Naslov
The hazard of floods and mass movements in the Rjecina Valley (Croatia) during last 160 years

Autori
Vivoda, Martina ; Đomlija, Petra ; Dugonjić Jovančević, Sanja ; Podolzski, Lazslo ; Benac, Čedomir

Vrsta, podvrsta i kategorija rada
Radovi u zbornicima skupova, cjeloviti rad (in extenso), znanstveni

Izvornik
2nd Project Workshop of the Croatia - Japan Project on Risk Identification and Land-use Planning for Disaster Mitigation of Landslides and Floods in Croatia "Monitoring and analyses for disaster mitigation of landslides, debris flow and floods" : book of proceedings / Ožanić, Nevenka ; Arbanas, Željko ; Mihalić, Snježana ; Marui, Hideaki ; Dragičević, Nevena - Rijeka : Sveučilište u Rijeci, 2012, 114-117

ISBN
978-953-6953-30-1

Skup
Project Workshop of the Croatia - Japan Project on Risk Identification and Land--use Planning for Disaster Mitigation of Landslides and Floods in Croatia (2 ; 2011)

Mjesto i datum
Rijeka, Hrvatska, 15.11.2011. - 17.11.2011

Vrsta sudjelovanja
Predavanje

Vrsta recenzije
Međunarodna recenzija

Ključne riječi
flood; mass movement; erosion; landslide; overflow

Sažetak
In this paper will be described and analyzed the connection of earthquakes, floods and instabilities of slopes in the Rječina valley. The Rječina River flows through three different geomorphological zones. The first occupies the area from the river source at the foot of the Gorski kotar Mountains to the Lukeţi Village. The second zone extends from Lukeţi Village to the canyon entrance near the Pašac Bridge, while the third stretches from the entrance of the canyon and the alluvial plain near the river mouth in the centre of Rijeka City. The slopes around Rječina Valley between Lukeţi Village and entrance of canyon are formed in siliciclastic sedimentary rocks with flysch characteristics. The bedrock is mostly covered with unstable slope formations. A limestone rock mass is visible on the cliffs around the top of the river valley. Lateral erosion of the riverbed and simultaneous erosion of the foot of the slopes, are factors causing mass movements. Historic data for the area of Rijeka, record the occurrence of flood events, (some of which caused catastrophic damage), that are closely related to the timing of mass movements in the study area. Such catastrophic floods of the Rječina River occurred 1849, 1852, 1853, 1883, 1898 and 1899. According to data from the Croatian State Archive in Rijeka, the landslides appeared on the south-western slope in 1885 and 1898, and in 1893 on the north-eastern slope, at the location of the studied landslide. The area affected by mass movements is clearly visible on the map from 1894. Investigation of the whole area of the valley between Valići Reservoir and the downstream canyon entrance reveals the presence of more dormant landslides, some of which were active during the 20th century. The influence of river erosion was reduced after completion of the Rječina riverbed regulation in 1908. Instability on the north-east slope is due to a reactivated landslide, as shown by recorded historic activity. Frequent rockfalls from the top of the limestone cliff accelerated the accumulation of potentially unstable deposits. Topographic maps from 1981 and 1998 have shown changes in slope morphology. Observation of geodetic benchmarks from 1998 – 2010 highlighted displacements, not only in the part of the slope affected by slippage, but also the formation of a new landside body on the upper part of the slope, indicating further development of the landslide along the slope. The infilling and therefore damming of the Rječina River is the main risk of further sliding. In a case of heavy rainfall, accumulated water behind any such dam would be at risk of overflow, resulting in rapid water level rise and/or subsequent overflow. After such a collapse, the water wave could cause fatalities and serious damage to infrastructure in the urban area of the City of Rijeka at the mouth of the Rječina River.

Izvorni jezik
Engleski

Znanstvena područja
Geologija, Građevinarstvo, Rudarstvo, nafta i geološko inženjerstvo

Napomena
Sažetak rada ubjavljen u Knjizi sažetaka / Nevenka Ožanić, Željko Arbanas, Snježana Mihalić, Hideaki Marui (ur.) ; 2011. ; str. 39-39 ; 978-953-6953-26-4 .

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