Performance indicators in water distribution systems aggregated by means of bayesian networks

The current arrangement of the water distribution systems, both at a national and at an international level, makes it necessary an evaluation of the different distribution networks. This has encouraged the development of different comparison techniques. Among them, an undoubtfully fundamental instrument is represented by the Performance Indicators (PI). The PIs can be defined as a quantitative measurement of a particular aspect of a company performance or service qualitative standard. Relatively to the issue of water supply system losses, the industry's literature offers various groups of consolidated and widely-applied indicators, though none of them may be considered to be completely exhaustive in both methodology and completeness. The analysis of the different groups of indicators suggests the need for an integration and homogenization of these groups, in order to identify a common methodology capable of finding and monitoring the different aspects of the problem. This process has underlined the necessity of identifying a procedure to organize the evaluation of the performance at different scales, and thus at different levels, according to the Observatories' strategies involved into the evaluation. In this paper, a bayesian model of evaluation is described and is applied to a district of the water distribution network of the Modena city.