Long-term investigation of a deep-seated creeping landslide in crystalline rock. Part II. Mitigation measures and numerical modelling of deep drainage at Campo Vallemaggia

2007 ◽  
Vol 44 (10) ◽  
pp. 1181-1199 ◽  
Author(s):  
E. Eberhardt ◽  
L. Bonzanigo ◽  
S. Loew
Keyword(s):  
Numerical Modelling ◽  
Distinct Element ◽  
Companion Paper ◽  
Crystalline Rock ◽  
Swiss Alps ◽  
Mitigation Measures ◽  
Extensive Investigation ◽  
Deep Drainage ◽  
Measured Response

For more than 200 years, the villages of Campo Vallemaggia and Cimalmotto have been slowly moving on top of a deep-seated landslide in the southern Swiss Alps. Numerous mitigation measures have been carried out during this time to stabilize the landslide but with limited to no success. Those attempts largely focussed on minimizing erosion at the toe of the landslide. More recently, the need to stabilize the slope began to intensify, as with each passing year the two villages were being pushed closer to the edge of a 100 m high erosion front at the foot of the landslide. This led to an extensive investigation and monitoring campaign to better understand the factors controlling the landslide movements, which as reported in Part I (see companion paper, this issue), pointed to high artesian pore pressures as being the primary destabilizing mechanism. Here in Part II, the arguments supporting the need for a deep drainage solution are reported, as is the history, implementation, and measured response of the Campo Vallemaggia landslide to the various mitigative measures taken. Numerical modelling results are also presented, based on hydromechanically coupled distinct-element models, to help demonstrate why deep drainage succeeded where other mitigation measures failed.

Long-term investigation of a deep-seated creeping landslide in crystalline rock. Part I. Geological and hydromechanical factors controlling the Campo Vallemaggia landslide

2007 ◽  
Vol 44 (10) ◽  
pp. 1157-1180 ◽  
Author(s):  
L. Bonzanigo ◽  
E. Eberhardt ◽  
S. Loew
Keyword(s):  
Complex Structure ◽  
Companion Paper ◽  
Crystalline Rock ◽  
Fault Zones ◽  
Swiss Alps ◽  
Mitigation Measures ◽  
Metamorphic Rocks ◽  
Artesian Water ◽  
Creep Deformations

Slope movements of the deep-seated Campo Vallemaggia landslide in the southern Swiss Alps have been reported for over 200 years. Surface and borehole investigations of the unstable mass reveal an up to 300 m deep complex structure incorporating 800 million cubic metres of disturbed metamorphic rocks divided into blocks along primary fault zones. An average slide velocity of approximately 5 cm/year can be calculated from various monitoring data recorded between 1892 and 1995. Block movements primarily involve mechanisms relating to multiple shear surfaces, but in cases where slide blocks are constrained by other blocks, creep deformations are observed. Borehole investigations revealed the presence of artesian water pressures, which when integrated with inclinometer and surface geodetic data, helped to provide key insights into the underlying instability mechanisms. This paper reports the findings of an extensive mapping, geophysical, and monitoring investigation carried out over a 20 year period. Results from the analysis are presented with respect to the hydromechanical factors controlling the unstable mass, the significance of which were instrumental in resolving conflicts with regards to the slope mitigation measures required to stabilize the slope. In Part II (see companion paper, this issue), the stabilization works performed at Campo Vallemaggia and their effectiveness are presented.

Long-term lahar reconstruction in Jamapa Gorge, Pico de Orizaba (Mexico) based on botanical evidence and numerical modelling

Landslides ◽  
2021 ◽  
Author(s):  
José Ernesto Figueroa-García ◽  
Osvaldo Franco-Ramos ◽  
José María Bodoque ◽  
Juan Antonio Ballesteros-Cánovas ◽  
Lorenzo Vázquez-Selem
Keyword(s):  
Numerical Modelling

Projecting conflict risk following the Shared Socioeconomic pathways: what role for water stress and climate?

