Possible Scenarios for Rjecina River Catchment -on the Example of Grohovo Landslide

Synopsis R jecina river is an example of a large torrential watercourse typical for the coastal karst zone of Croatia with its river mouthin the center of Rijeka city. The central part of the watercourse is the most unstable part of the valley, with the highest degree of geological hazard. Here, mass movementsare occurring mainly at the contact of carbonate rockswith the flyschrock complex. There are historic data of few rockfallsand landslides on both slopes of the valley. A potential geohazardevent could involve movement of slope deposits towards the channel of the Rjecina River. Heavy precipitation and/or earthquakes may be potential triggers of rockfallsand rockslides. So there is a possibility of massive scale landslide occurrence and consequently it can cause several scenarios. Possible scenarios would be investigated furtherly during the Croatia-Japan Joint Project. The paper shows the basic modeling approach for Scenario for Massive scale debris flowoccurrence.