A proper land-use planning through the use of historical research

Description

Natural instability processes like landslides, muddebris flows and floods are the most frequent geohydrological phenomena in Piedmont (north-western Italy). They can involve urbanized areas and consequently can generate risk-prone areas according to the geomorphological features of the territory. Piedmont has been hit by five relevant events in the last 20 years (September 1993, November 1994, October 1996, October 2000 and May 2008): geohydrological processes have caused fatalities and damage for several hundred million Euros. The aim of this study is to evaluate the spatialtemporal distribution of the natural instability processes over the past two centuries and to relate it to the current land planning: that can permit to identify the hazard-prone areas that can become riskprone areas when urbanized areas are involved. The study area (1,200 km2) is located in the north-western Italy (Piedmont). The methodology has been carried out by the following steps: a) analysis and interpretation of historical documents gathered in the Archive of the Research Institute for Geo-Hydrological Protection of the National Research Council (CNR-IRPI). In the IRPI of Turin, in fact, there is the richest Italian archive of information about natural instability processes occurred in the north of Italy; b) drafting of descriptive records into a geodatabase; c) localization of the natural instability processes using GIS; d) synthesis and data processing and e) case studies: comparison between geomorphological effects and the current land planning. The gathered documents of 24 municipalities were deeply analyzed and about 900 records were filled and georeferenced. They have permitted to have a more detailed picture of the main natural instability processes which affected the examined area and the relative damage. This study has highlighted that a correct territorial planning for the prevention and mitigation of geohydrological risk cannot ignore the wealth of information that can be obtained from historical research.

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