Evaluating infrastructure alternatives for regional water supply systems by model-assisted cost-benefit analysis – a case study from Apulia, Italy

The main challenge associated to regional water supply systems planning lies in understanding the best infrastructure alternatives to improve service given a certain configuration of the resources system. While cost-effectiveness assessments are still widespread in this type of analyses, they do not account for the fact that, especially in mature systems, service improvements tend to follow the law of marginal diminishing returns, so that a cost – benefit assessment should be preferable. Both costs and benefits can be organized into a cost-benefit analysis (CBA) framework. In a complex system, a model reproducing its topology and characteristics better describes the impacts of the alternatives. In this work some alternatives to improve service in the regional water supply system of Apulia, Southern Italy, are illustrated and compared through CBA. The system has been modelled through AQUATOR, a state-of-the-art simulation software package.