Terraced landscapes are important to the cultural and environmental characteristics of many regions worldwide. Accurate and comprehensive documentation of these landscapes is challenging, especially ...when inventorying dry-stone walled terraced landscapes and abandoned agricultural terraces. Even inventory methods based on LIDAR and fieldwork do not capture all of the mapped information. To address this challenge, the study proposed the inclusion of additional data sources into the inventory process, specifically aerial photographs from drones and photographs taken with advanced GPS devices. The combination of already-tested methods and other data sources enabled a more comprehensive and accurate inventory process. The improved methodology was tested in three cadastral municipalities of the Vipava Valley (Črniče, Gojače and Vrtovin), where the terraces have predominantly dry-stone risers with different heights. A large percentage of the terraced landscape in the selected cadastral municipalities is abandoned, so the terraced structures are overgrown by vegetation and forest; in Gojače, almost half of the terraced landscape is like this. In some places, the terraced landscape has become almost completely unrecognizable. With an improved inventory methodology, both active and abandoned agricultural terraces can be mapped.
Spatial models are an effective tool for determining potential rockfall source, transit and deposit areas. The reliability of the final rockfall modelling results depends on the quality of the input ...data, which is mostly based on the digital elevation model (DEM). The spatial resolution of the DEM holds key information about the main morphological properties of the surface, which is crucially important when modelling this kind of geomorphological phenomenon. Therefore, this article studies the influence of DEM spatial resolution on the modelling of rockfall source, transit and deposit areas. Modelling was carried out at five different DEM spatial resolutions available for Slovenia (1 m, 5 m, 12.5 m, 25 m and 100 m). Rockfall source areas were identified using a geomorphometric approach based on a high resolution DEM and a geographical information system. Rockfall transit and deposit areas were modelled using the Conefall computer program, which is designed to estimate potential rockfall risk areas. The area of study was the municipality of Vipava (107.4 km2) in Slovenia, EU. A spatial resolution of 1 m was chosen as a reference layer to which all modelling results of the other spatial resolutions were compared. Validation of modelling included rockfall source area comparison with orthorectified aerial images and location collection of silent witnesses (rock deposits) in the field for estimating maximum runout zones. The modelling results indicate that a spatial resolution of 1 m is the most suitable for modelling on a local scale; resolutions of 5, 12.5 and 25 m can be used for modelling on a regional scale (depending on the purpose of the modelling results); and a resolution of 100 m should not be used for rockfall modelling. Major differences between spatial resolutions can be observed when modelling rockfall source areas, i.e. in areas with the most diverse topography, while in deposit areas the observed differences are smaller due to the less rugged surface.
•The influence of the spatial resolution of the digital elevation model was observed at five different spatial resolutions.•Deviations between modelling results are greater for rockfall source areas than for rockfall runout zones.•High spatial resolutions (1 m) should be used for modelling on a local scale.•Lower spatial resolutions (5 m, 12.5 m and 25 m) can be used for modelling on a regional scale.•Spatial resolution 100 m should not be used for modelling rockfalls.
The article presents the results of the analysis of low flows at 5 gauging stations on the Vipava River, which has a Dinaric pluvial-nival regime (catchment area of 590 km2). The low-flow statistics ...show that the gauging station Vipava stands out with the lowest values. Baseflow index (BFI) values are comparable among the considered stations and are around 0.40. Relatively low BFI values indicate low soil permeability. A high similarity between the mean annual minimum 7-day flow (MAM7) and the 95th percentile exceedance discharge (Q95) at all gauging stations indicates a temperate climate. The highest flows values occur in spring and autumn, and the lowest in summer. In wet years there are relatively large fluctuations in flow, while in dry years the flow consists mainly of baseflow. This is also confirmed with the flow duration curves analysis. The seasonality analysis shows a predominant summer regime with low flows.
Hillshaded digital elevation models are a well-known information layer used to determine the geomorphological properties of landslides. However, their use is limited because the results are dependent ...on a particular sun azimuth and elevation. Approaches proposed to overcome this bias include positive openness, sky-view factor, red relief image maps, and prismatic openness. We propose an upgrade to all these methods, a method named Visualization for Archaeological Topography (VAT). The method is based on a fusion of four information layers into a single image (hillshaded terrain, slope, positive openness, and sky-view factor). VAT can be used to enhance visibility of features of varied scale, height, orientation, and form that sit on terrain ranging from extremely flat to very steep. Besides this, the merits of VAT are that the results are comparable across diverse geographical areas. We have successfully tested the method for landslide recognition and analysis in five different areas in the Vipava Valley (SW Slovenia). Geomorphology of the area is very diverse and holds various types of mass movements. In contrast to classical hillshaded digital elevation models (DEMs), the geomorphological features of landslides obtained by the VAT method are very clearly seen in all studied mass movements.
The analysis of high resolution airborne lidar topography represents an essential tool for the geomorphological investigation of surface features. Here we present a detailed lidar-based ...geomorphological analysis of the ravines cut into the slopes of the upper Vipava valley, NW Slovenia. The NE slopes are defined by an Oligocene thrust-front of Mesozoic carbonates overthrusted on Tertiary flysch and covered by numerous fan-shaped Quaternary gravity flows, deposited in palaeo-ravines cut into the flysch base rock. In contrast, the opposite SW slopes are composed solely of flysch. The large dextral-slip Vipava fault extending in the NW–SE direction is present in the central part of the valley. Our research revealed that although the ravines on both slopes of the Vipava valley are lithologically and tectonically controlled, significant statistical differences in their directions exist. Thus, ravines on opposite slopes are not solely related to the Vipava fault system deformation, but instead reflect a more complex tectonic setting. We believe that the ravines are controlled by second-order faults and fault zones that connect the Vipava fault with adjacent faults. On the SW slopes, these include connecting faults between the Vipava and the southwestern Raša fault, with the ravines on the NE slopes formed in fault zones connecting the Vipava and northeastern Predjama faults.
