Urban Plan and Water Infrastructures Planning: A Methodology Based on Spatial ANP

Cities are exploding, occupying rural territory in dispersed and fragmented ways. A consequence of this phenomenon is that the demand for utilities includes more and more extensive territories. Among them, fulfilling the demand for services related to integrated water service presents many difficulties. The economic costs needed to meet service demand and the environmental costs associated with its non-fulfilment are inversely proportional to the population needing service in rural areas, since that population is distributed across a low-density gradient. Infrastructure planning, within the area of competence, generally follows a policy of economic sustainability, fixing a service coverage threshold in terms of a “sufficient” concentration of population and economic activity (91/271/CEE). This threshold, homogenous within the territorial limits of a water infrastructure plan, creates uncertainty in the planning of investments, which are not sized on the actual, appropriately spatialized, demand for service. Careful prediction of the location of infrastructure investments would guarantee not only economic savings but also reduce the environmental costs generated by the lack of utilities. Therefore, is necessary to create a link between water infrastructure planning and urban planning, which is responsible for the future spatial distribution of service demand. In this study, the relationships between the instruments of regulation and planning are compared by a multi-criteria spatial analysis network (analytic network process (ANP)). This method, tested on a sample of a city in southern Italy, allows us to optimize the design and location of the investment needed to meet the service criteria, looking at the actual efficiency of the networks. The result of this application is a suitability map that allows us to validate the criteria for defining urban transformations