M.E. Castro Gama
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This research deals with two different aspects of operations of water distribution networks related to energy minimization and pressure management. Both problems are dealt through model-based optimization via pump scheduling and water network sectorization. The research findings are a stepping stone to improved operation of large water distribution systems where assets are known and there is a need for improvement of energy use. Both optimization problems have been performed using simulations made with EPANET 2.0, linked to heuristic algorithms. Due to the large number of optimization runs, High Performance Computing (HPC) was also employed, using the national computing grid of the Netherlands for research and educational institutions, named SURFSara HPC Cloud, and, to some extent using Microsoft Azure®..... ...
This research deals with two different aspects of operations of water distribution networks related to energy minimization and pressure management. Both problems are dealt through model-based optimization via pump scheduling and water network sectorization. The research findings are a stepping stone to improved operation of large water distribution systems where assets are known and there is a need for improvement of energy use. Both optimization problems have been performed using simulations made with EPANET 2.0, linked to heuristic algorithms. Due to the large number of optimization runs, High Performance Computing (HPC) was also employed, using the national computing grid of the Netherlands for research and educational institutions, named SURFSara HPC Cloud, and, to some extent using Microsoft Azure®.....
Water distribution network (WDN) models are a common decision support tool for understanding the behavior and performance of WDNs, aiding in the planning and management of WDN systems. The increasing availability of real-time data has recently promoted the exploration of Data Assimilation (DA) techniques to improve these models. However, flow, pressure and demand data are uncertain, particularly due to sensor characteristics such as precision and noise. An open question is to what extent DA can still improve hydraulic models when the data used to this end is uncertain. This paper proposes a three-step Ensemble Kalman Filter based DA approach for WDNs (3-EnKF-WDN), building on previous approaches, and advancing in two main fronts: the use of extended period simulation, and the use of pressure-dependent demand (PDD) analysis. Different scenarios considering uncertain sensor data, with varied precision and noise, are applied to two networks of different sizes, representative of real-world WDNs. The computational demand of the 3-EnKF-WDN method is also assessed. Results show that increasing sensor’s precision and decreasing the noise in state measurements reduce model error, as expected. However, we also found that model errors: 1) are reduced more effectively by using 3-EnKF-WDN than by increasing sensors’ precision; 2) are not reduced if certain noise thresholds are surpassed; 3) can be reduced without assimilating demand data if the WDNs are fully monitored with head sensors in all the nodes and flow sensors in all the links.
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Caso de estudio: Riogrande II, Colombia
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.
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.
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.