Responses of salmonids to habitat changes

Streams in western North America provide spawning and rearing habitats for several species of salmon and trout that are of substantial economic importance in the region. Timber that grows on lands through which these streams flow is also economically important, and its harvest can substantially change habitat conditions and aquatic production in salmonid streams. Undisturbed forests, the streams that flow through them, and the salmonid communities in these streams have intrinsic scientific, genetic, and cultural values in addition to their economic importance. The complex relations between salmonids and their physical environment, and the changes in these relations brought about by timber harvest, have been investigated extensively (see the bibliography by Macdonald et al. 1988). However, in spite of considerable evidence of profound changes in channel morphology and in light, temperature, and flow regimes associated with timber harvests, much uncertainty exists about the responses of salmonids to these changes

Rockfall occurrence and fragmentation

Rockfalls are very rapid and damaging slope instability processes that affect mountainous regions, coastal cliffs and slope cuts. This contribution focuses on fragmental rockfalls in which the moving particles, particularly the largest ones, propagate following independent paths with little interaction among them. The prediction of the occurrence and frequency of the rockfalls has benefited by the rapid development of the techniques for the detection and the remote acquisition of the rock mass surface features such as the 3D laser scanner and the digital photogrammetry. These techniques are also used to monitor the deformation experienced by the rock mass before failure. The quantitative analysis of the fragmental rockfalls is a useful approach to assess risk and for the design of both stabilization and protection measures. The analysis of rockfalls must consider not only the frequency and magnitude of the potential events but also the fragmentation of the detached rock mass. The latter is a crucial issue as it affects the number, size and the velocity of the individual rock blocks. Several case studies of the application of the remote acquisition techniques for determining the size and frequency of rockfall events and their fragmentation are presented. The extrapolation of the magnitude-frequency relationships is discussed as well as the role of the geological factors for constraining the size of the largest detachable mass from a cliff. Finally, the performance of a fractal fragmentation model for rockfalls is also discussed.Peer ReviewedPostprint (published version

Landslide Mapping in Austria

Landslides are a major natural hazard in hilly and mountainous regions of Austria. The delineation and characterisation of landslide hazard areas in the whole country using a harmonized approach is of the utmost importance to the implementation of risk reduction strategies, including also land use planning and mitigation measures, as suggested in the EU Thematic Strategy for Soil Protection. To this end, a study of landslide maps and ancillary data available mainly at national and regional (federal state) mapping organisations and research institutes in Austria has been carried out. The results show that, although not exhaustive, a great deal of information on landslides exists in Austria. Such information is mainly available in the form of landslide inventories and susceptibility maps, often making part of digital databases. These data are however widely spread in different administrations, mainly because of the federal structure of the country. Primarily as a result of this, these maps and databases show significant differences concerning the mapping approach used, landslide classification criteria, representation scale, legend and symbology, data format, etc. Accessibility to most of these data is at the moment restricted to public administrations, although there are currently initiatives to make them publicly accessible via webGIS. Finally, some recommendations to improve landslide risk management in the country are provided.JRC.H.7-Land management and natural hazard

Analysis of rockfalls by means of a fractal fragmentation model

The final publication is available at Springer via http://dx.doi.org/10.1007/s00603-019-01987-2We present the performance of the rockfall fractal fragmentation model (RFFM) developed by Ruiz-Carulla et al. (Landslides 14(3):875–889. doi.org/10.1007/s10346-016-0773-8, 2017) and based on Perfect (Eng Geol 48:185–198, 1997). The RFFM combines disaggregation of the initial rock mass and breakage of the blocks. The model has been upgraded as to meet the mass balance, and to generate both a continuous decreasing and scale variant distribution of fragments volumes. The input of the model may be either a single block or a rock mass characterized by its In situ Block Size Distribution (IBSD). The measured fragment size distributions of seven inventoried rockfall events are used to calibrate the model. The results of the simulations fit well to the measured volume distributions. Our findings indicate that fragmentation is better characterized by the whole volume distribution of fragments generated and the increase of new surface area of the rock fragments. A relation has been observed between the potential energy of the first impact, the new surface area of fragments generated, and the model parameters. Although a greater number of parametric analyses and calibration exercises are required, this relation is proposed as a first approach to model rockfall scenarios.Peer ReviewedPostprint (author's final draft

Chapter 6 Living with landslides for Landslide Ecology

1. Human interactions with landslides have become more frequent and lethal as our populations expand into less stable terrain. This trend suggests that we must better understand what causes landslides and how to mitigate future damage. 2. Disturbances created by road construction, urban expansion, forestry, and agriculture are major contributors to anthropogenic landslides, and each has increased in frequency during the last several decades. 3. The field of landslide risk assessment is growing rapidly, and many new mapping and modeling tools are addressing how to predict landslide frequency and severity. Mitigation of landslide damage is also improving, particularly when new landslides follow patterns similar to previous ones. Despite a broad understanding oflandslide triggers and consequences, detailed predictions of specific events remain elusive, due to the stochastic nature of each landslide\u27s timing, pathway, and severity. 4. Biological tools are valuable additions to efforts to mitigate landslide damage. Biological protection of soil on slopes and restoration of species composition, food webs, and ecosystem processes ultimately must supplement technological approaches to achieve long-term slope stability because biological systems are generally more resilient than man-made structures

