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Soil erosion processes are a type of geological hazard. They cause soil loss and sediment production, landscape dissection, and economic damage, which can, in the long term, result in land abandonment. Thus, identification of soil erosion processes is necessary for sustainable land management in an area. This study presents the potential of visual interpretation of high resolution LiDAR (light detection and ranging) imagery for direct and unambiguous identification and mapping of soil erosion processes, which was tested in the study area of the Vinodol Valley (64.57 km2), in Croatia. Eight LiDAR images were derived from the 1 m airborne LiDAR DTM (Digital Terrain Model) and were used to identify and map gully erosion, sheet erosion, and the combined effect of rill and sheet erosion, with the ultimate purpose to create a historical erosion inventory. The two-step procedure in a visual interpretation of LiDAR imagery was performed: preliminary and detailed. In the preliminary step, possibilities and limitations for unambiguous identification of the soil erosion processes were determined for representative portions of the study area, and the exclusive criteria for the accurate and precise manual delineation of different types of erosion phenomena were established. In the detailed step, the findings from the preliminary step were used to map the soil erosion phenomena in the entire studied area. Results determined the highest potential for direct identification and mapping of the gully erosion phenomena. A total of 236 gullies were identified and precisely delineated, although most of them were previously unknown, due to the lack of previous investigations on soil erosion processes in the study area. On the other hand, the used method was proven to be inapplicable for direct identification and accurate mapping of the sheet erosion. Sheet erosion, however, could have been indirectly identified on certain LiDAR imagery, based on recognition of colluvial deposits accumulated at the foot of the eroded slopes. Furthermore, the findings of this study present which of the used LiDAR imagery, and what features of the imagery used, are most effective for identification and mapping of different types of erosion processes.

Monitoring is important for assessing the stability of the ground and for confirming the validity of the design during the construction and operation of structures. The ideal monitoring system for projects in Rock and Geotechnical Engineering would be able to monitor the behavior of small to extensive areas continuously and automatically with high accuracy. In addition, the costs would be low and the system would be easy to handle. Satellite technology has the potential to realize the above monitoring system by combining it with conventional geotechnical instruments. In this paper, satellite technology for displacement monitoring, i.e., GPS and SAR, is firstly outlined and then the concept of spatiotemporal continuous displacement monitoring is introduced. The use of both satellite technology and geotechnical instruments is effective for geotechnical monitoring. Practical applications of GPS for landslide monitoring and collaborative researches using DInSAR with Balkan countries are described.

In this paper scientific activities of the Croatian Landslide Group (CLG), World Centre of Excellence on Landslide Risk Reduction (WCoE) of the International Consortium on Landslide (ICL) for the period 2014-2017, are shortly described. The results of scientific research are presented through the fields of landslide science: landslide identification and mapping, landslide investigation and testing, landslide monitoring, landslide modelling and landslide stabilization and remediation. It is concluded that the resulting landslide inventory maps, regional empirical rainfall intensity-duration thresholds, kinematic landslide models and soil strength parameters, landslide movement prediction models, numerical models and simulations and behavior of geotechnical construction for landslide stabilization provide necessary information for landslide risk management in Croatia. Besides applied scientific research, the general objectives of ICL WCoE are achieved in the framework of two Croatian IPL Projects and regional ICL Adriatic-Balkan Network.

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