Activities carried out within the project framework are manifold and can be grouped into 4 categories, namely:
The inventory
The inventory of historical information on landslides and floods represents the most important and qualifying activity carried out within the project. The first inventory was completed by 17 research teams that worked for one year on the project. Twenty-two journals were systematically searched for the period 1918-1990, and 350,000 newspaper issues were screened. About 150 experts on mass-movements and floods were interviewed and more than 1000 published and unpublished technical and scientific reports were reviewed.
The inventory was updated for the period 1991-1994 by two research teams that searched 55 local or regional journals, for a total of about 70,000 newspaper issues screened. During the update several events that occurred prior to 1991 were inventoried. A second update for the period 1995-1996 is sheduled and will be completed by mid 1999. The update will be carried out by searching more than 50 local journals, as well as the 1800 publications and reports edited by CNR-GNDCI.
Validation consists in the assessment of the information completeness and reliability. The information was stored into a computer archive that, in its present structure, is composed by two databases, one for mass-movements and one for floods. Each database has more than 20 relational tables, for a total of about 34.000 records. Several tables were checked for typing and grammatical errors as well as for inconsistencies, most of witch were corrected.
Current validation efforts aim at comparing the information stored into the computer databases against the original archive forms, compiled during the inventory. The consistency check is due to be completed by the end of 1998.
Dissemination and diffusion of the historical information is a goal of primary importance for the project. Among the efforts that have been made to make the information available it is worth mentioning:
The historical information inventoried by the project is used by local and regional organisations, and in particular by River Authorities, to evaluate hydrological hazard and to prepare thematic maps and related documents.
From a scientific point of view, the possibility of using historical data to evaluate geological and hydrological hazard and risk at various scales in being investigated. Experiments were carried out in particular in the Tiber River basin, in central Italy.
For the Tiber River basin the historical archive reports 894 sites affected by 1689 landslide events and 324 sites affected by 1232 inundation events.
The histogram shows on the x axis the total number of inundated sites, and on the y axis the number of times each site was inundated, that is the frequency of inundated sites. The number of inundated sites is quite large (324 sites) but sites affected recursively (in blue) are limited in number (less than 25). Similar graphs were prepared for each of the 20 Italian regions. For most of the regions the number of inundated sites is large, confirming that flooding is widespread, but also that sites more frequently inundated are relatively few.
Experiments were made to determine the feasibility of using the historical catalogue of information on mass-movements and inundation to define regional alarm or warning thresholds.
The graphs show for the Ponte Nuovo di Torgiano (Perugia) and for the Ponte di Ripetta (Rome) gauging stations the relationships between the occurrence of catastrophic events (i.e., landslides and floods) and the hydrological conditions (i.e., peak mean daily discharge and total flood volume) of the river basin. Information on landslides and floods was obtained from the historical archive. Hydrological conditions were ascertained from the historical record of mean daily discharge values published by the Servizio Idrografico e Mareografico Nazionale. The most damaging events (red squares), for witch both landslides and inundation are reported, are located where the hydrological conditions are more severe, i.e., where water level is higher and flood volume is larger.
