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Application of optimization algorithms to design and operation of water supply systems

Keywords: energy efficiency, design, optimization, water scarcity, water supply systems
Fig. 1. Framework of GHEST algorithm (Authors: Bolognesi A., Bragalli C.)
Fig. 2. Optimal design of water supply system using GHEST (Authors: Bolognesi A., Bragalli C.)

Water distribution systems are complex and extensive systems, characterized by significant temporal variability of users’ demand and, in some cases, even of supply sources. This means that interventions must be evaluated for different operational conditions. The search for optimal solutions in economic terms, so to satisfy the functional constraints and performance levels, has become more important with the Law 36/94, which introduced the criteria of entrepreneurship, and also the necessity to reduce the environmental impact in terms of water and energy needs for drinking water. Planning and management problems can be translated into an optimization problem where a set of solutions are found, from which the decision maker can find the final one. The optimization problem is of NP-hard type and is extremely complex due to the nonlinearity of the equations of motion and the presence of discrete variables. To overcome these difficulties heuristic algorithms able to explore the solution space in a stochastic way are applied, leaving to the simulator just the numerical solution of the hydraulic equations. Optimization algorithms considered in the research are manyfold. Multi-objective genetic agorithm (MOGA) NSGA-II based on analogy of evolution in nature has been used in collaboration with University of Exeter (UK). Also, in collaboraztion with CINECA Center, NSGA-II parallelization has been developed. An evolutionary algorithm named GHEST (Genetic Heritage Evolution by Stocastic Transmission) of recent development has been tested on several water distribution networks. Finally, an exact Mixed Integer Non Linear Programming approach has been used in collaboration with the Department DEIS of University of Bologna. The optimization techniques can be applied in the search of appropriate strategies for the mitigation of the effects of water scarcity. Water supply systems have now reached a high degree of complexity. The research may help to improve, through developments of modelling and analysis tools, the assessment of impact on urban area of possible prevention and mitigation actions actions.

Main publications

Artina S., Bolognesi A., Bragalli C., D'Ambrosio C., Marchi A. (2011). Comparison among best solutions of the optimal design of water distribution networks obtained with different algorithms. In: CCWI 2011 Urban Water Management: challenges and opportunitis.

Artina S., Bragalli C., Erbacci G., Marchi A., Rivi M. (2012). Contribution of parallel NSGA-II in optimal design of water distribution networks. Journal of Hydroinformatics, vol. Volume: 14 (2) p. 310-323, ISSN: 1464-7141

Bolognesi A., Bragalli C., Marchi A., Artina S., Genetic Heritage Evolution by Stocastic Transmission in the optimal design of water distribution networks, Advances in Engineering Software – Elsevier 41 (2010) 792-801.

Bragalli C., D’Ambrosio C., Lee J., Lodi A., Toth P. (2006). An MINLP Solution Method for a Water Network Problem. LECTURE NOTES IN COMPUTER SCIENCE. Algorithms – ESA 2006. Zurich, Switzerland. September 11-13, 2006. vol. 4168, pp. 696 - 707 ISSN: 0302-9743.

Bragalli C., D'Ambrosio C., Lee J., Lodi A., Toth P. (2008). Water network design by MINLP. p. 1- 18, NEW YORK:IBM Reserach.

Bragalli C., Marchi A., Bolognesi A., S. Artina S., Todini E. (2010). Applicazione dell’algoritmo euristico ghest al progetto della rete idrica di Balerma, XXXII Convegno Nazionale di Idraulica e Costruzioni Idrauliche Palermo, 14-17 settembre 2010

Bragalli C, C. D'Ambrosio, J. Lee, A. Lodi, P. Toth (2012). On the Optimal Design of Water Distribution Networks: a Practical MINLP Approach. OPTIMIZATION AND ENGINEERING, vol. 13, p. 219-246, ISSN: 1389-4420.

Bolognesi A., Marchi, A., Bragalli, C., Artina, S. (2014). Multi-objective design of water distribution networks through the generation of pseudofronts in the hydraulically feasibile region. Journal of Comp. in Civ. Eng. ASCE, vol. 28 (4).

Bolognesi A., Bragalli C., Artina S. (2012). Ottimizzazione di una rete di distribuzione idrica nela rispetto integrale del livello di servizio. In: XXXIII Convegno di Idraulica e Costruzioni Idrauliche. p.1-14, Cosenza:Edibios, ISBN: 978- 88-97181-18-7, Brescia, 10-14 settembre 2012

Bragalli C., Freni G., La Loggia G. (2007). Assessment of water shortage in urban areas. WATER SCIENCE AND TECHNOLOGY LIBRARY, p. 375-398, DORDRECHT:Springer, ISBN: 9781402059230.

Conte G., Bolognesi A., Bragalli C., Branchini S., Carli A.D., Lenzi C., Masi F., Massarutto A., Pollastri M., Principi I. (2012). Innovative Urban Water Management as a Climate Change Adaptation Strategy: Results from the Implementation of the Project “Water Against Climate Change (WATACLIC)”. WATER, ISSN: 2073-4441, vol. 4, p. 1025-1038.

D’Ambrosio C., Lodi A., Wiese S., Bragalli C. (2015). Mathematical programming techniques in water network optimization. EUROPEAN JOURNAL OF OPERATIONAL RESEARCH ISSN:0377 2217, vol.243 (3), p.774-788.

Research projects

LIFE08/INF/IT/000308 "WATACLIC - WATER AGAINST CLIMATE CHANGE. Sustainable water management in urban areas", approvato dalla CE (2010 - 2012).

FP7-ENV-2010 TRUST - Transactions to the Urban Water Services of Tomorrow.

INTERREG IV C "WATER CoRe WATER SCARCITY AND DROUGHTS - COORDINATED ACTIVITIES IN EUROPEAN REGIONS" Priority 2: Environment and Risk Prevention, Sub-Theme: Water Management, approvato dalla CE (2010 - 2013)..