Challenges in rockfall modelling in active tourism gorges: The case study of Caminito del Rey (Malaga, Spain)

Rockfall modelling in Caminito del Rey (Málaga, Spain) represents a scientific and technical challenge due to the high geomorphological complexity of the environment, characterized by vertical cliffs, numerous overhangs, and complex geometries. In this context, within one of Malaga’s most visited tourist attractions (more than 300,000 people per year), a comprehensive study was required to address challenges across all phases, from the detailed characterization of the inventory to trajectory modelling. To address these difficulties, the most advanced technology currently available for remote data adquisitation (UAV, LIDAR and satellite) and three-dimensional modelling was used, along with the development and application of ad hoc methods and techniques specifically tailored to this study.

The high-precision georeferenced digital rockfall inventory had to tackle issues such as data heterogeneity, limitations in the available documentation, and errors related to mapping accuracy of the trail layout. On the other hand, the modelling process required a multiscale approach, examining all sections of Caminito del Rey with a focus on detailed scales for individual blocks. Custom input data were obtained for this purpose: (i) elevation models accounting for overhangs and both gorge walls; (ii) source areas for rockfalls derived using probabilistic approaches; (iii) block size estimation based on lithology type; and (iv) calibration and validation of the three coefficients maps in narrow and vertical sections (i.e., dynamic rolling friction, normal energy restitution, and tangential energy restitution) that simulate energy loss by a boulder when rolling and bouncing at impact points.

Reducing uncertainty in each input dataset is essential not only for improving the reliability and accuracy of analytical models but also for effectively establishing preventive measures. Furthermore, it plays a key role in identifying critical areas that require continuous monitoring. This abstract was supported by the KINGSTONE project, the Rockfall Susceptibility Study in Caminito del Rey (a collaboration among IGME-CSIC, the University of Granada, the University of Jaén, and the Caminito del Rey UTE), and the SARAI project (PID2020-116540RB-C21), funded by MCIN/AEI/10.13039/501100011033.