2021 ◽  
Author(s):  
Sophie de Bruin ◽  
Jannis Hoch ◽  
Nina von Uexkull ◽  
Halvard Buhaug ◽  
Nico Wanders
Keyword(s):  
Climate Change ◽  
At Risk ◽  
Machine Learning Techniques ◽  
Mitigation Measures ◽  
Related Factors ◽  
Socioeconomic Impacts ◽  
Learning Techniques ◽  
The Future ◽  
Conflict Risk

<p>The socioeconomic impacts of changes in climate-related and hydrology-related factors are increasingly acknowledged to affect the on-set of violent conflict. Full consensus upon the general mechanisms linking these factors with conflict is, however, still limited. The absence of full understanding of the non-linearities between all components and the lack of sufficient data make it therefore hard to address violent conflict risk on the long-term. </p><p>Although it is neither desirable nor feasible to make exact predictions, projections are a viable means to provide insights into potential future conflict risks and uncertainties thereof. Hence, making different projections is a legitimate way to deal with and understand these uncertainties, since the construction of diverse scenarios delivers insights into possible realizations of the future.  </p><p>Through machine learning techniques, we (re)assess the major drivers of conflict for the current situation in Africa, which are then applied to project the regions-at-risk following different scenarios. The model shows to accurately reproduce observed historic patterns leading to a high ROC score of 0.91. We show that socio-economic factors are most dominant when projecting conflicts over the African continent. The projections show that there is an overall reduction in conflict risk as a result of increased economic welfare that offsets the adverse impacts of climate change and hydrologic variables. It must be noted, however, that these projections are based on current relations. In case the relations of drivers and conflict change in the future, the resulting regions-at-risk may change too.   By identifying the most prominent drivers, conflict risk mitigation measures can be tuned more accurately to reduce the direct and indirect consequences of climate change on the population in Africa. As new and improved data becomes available, the model can be updated for more robust projections of conflict risk in Africa under climate change.</p>

scholarly journals On the effect of short-term climate variability on mountain glaciers: insights from a case study

2013 ◽  
Vol 59 (217) ◽  
pp. 992-1006 ◽  
Author(s):  
Daniel Farinotti
Keyword(s):  
Climatic Variability ◽  
Swiss Alps ◽  
Ice Dynamics ◽  
Mountain Glaciers ◽  
Temperature And Precipitation ◽  
Glacier Ice ◽  
Long Term Trends ◽  
Model Set ◽  
Set Up

AbstractStudies addressing the response of glaciers to climate change have so far analyzed the effect of long-term trends in a particular set of meteorological variables only, implicitly assuming an unaltered climatic variability. Here a framework for distinguishing between year-to-year, month-to-month and day-to-day variability is proposed. Synthetically generated temperature and precipitation time series following the same long-term trend but with altered variability are then used to force an ice-dynamics model set up for Rhonegletscher, Swiss Alps. In the case of temperature, variations in the day-to-day variability are shown to have a larger effect than changes at the yearly scale, while in the case of precipitation, variability changes are assessed as having negligible impact. A first set of scenarios is used to show that compared to reference, doubling the temperature variability can reduce glacier ice volume by up to 64% within half a decade. A second set derived from the results of the European ENSEMBLES project, however, shows that such changes are expected to remain below 8% even for extreme scenarios. Although the latter results relativize the importance of the effect in the near future, the analyses indicate that at least caution is required when assuming ‘unchanged variability’.

scholarly journals Addressing fish-passage issues at hydropower and irrigation infrastructure projects in Indonesia

2018 ◽  
Vol 69 (12) ◽  
pp. 1805 ◽  
Author(s):  
Lee J. Baumgartner ◽  
Arif Wibowo
Keyword(s):  
Life History ◽  
Fish Passage ◽  
Mitigation Measures ◽  
Migratory Fish ◽  
Tropical Island ◽  
Life History Stages ◽  
Barrier Effects ◽  
Sumatra Island ◽  
Irrigation Infrastructure

