Towards the 'Drainage City': Actions and Tools for Soil Deimpermeabilisation

The epistemology of risk (articulated in hazard, vulnerability, and exposure) has reached such maturity in scientific terms, in its widespread perception and, though not entirely, in the national public discourse, that it demands an extensive and taxonomic study of the techniques and tools relating to the 'water cycle' of contemporary cities and territories. It is precisely in the relationship with water that the city project intervenes, at different scales, with greater success on the different vulnerabilities of different contexts induced by climate change. And if one can act on water (the tradition is thousands of years old), one cannot act on winds, which are also subject to great changes, as Gilles Clément recently reminded us. The 'drainage city' investigates and re-designs precisely the relationship between the built environment resulting from the relationship between impermeable/permeable/renaturalised soil and the water cycle, triggering some effects and limiting others that reconfigure the overall performance of the whole living environment. The research needs a comparison with the advancement of the issue in the national and international context: today field of studies, experiences, practices, and standards that can be traced back to the so-called Adaptive Planning and Urban Design. In relation to this, the main objective of the paper is to recognize from general to specific usefulness and field of application (with particular attention to different scales and urban and territorial geographies) of the so-called de-sealing techniques, meaning by this, the various forms of subtraction of built spaces that imply the de-impermeabilisation of the soil (literally " to unseal"), including among these also those more specific to "sustainable urban drainage systems". The methodology will therefore consist of a comparative analysis that will imply the identification and systematization of "techniques" and "fields of application"; firstly, starting from the reconstruction of a registry deduced from a disciplinary literature with no national boundaries, and subsequently, with a specific investigation in the Italian context of state of the art. Therefore, the investigation will tend to move on three levels aimed at constructing the properly operational tool such as the Synoptic Framework of Techniques, Fields of Application, and Standards. The first level will concern the multiplicity/variety of aspects and specific conditions recognizable in the sources considered (objectives, outcomes, geographies, scales, supporting financial sources, etc.); the second, the possible correlations with the tools of government/land management; the third, a comparison between the two previous levels in the national and international field.