Large landslides, triggered by earthquakes or heavy rainfall, often obstruct the river’s path to form landslide dams. These phenomena can become very dangerous causing flooding both upstream, because of dam filling, and downstream, due to dam failure. In Italy, landslide dams are rather widespread along Alps and Apennines: although the identification of past events is a complex task, recently 300 landslide dams in a new open database were detected and collected (Tacconi Stefanelli et al., 2015). The present work is focused on the landslide occurred on the Bonamico River basin giving life to the Costantino Lake, nowadays completely extinct. The basin is located in the Aspromonte mountain massif (Calabria, Southern Italy) covering an area of 136 km2. The length of the main river channel is about 30 km with a mean gradient of 6% (Ergenzinger, 1992). During the night of 3 to 4 January 1973 a large landslide occurred on the slopes of Mount Costantino, in the middle of the Buonamico's mountain valley. The volume was estimated to be approximately 10-16 million m3. The mass movement caused river damming and creation of Costantino Lake. The event occurred in response to heavy rainfalls registered in 1972-1973 period, when several mass movements and widespread flooding in the regional area were counted. According to some local reports (Petrucci et al., 1996), the heavy precipitation events occurred in 1972-1973 can be considered as the exceptional weather phenomena within 1970-1980 decade, both for extreme values registered and for damages caused. The Costantino Lake, arisen immediately after landslide failure, has reached 2,400 m in length on the river bed, with a perimeter of about 5,000 m and a maximum depth of 18 m. The total volume of the lake was estimated in 7,000,000 m3. Since the river damming the water volume has steadily decreased, due to the load deposited by the river in the lake, which has raised the bottom. Due to further heavy rainfalls during 2008-2009, the Costantine Lake became extinct, 36 years after, on January 2009. The purpose of the study is to increase the knowledge on the investigated site and update the data on the evolution of the entire phenomenon taking into account information gathered both through field visits and remote sensing techniques (aerial and satellite images). Ergenzinger P. 1992. A conceptual geomorphological model for the development of a Mediterranean river basin under neotectonic stress (Buonamico basin, Calabria, Italy). In: Walling D.E., Davies T.R. & Hasholt B., Eds., Erosion, debris flows and environment in mountain regions. IAHS 209, 51-60. Petrucci O., Chiodo G. & Caloiero D. 1996. Eventi alluvionali in Calabria nel decennio 1971-1980. CNR- IRPI Cosenza. Tacconi Stefanelli C., Catani F. & Casagli N. 2015. Geomorphological investigations on landslide dams. Geoenvironmental Disasters, 2, 21.
The impact of landslide dam on a Mediterranean small basin: the case of extinct Costantino lake (Calabria, Southern Italy)
ROMEO, SAVERIO
;DI MATTEO, Lucio
2016
Abstract
Large landslides, triggered by earthquakes or heavy rainfall, often obstruct the river’s path to form landslide dams. These phenomena can become very dangerous causing flooding both upstream, because of dam filling, and downstream, due to dam failure. In Italy, landslide dams are rather widespread along Alps and Apennines: although the identification of past events is a complex task, recently 300 landslide dams in a new open database were detected and collected (Tacconi Stefanelli et al., 2015). The present work is focused on the landslide occurred on the Bonamico River basin giving life to the Costantino Lake, nowadays completely extinct. The basin is located in the Aspromonte mountain massif (Calabria, Southern Italy) covering an area of 136 km2. The length of the main river channel is about 30 km with a mean gradient of 6% (Ergenzinger, 1992). During the night of 3 to 4 January 1973 a large landslide occurred on the slopes of Mount Costantino, in the middle of the Buonamico's mountain valley. The volume was estimated to be approximately 10-16 million m3. The mass movement caused river damming and creation of Costantino Lake. The event occurred in response to heavy rainfalls registered in 1972-1973 period, when several mass movements and widespread flooding in the regional area were counted. According to some local reports (Petrucci et al., 1996), the heavy precipitation events occurred in 1972-1973 can be considered as the exceptional weather phenomena within 1970-1980 decade, both for extreme values registered and for damages caused. The Costantino Lake, arisen immediately after landslide failure, has reached 2,400 m in length on the river bed, with a perimeter of about 5,000 m and a maximum depth of 18 m. The total volume of the lake was estimated in 7,000,000 m3. Since the river damming the water volume has steadily decreased, due to the load deposited by the river in the lake, which has raised the bottom. Due to further heavy rainfalls during 2008-2009, the Costantine Lake became extinct, 36 years after, on January 2009. The purpose of the study is to increase the knowledge on the investigated site and update the data on the evolution of the entire phenomenon taking into account information gathered both through field visits and remote sensing techniques (aerial and satellite images). Ergenzinger P. 1992. A conceptual geomorphological model for the development of a Mediterranean river basin under neotectonic stress (Buonamico basin, Calabria, Italy). In: Walling D.E., Davies T.R. & Hasholt B., Eds., Erosion, debris flows and environment in mountain regions. IAHS 209, 51-60. Petrucci O., Chiodo G. & Caloiero D. 1996. Eventi alluvionali in Calabria nel decennio 1971-1980. CNR- IRPI Cosenza. Tacconi Stefanelli C., Catani F. & Casagli N. 2015. Geomorphological investigations on landslide dams. Geoenvironmental Disasters, 2, 21.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
