Debris flows triggered by 25th October 2011 event in Val di Vara (Liguria, Italy) The The flood flood event event – – spatial spatial and and temporal temporal dynamics dynamics (original) (raw)
The present work reports a preliminary assessment on landslides triggered by the heavy rainfall of 25 th October 2011 that caused extensive damage in Cinque Terre and Lunigiana (Liguria and Tuscany). ISPRA has undertaken a post-event field survey focused on the Vara river basin mainly finalised to a preliminary evaluation of geomorphological and hydrological processes triggered by the storm and their interconnection with environmental and human settings. The investigated area, i.e. the sub-basin of Brugnato and Borghetto Val di Vara municipalities, has an extension of about 100 Km 2. In the above area, mainly pelitic-arenaceous and shale formations, generally covered by 1-2m strongly weathered debris thick, are outcropping. About 90 landslides phenomena, at the scale 1: 10,000, were surveyed. The prevalent landslide types are: 1) debris-slide of weathered bedrock and colluvium, developed along a planar surface sub-parallel to the slope; 2) debris-avalanches characterized by partially or fully-saturated material on open slopes; 3) diffused channeled debris-flow of fully-non plastic material triggered along the minor stream network. This study has the purpose to support future implementation of landslide mitigation works and safety measures of the area such as structural (e.g. works for protection of urban areas and consolidation of potentially unstable material) and non-structural interventions (e.g. monitoring, legal bindings, delocalisation). A specific survey on potential damage suffered by landslide mitigation works funded by the Ministry of the Environment (Decree 180/98) has been undertaken. Detail of hydraulic sections of water courses at Brugnato (left) and Memole (right) Hyetogram and cumulated rainfall at Brugnato – Borghetto Vara. (Source: ARPAL)
Loading Preview
Sorry, preview is currently unavailable. You can download the paper by clicking the button above.