Development of maps for assessment of landslide risk in reservoirs of major Italian dams

Federico Bonazzi¹, Fabio Oliva¹ & Massimiliano Carcione^2
1Studio Speri Società di Ingegneria S.r.l., Roma, Italia.
²Enel Green Power S.p.A., Roma, Italia.
Corresponding author e-mail: fbonazzi@sperispa.com
 

The department of “Geology Environment and Territory”, that is part of SPERI, has developed an internal methodology aimed at assessing the risk of landslides on the slopes of reservoirs for hydroelectric purposes. These dams are managed by ENEL, and distributed over 11 Italian regions. ENEL has commissioned SPERI in ATI with STUCKY to perform seismic safety checks on forty-eight large dams. Legislative rules are very detailed regarding the preliminary risk assessment related to the impulsive waves of the reservoir that can be generated by landslides for multiple causes, and instability dangerous for the functionality of deep discharges. Spatial data was processed using the QGIS software. The data used have been searched by Geoportals specific to each region of the reservoir and by national geoportals, and combined with the documentation available for each site, including any specialist studies already conducted. Once the bibliographic analysis has been conducted, its quality and degree of reliability are evaluated by performing several inspections aimed at verifying the digital data. The results of the work are represented through two graphs: (a) “Landslide Inventory Chart with geomorphological elements”, which shows all landslides catalogued in the area of interest of the reference reservoir; (b) “Thematic Maps of Analysis”, This is a table made up of three different maps, representing the use of the soil, slope and geology of the area of interest of the reservoir. This type of analysis aims to determine the potential risks between the works of the barrier and the movements of the landslide body, in case of acceleration and/ or reactivation. A detailed geomorphological analysis is performed, evaluating the parameters of each landslide body identified as volume and speed. By means of a morphometric analysis, it is possible in practice that the body has kinematics and morphological conditions of sites potentially suitable to reach the reservoir.

landslide risk, QGIS, Frane Inventory Chart, Thematic Analysis Charts, land use.