Building objects and huseholds inventorying for the purpose of risk estimation on the Umka landslide near Belgrade

Abstract

The Umka landslide is systematically investigated and one of the biggest inhabited landslides in Serbia. Landslide is active, with known sliding intensity (more or less) for last 50 years, while landslide is old couple of hundred years, and its genesis is related with evolution of Sava meanders. Although the landslide is known and occasionally mentioned in mass media, certain migration of population is evident, so besides permanent displacement from the landslide – some new housing objects are notices with permanent residents, even within the most active and most affected part of the landslide. According to previous research, a landslide is divided into three zones (blocks) that are different by sliding depth, dynamics and by slope morphology. The last object inventorying was performed during 1989–1990 by the Highway Institute from Belgrade when the map of the damaged objects (with the type of foundation, walls, and category of object) was created, local water system was mapped, while evaluation of population was performed by last known census data. Since the last inventorying was performed 25 years ago, and a landslide is still not stabilized although project documentation for stabilization exists from that period, the vulnerability of population is still actual while in some parts it is even more intensive which is a consequence of unplanned and illegal construction works during ’60 and ’70 of XIX century, when most of objecst were built (over 250 of them).Considering above, there was a need for inventtorying of all present building objects which are within the landslide cadaster border, so such that data can be easily compared with previous research. The base for the creating new inventorying sheet was surveying sheet from 1989. New sheet contains 11 groups of question: 1) Basic data about building object 2) Data about object construction 3) Data about object deformations 4) Data about object foundation 5) Data about household 6) Damage estimation 7) Emergency and temporary interventions 8) Recovery measures 9) Data about household water, surface and groundwaters 10) Sketch of object damage 11) Other comments. Previous inventorying didn’t include the question about householdand population working and life habits which is necessary data for the risk estimation. Inventorying was carried out from September to November 2017. and more than 360 objects were evidenced with more than 500 residents. Each object was photographed and located by the coordinate of the object central point with previously written or oral permission of the resident or object owner. More than 95% of object owners and residents gave the permission for the collecting the data, while there was a lot of objects that were abandoned and which was only evidenced from the outside by construction condition. Detailed results with following statistics will be presented after the data processing that will be done by the end of the 2018 year. Inventorying was performed within the project grant no. TR36009 that is financed by Ministry of education, science and technological development of the Republic of Serbia.