Development of Harmonized Indicators and Estimation Procedures for Forests with Protective Functions against Natural Hazards in the Alpine Space

The present study was developed in the context of Regulation (EC) 2152/2003 on the monitoring of forest and environmental interactions, the so-called "Forest Focus" Regulation. The specific objective of this study was to explore the possible contribution of the national forest inventories (NFIs) to assess protective functions of for-ests in the alpine space. Key components of protective functions could be determined with the help of on-going national and international studies and processes. In order to grant consistency, definitions of forest area, dam-age potential and hazard potential had to be harmonised. Based on those, a strategy for monitoring and report-ing aspects of protective functions of mountain forests in the alpine space was proposed. Estimation procedures based on existing NFI data and field assessments and their integration in different remote sensing techniques were tested for harmonised monitoring. Final results are presented in this report.JRC.DDG.H.7-Land management and natural hazard

Reinforcement design and control of rock slopes above tunnel portals in Northern Italy

The stability features of slopes located above the portals of tunnels along important roads are here presented, together with two examples for reinforcement and protection works. The investigation phase and the reinforcement works have considered also the purpose of avoiding the interruption of the traffic when this would cause unacceptable consequences. The first case refers about the construction of a portal along a narrow and steep valley in a volcanick rock formation. The control of the vibration of the blasting action has been carried out for the period of the excavation in order to foresee the occurrence of potential dangerous situations. The second is the case of the portal of the East access to the Highway n.10. Even though the adits are protected by two portals, the occurrence of rock and debris falls from the upper part of the mountain could create a dangerous situation. Above the portals the morphology of the slope is characterized by two subvertical rock slopes, which are separated by an intermediate zone of debris material

Tree-ring based reconstruction of past snow avalanches using two tree species at a slope in the Göscheneralp

Snow avalanches pose a major threat to people living in mountainous regions across the world. Chronologies of such events date back centuries and are often focused on larger events and substantial damage to people and infrastructure. Dendrochronology offers methods to reconstruct snow avalanches at a specific site, when no records are available. In this thesis, silver birch (Betula Pendula Roth) and mountain pine (Pinus mugo Turra) were used in order to reconstruct snow avalanches at a site at the Göscheneralp, Uri. For this purpose, increment cores and discs were extracted and thin sections produced. Event dating was done by means of an eccentricity analysis as well as compression wood findings. Furthermore, the findings were compared to an existing snow avalanche chronology. As a result, snow avalanches were determined to have happened in years 1999, 2008, 2010, 2012, 2019 and 2021. In addition, snow avalanches were also spatially defined. The findings serve as a reasonable approximation, however should not be taken unambiguously

Landslide hazard zonation of slopes susceptible to rock falls and topples

International audienceA landslide hazard zonation is a division of the land surface into areas, and the relative ranking of these areas according to degrees of actual or potential hazard from landslides on slopes. Zonation from scientific research does not generally imply legal restrictions, but can be useful to those people who are charged with the land management, by providing them with information that is indispensable for planning and regulation purposes. This paper presents a zonation of rock slopes in carbonate mountains on the boundary to the east of the valley of the Sele River (Campania, southern Apennines of Italy). The mountains are severely affected by rock falls and topples, and the related hazard is, therefore, very high; the presence of inhabited areas (the towns of Valva, Colliano and Collianello) and other human infrastructures at the slope foothills make these phenomena extremely dangerous to the anthropogenic environment. The area is highly seismic, as experienced on the occasion of several moderate to strong earthquakes that have hit this sector of the Apennines. According to the zonation proposed here, the ridge of Mount Valva and Mount Marzano is subdivided into four main areas on the basis of the processes which take place in the different sectors of the mountains: the source area, the talus slope, the rockfall shadow (where scattered outlying boulders are present), and the safe area (outside of the reach of fallen blocks). The four sectors were identified through air-photo interpretation and detailed field surveys, aimed in particular at characterizing and interpreting the main rock mass joint patterns, and their relative orientation with respect to the local slope direction. Geological, morphological and structural analyses permitted one to evaluate and classify those parts of the slope that are more susceptible to detachment of rocks, and to identify the more diffuse types of failure. Due to high seismicity of the study area, particular attention was given to the evaluation of the seismic susceptibility to rock falls, by applying two methods recently proposed in literature. Results from this phase of the study were then integrated by additional information from historical research on slope movements occurred previously in the area. The landslide hazard zonation, shown on large-scale cartography, could be compared to maps depicting the distribution and typology of the anthropogenic activities, and thus constitutes a useful tool for administrators and planners, in order to evaluate the hazards related to slope movements, and the vulnerability of settlements, roads, and other man-made infrastructures