Author(s): Cristina Reyes-Carmona; Jorge Pedro Galve; Anna Barra; Marcos Moreno-Sanchez; Oriol Monserrat; Adrian Riquelme; Teresa Teixido; Patricia Ruano; Agustin Millares; Roberto Sarro; Jose Vicente Perez-Pena; Pablo Ezquerro; Juan Lopez-Vinielles; Marta Bejar-Pizarro; Jose Miguel Azanon; Rosa Maria Mateos

Linked Author(s): Cristina Reyes-carmona, Agustín Millares

Keywords: Landslides; Monitoring; InSAR; Reservoir safety

Abstract: Unstable slopes in critical infrastructures such as reservoirs usually lead to risky situations that may entail a large amount of material, economic and even human losses. Remote Sensing techniques have proven to be very useful tools to avoid or minimize these disasters. One of these techniques is satellite radar interferometry (InSAR), which is capable of detecting millimetre movements of the ground at a high spatial and temporal resolution. Using this technique, we have detected three active landslides within the slopes of the Rules Reservoir: the Lorenzo-1 Landslide, the Rules Viaduct Landslide and the El Arrecife Landslide. The first two are rotational landslides (surface of rupture is curved) and they are affecting the N-323 National Road and the southern abutment of the Rules Viaduct (Highway A-44), respectively. The InSAR displacement rates are up to 2 cm/yr for the Lorenzo-1 Landslide and up to 2.5 cm/yr for the Rules Viaduct Landslide. Furthermore, the displacement patterns of both landslides show a correlation with changes in the water level of the reservoir: the movement is accelerated with declines of the water level of the reservoir. On the other hand, the El Arrecife Landslide has a translational character (the surface of rupture is planar) and therefore, it presents a potential hazard of experiencing a critical acceleration and a partial or total rupture of the slope. This would generate a collapse of a slide mass into the reservoir, what would have devastating consequences (for example, a massive flash flood downstream). Using InSAR and geophysical techniques (Ground Penetrating Radar), we detected a vertical movement of around 2 cm/yr along the N-323 National Road, being up to 6 cm/yr at the foot of the landslide. As the other landslides, the movement of the El Arrecife Landslide foot is accelerated with the reservoir water level declines. We have also performed a detailed geological study that made possible to preliminary estimate the volume of the landslide: 14.7 million m3. With the data presented, we provide a first view of the nature of these landslides and the hazard that they imply to the Rules Reservoir. Having done this, we consider essential to develop a remote and in-situ monitoring system of the activity of these landslides. In such way, possible pre-failure precursors of a rapid acceleration could be identified far enough in advance to avoid irreversible damages in the reservoir and related infrastructures (as the Rules Dam, the N-323 National Road, the Rules Viaduct and the A-44 Highway). A continuous monitoring of the landslides is the key to conduct to a suitable and safe management of the reservoir, especially for water discharges

DOI: https://doi.org/10.3850/IAHR-39WC2521711920221384

Year: 2022