents one of the main foundations to achieve an effective policy in the management of background leakages. Dividing the network into district meter areas is a useful strategy to simplify the analysis and management of these hydraulic systems. In this work, a two-stage methodology for pressure control is proposed. In a first stage, the network sectorization is obtained by maximizing the index of modularity for weighted networks. The design variables are the valve positions that delimit the desingned districts. In the second stage, the optimal operating conditions of the valves are determined by minimizing the standard deviation of the network pressures. The proposed methodology is applied to an academic network and proves to be efficient to achieve the reduction of peak pressures.@en

The pressure control in water distribution networks represents one of the main foundations to achieve an effective policy in the management of background leakages. Dividing the network into district meter areas is a useful strategy to simplify the analysis and management of these hydraulic systems. In this work, a two-stage methodology for pressure control is proposed. In a first stage, the network sectorization is obtained by maximizing the index of modularity for weighted networks. The design variables are the valve positions that delimit the desingned districts. In the second stage, the optimal operating conditions of the valves are determined by minimizing the standard deviation of the network pressures. The proposed methodology is applied to an academic network and proves to be efficient to achieve the reduction of peak pressures.@en

The pressure control in water distribution networks represents one of the main foundations to achieve an effective policy in the management of background leakages. Dividing the network into district meter areas is a useful strategy to simplify the analysis and management of these hydraulic systems. In this work, a two-stage methodology for pressure control is proposed. In a first stage, the network sectorization is obtained by maximizing the index of modularity for weighted networks. The design variables are the valve positions that delimit the desingned districts. In the second stage, the optimal operating conditions of the valves are determined by minimizing the standard deviation of the network pressures. The proposed methodology is applied to an academic network and proves to be efficient to achieve the reduction of peak pressures.@en

The pressure control in water distribution networks represents one of the main foundations to achieve an effective policy in the management of background leakages. Dividing the network into district meter areas is a useful strategy to simplify the analysis and management of these hydraulic systems. In this work, a two-stage methodology for pressure control is proposed. In a first stage, the network sectorization is obtained by maximizing the index of modularity for weighted networks. The design variables are the valve positions that delimit the desingned districts. In the second stage, the optimal operating conditions of the valves are determined by minimizing the standard deviation of the network pressures. The proposed methodology is applied to an academic network and proves to be efficient to achieve the reduction of peak pressures.@en

A digital twin (DT) is a virtual copy (a digital model) of a real system continuously fed with data to mimic the systems’ past, present and future behaviour. This makes it possible to detect anomalies, test new ideas and changes in the virtual system and assess how it reacts, minimizing the risks to the real system. In this sense, the DT can be seen as a playground to explore the effects of different scenarios and to practice how to best react and operate the physical system under these circumstances. The concept of DT has been used traditionally in the industry field1 but it can also be developed and exploited in a city management context, and in particular in Water Supply and Distribution Networks (WSDN), where it can be applied to all aspects of the system@en

A digital twin (DT) is a virtual copy (a digital model) of a real system continuously fed with data to mimic the systems’ past, present and future behaviour. This makes it possible to detect anomalies, test new ideas and changes in the virtual system and assess how it reacts, minimizing the risks to the real system. In this sense, the DT can be seen as a playground to explore the effects of different scenarios and to practice how to best react and operate the physical system under these circumstances. The concept of DT has been used traditionally in the industry field1 but it can also be developed and exploited in a city management context, and in particular in Water Supply and Distribution Networks (WSDN), where it can be applied to all aspects of the system@en

A digital twin (DT) is a virtual copy (a digital model) of a real system continuously fed with data to mimic the systems’ past, present and future behaviour. This makes it possible to detect anomalies, test new ideas and changes in the virtual system and assess how it reacts, minimizing the risks to the real system. In this sense, the DT can be seen as a playground to explore the effects of different scenarios and to practice how to best react and operate the physical system under these circumstances. The concept of DT has been used traditionally in the industry field1 but it can also be developed and exploited in a city management context, and in particular in Water Supply and Distribution Networks (WSDN), where it can be applied to all aspects of the system@en

A digital twin (DT) is a virtual copy (a digital model) of a real system continuously fed with data to mimic the systems’ past, present and future behaviour. This makes it possible to detect anomalies, test new ideas and changes in the virtual system and assess how it reacts, minimizing the risks to the real system. In this sense, the DT can be seen as a playground to explore the effects of different scenarios and to practice how to best react and operate the physical system under these circumstances. The concept of DT has been used traditionally in the industry field1 but it can also be developed and exploited in a city management context, and in particular in Water Supply and Distribution Networks (WSDN), where it can be applied to all aspects of the system@en

Severe flood events in China are a common cause of life losses. Many efforts have been carried out by the Yellow River Conservancy Commission (YRCC) to understand flood development and impact on the Yellow River. Modeling approaches based on discretization of the modeled domain in square and rectangular grids have great importance in the management of rivers, but they usually present two drawbacks: the required accuracy of the meandering of wide long rivers is not well represented, and the need to use many grid cells reduces computational speed. Modeling and simulation of extreme flood events using unstructured grids has not yet been applied to the Yellow River. This study shows how such a method can be beneficial to decision makers in the Yellow River region in case of flood events. The research shows that a flexible mesh discretization of the domain can overcome the two drawbacks. Along with a test of the proposed modeling method, new characteristics of the spatial evolution of flood events in the Yellow River emerged and are presented, showing the capabilities of DFloridaOW-FM software in modeling such a complex system.@en