Development activities threaten the long-term sustainability of tropical floodplain systems. The construction of dams, weirs, irrigation infrastructure and regulators affect connectivity among habitats and can facilitate rapid declines in riverine biota, especially fish. Indonesia is a tropical island country with an abundance of monsoonal rivers. Massive expansions in hydropower and irrigation infrastructure are planned over the next two decades and mitigation measures will be needed to protect migratory fish. Most Indonesian freshwater fish need to migrate among habitats to complete essential life-history stages. So, strategies are urgently needed to mitigate the barrier effects of river infrastructure to ensure the long-term sustainability of river fishes. A common tool used worldwide is the construction of upstream and downstream fish passes. Only two fish passes exist in Indonesia. One at Perjaya Irrigation Dam on the Komering River (Sumatra island) and another on Poso Dam on the Poso River (Sulawesi island). Neither of these structures has been assessed and many other projects are proceeding without considering potential impacts on fisheries. The proposed infrastructure upgrades over the next two decades provide a once-in-a-generation opportunity to ensure that migratory fish are adequately protected into the future.

scholarly journals The role of frost cracking in local denudation of steep Alpine rockwalls over millennia (Eiger, Switzerland)

2020 ◽  
Vol 8 (3) ◽  
pp. 637-659
Author(s):  
David Mair ◽  
Alessandro Lechmann ◽  
Romain Delunel ◽  
Serdar Yeşilyurt ◽  
Dmitry Tikhomirov ◽  
...  
Keyword(s):  
Swiss Alps ◽  
Rock Fall ◽  
Temperature Changes ◽  
Rock Face ◽  
Temperature Conditions ◽  
Denudation Rates ◽  
Reconstructed Temperature ◽  
Cryogenic Processes

Abstract. Denudation of steep rockwalls is driven by rock fall processes of various sizes and magnitudes. Rockwalls are sensitive to temperature changes mainly because thermo-cryogenic processes weaken bedrock through fracturing, which can precondition the occurrence of rock fall. However, it is still unclear how the fracturing of rock together with cryogenic processes impacts the denudation processes operating on steep rockwalls. In this study, we link data on long-term rockwall denudation rates at the Eiger (Central Swiss Alps) with the local bedrock fabric and the reconstructed temperature conditions at these sites, which depend on the insolation pattern. We then estimate the probability of bedrock for failure through the employment of a theoretical frost cracking model. The results show that the denudation rates are low in the upper part of the NW rockwall, but they are high both in the lower part of the NW rockwall and on the SE face, despite similar bedrock fabric conditions. The frost cracking model predicts a large difference in cracking intensity from ice segregation where the inferred efficiency is low in the upper part of the NW rockwall but relatively large on the lower section of the NW wall and on the SE rock face of the Eiger. We explain this pattern by the differences in insolation and temperature conditions at these sites. Throughout the last millennium, temperatures in bedrock have been very similar to the present. These data thus suggest the occurrence of large contrasts in microclimate between the NW and SE walls of the Eiger, conditioned by differences in insolation. We use these contrasts to explain the relatively low denudation rates in the upper part of the NW rockwall and the rapid denudation in the SW face and in the lower part of the NW rock face where frost cracking is more efficient.

scholarly journals Numerical Modelling of Waves and Surge from Cyclone Mekunu (May 2018) in the Arabian Sea

2020 ◽  
Vol 2 (4) ◽  
Author(s):  
M. A. Sarker
Keyword(s):  
Numerical Modelling ◽  
Arabian Sea ◽  
Significant Loss ◽  
Mitigation Measures ◽  
Wave Transformation ◽  
Marine Structures ◽  
Loss Of Life ◽  
The Public ◽  
Risk Reduction Measures ◽  
Set Up

