Historic records and GIS applications for flood risk analysis in the Salento peninsula (southern Italy)

Abstract. The occurrence of calamitous meteoric events represents a current problem of the Salento peninsula (Southern Italy). In fact, flash floods, generated by very intense rainfall, occur not only in autumn and winter, but at the end of summer as well. These calamities are amplified by peculiar geological and geomorphological characteristics of Salento and by the pollution of sinkholes. Floodings affect often large areas, especially in the impermeable lowering zones. These events cause warnings and emergency states, involving people as well as socio-economic goods.

A methodical investigation based on the historic flood records and an analysis of the geoenvironmental factors have been performed, using a Geographic Information System (GIS) methodology for database processing in order to identify the distribution of areas with different risk degrees. The data, referring to events that occurred from 1968 to 2004, have been collected in a database, the so-called IPHAS (Salento Alluvial PHenomena Inventory), extracted in an easily consultable table. The final goal is the development of a risk map where the areas that are affected by floodings are included between small ridges, the so-called "Serre". More than 50% of the Salento peninsula shows high or very high risk values. The numerous maps that were utilized and generated represent an important basis in order to quantify the flood risk, according to the model using historic records.