Introduzione allo studio delle pianure minori italiane

An Introduction to the study of minor plains Italy

Abstract

The number and the quality of the studies about plains are far inferior to the ones about mountains. If that is natural considering the amount of scientific information that can be obtained from the latter, it is no longer so if we consider the greater importance that plains acquire with reference to human settlement. Italian minor plains need a substantial development of the knowledge of them, as they are the areas where the highest levels of population and economic development of the peninsula and of the Italian isles as well can be found. Minor plains in Italy are, first of all, closely linked with the tectonic areas in which they are situated, which are nearly always unstable, because of the still active Neotectonics of the Italian region. However, the importance of the latest phenomena, such as the upwelling of the sea to the present levels after the Würm regression with the consequent change in morphogenesis, leads to distinguish older morphoneotectonic evolution from Holocene evolution. Considering the keen a interest that is attached to the study of surface morphology, as experiments relating to the other plains that were carried out elsewhere prove, the main starting-point for research lies in geomorphologic survey and mapping. On the other hand, the necessity of getting to know the substratum leads to find all the data drillings and geophysic and gravimetric surveys that have been so far carried out, and also to their filing in a data bank. Another fact of great interest lies in the knowledge of fluvial dynamics (and of climate), considering that the regimen of rivers in Italy is very various, with the borderline case of southern «fiumare» (broad rivers that are usually dry). And yet, if we cannot think of developing these themes in a short time, we must admit that in some cases the data that we have got already enable us to make an attempt of hydro-fluvial models. It is still necessary to link this type of study with the studies about the geomorphologic evolution of the basin. However considering the increasing attention devoted to extreme events, which seem to have a decisive influence on morphogenesis, it would be advisable for us to start the cataloguing and the study of said events relating to the various Italian plains. On the contrary the need to get better knowledge of the process of progradation and aggradation of coastal plains passes through the link between sedimentological studies and the wide knowledge, even as regards historic times, of the changes of coastline that we have got. A cartographic and historic survey of the areas flooded in the past cannot but be the right foreword to the research for areas that might be flooded. The capability of reckoning the hazard of a flooding is highly compromised by the endless alteration of the natural environment of plains as a consequence of the unending using up of space, due to urbanisation, and the enbankement and impermeabilisation of valley slopes and valley bottoms. It is enough to say that, in the post-war years, a flat surface equivalent to a medium Italian regions was «stolen» from agriculture and industry in consequence of building and road making. As Italian minor plains are very different one from another for physical and climatic aspects and for their different human settlements numerous and detailed studies about each of them are necessary before being able to get geographic and geomorphologic outlines.