•Lidar is an essential tool for estimated ravines in different lithological basis.•The fractured zones functioned as a narrow channel and direct debris-flow path.•Ravines in the Upper Vipava valley controlled by second-order faults
The Post-Forum Study Tour following the 4th World Landslide Forum 2017 in Ljubljana (Slovenia) focuses on the variety of landslide forms in Slovenia and its immediate NW surroundings, and the ...best-known examples of devastating landslides induced by rainfall or earthquakes. They differ in complexity of the both surrounding area and of the particular geological, structural and geotechnical features. Many of the landslides of the Study Tour are characterized by huge volumes and high velocity at the time of activation or development in the debris flow. In addition, to the damage to buildings, the lives of hundreds of people are also endangered; human casualties occur. On the first day, we will observe complex Pleistocene to recent landslides related to the Mesozoic carbonates thrust over folded and tectonically fractured Tertiary siliciclastic flysch in the Vipava Valley (SW Slovenia), serving as the main passage between the Friulian lowland and central Slovenia, and thus also an important corridor connecting Northern Italy to Central Europe. A combination of unfavourable geological conditions and intense short or prolonged rainfall periods leads to the formation of different types of complex landslides, from large-scale deep-seated rotational and translational slides to shallow landslides, slumps and sediment gravity flows in the form of debris or mudflows. The second day of the study tour will be held in the Soča River Valley located in NW Slovenia close to the border with Italy, where the most catastrophic Stože landslide in Slovenia recently caused the deaths of seven people, and the nearby Strug landslide, which is a combination of rockfall, landslide and debris flow. The final day of the Post-Forum Study Tour will start in the Valcanale Valley located across the border between Slovenia and Italy, severely affected by a debris flow in August 2003. The flow caused the deaths of two people, damaged 260 buildings; large amounts of deposits blocked the A23 Highway, covering both lanes. In Carinthia (Austria), about 25 km west of Villach, the Dobrač/Dobratsch multiple scarps of prehistoric and historic rockslides will be observed. Dobratsch is a massive mountain ridge with a length of 17 km and a width of 6 km, characterized by steep rocky walls. The 3-day study tour will conclude with a presentation of the Potoška planina landslide, a slide whose lower part may eventually generate a debris flow and therefore represents a hazard for the inhabitants and for the infrastructure within or near the village of Koroška Bela.
A method that gives the clearest individual geomorphometric elements for the requirements of spatial analysis was selected to define the spatial variability of landforms on primary bedrocks and their ...slope deposits on the northern edge of the Vipava Valley in Slovenia. We tested the most frequently used morphometric indicators of surface roughness, other than the curvature of the surface, and reviewed them based on their performance with lidar data. We analysed in detail five methods that can be used for surface roughness evaluation and that have a potential for the study of the bedrock and slope deposits. Height variability was identified as the most appropriate method. We have also found that maps of properly portrayed height variability can be an indispensable tool for geological and geomorphological mapping.
This paper is focused on SAR interferometry for deformation monitoring, based on the use of passive and active reflectors. Such reflectors are needed in all cases where a sufficient response from the ...ground is not available. In particular, the paper describes the development of a low-cost active reflector. This development was carried out in an EU H2020 project called GIMS. The paper summarizes the key characteristics of the developed active reflector. The reflector was tested in two main experiments: the first one located in the campus of CTTC and the second one in a GIMS test site located in Slovenia. The experiments demonstrate the visibility of the active reflectors and provide the first results concerning the phase stability of such devices.
In the Vipava Valley (SW Slovenia), various types of mass movements occur in a geologically and geomorphologically diverse setting. These comprise various types of landslides, creep, and Quaternary ...slope deposits of carbonate blocks and recent scree deposits. A general geological setting is represented as Mesozoic carbonate overthrust on Paleogene flysch (alternations of mostly sandstones and marlstones), resulting in steep slopes and mass movements. Our study is based on the automatic classification of various litho-geomorphological units including slope deposits, alluvial deposits, steep carbonate cliffs, flysch, two carbonate plateaus, and Quaternary deposits, based on supervised Maximum Likelihood Classification. Several polygons were used for training in the broader valley area, and later, the method was applied to automatically classify the complete area into the abovementioned six units. For input layers, we used data for elevation, slope, terrain ruggedness index (TRI), and curvature. Results show that generally, the method is suitable for classification of the litho-geomorphological units including slope deposits. However, comparison with a more detailed map, comprising mapped various mass movements indicated that the method correctly predicts high Trnovo plateau carbonates, steep carbonate slopes, translational carbonate blocks, and fossil rock avalanche deposits, and alluvial deposits, but is not able to clearly distinguish between flysch and more recent slope deposits of gravel and breccia due to their similar elevation, TRI, and slope values. The Slano blato mudflow and Stogovce landslide are not recognized. Therefore, this automatic classification can be carefully used to create a guidance map of general occurrences of litho-geomorphological units including slope deposits before going to the field, with the aim of delineation of slope deposits so they can be further studied in detail later in the field. However, such a map cannot be used as a direct substitute map for the geological and geomorphological map obtained in the field due to impossibility in distinguishing among the units with the same properties (elevation, slope, and TRI values).
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