Natural hazards like cyclones cause significant loss of life and damage to properties, ecosystems and marine structures and facilities. Numerical modelling of cyclones is carried out for deriving robust design conditions for coastal and marine structures and facilities. Cyclone modelling results are also used for emergency planning and decision-making to estimate potential loss of life, damage to properties and marine facilities and to develop rescue and mitigation measures and plan clean-up operations. Royal HaskoningDHV (RHDHV) has set up regional tidal hydrodynamic and wave transformation models covering the Arabian Sea to address the above issues. Cyclone Mekunu is relatively new (May 2018). A quick literature search by Royal HaskoningDHV has suggested that numerical modelling results of waves and surge on Cyclone Mekunu are hardly available in the public domain. Therefore, this paper has concentrated on this event to illustrate the use of numerical modelling to simulate waves and surge generated by cyclones. The MIKE21 model of DHI was used in the study. Sample results of waves and surge from the modelling study are presented in this paper for illustration purposes. Structural design considerations and cyclone risk reduction measures are also provided. The model could be used to simulate any cyclone generated anywhere within the Arabian Sea. The methodology described in this paper for modelling cyclone waves and surge in the Arabian Sea could also be applied to simulate cyclones at other sites around the world. The paper provides valuable information to the researchers and practitioners of the region on this relatively new event.

scholarly journals Autogenic versus allogenic controls on the evolution of a coupled fluvial megafan/mountainous catchment system: numerical modelling and comparison with the Lannemezan megafan system (Northern Pyrenees, France)

2016 ◽  
Author(s):  
Margaux Mouchené ◽  
Peter van der Beek ◽  
Sébastien Carretier ◽  
Frédéric Mouthereau
Keyword(s):  
Numerical Modelling ◽  
Temporal Variations ◽  
Tectonic Activity ◽  
Mountain Range ◽  
Stream Network ◽  
Mountainous Catchment ◽  
Isostatic Rebound ◽  
Base Level ◽  
Alluvial Terraces

Abstract. Alluvial megafans are sensitive recorders of landscape evolution, controlled by autogenic processes and allogenic forcing and influenced by the coupled dynamics of the fan with its mountainous catchment. The Lannemezan megafan in the northern Pyrenean foreland was abandoned by its mountainous feeder stream during the Quaternary and subsequently incised, leaving a flight of alluvial terraces along the stream network. We explore the relative roles of autogenic processes and external forcing in the building, abandonment and incision of a foreland megafan using numerical modelling and compare the results with the inferred evolution of the Lannemezan megafan. Autogenic processes are sufficient to explain the building of a megafan and the long-term entrenchment of its feeding river at time and space scales that match the Lannemezan setting. Climate, through temporal variations in precipitation rate, may have played a role in the episodic pattern of incision at a shorter time-scale. In contrast, base-level changes, tectonic activity in the mountain range or tilting of the foreland through flexural isostatic rebound appear unimportant.

scholarly journals Heterogeneous Mental Health Development During the COVID-19 Pandemic in the United Kingdom

2021 ◽  
Author(s):  
Lea Ellwardt ◽  
Patrick Praeg
Keyword(s):  
United Kingdom ◽  
Psychological Distress ◽  
Latent Class ◽  
Mitigation Measures ◽  
Social Lives ◽  
The United Kingdom ◽  
Policy Measures ◽  
Nationally Representative ◽  
The Uk

Aim. The COVID-19 pandemic and the mitigation measures by governments have upended the economic and social lives of many, leading to widespread psychological distress. However, how distress developed during the pandemic and who was most affected is poorly understood. We explore heterogeneity in trajectories of psychological distress during the first six months of the pandemic in the United Kingdom and relate this heterogeneity to socio-demographic and health factors. Subjects and Methods. We analyze six waves of longitudinal, nationally representative survey data from the UK Household Longitudinal Study (N = 15,218), covering the first lockdown in 2020. First, latent class mixture modelling (LCCM) is used to identify trajectories of psychological distress. Second, associations of the trajectories with covariates are tested with multinomial logistic regressions. Results. We find four different trajectories of distress: continuously low, continuously moderate, temporarily elevated, and continuously elevated distress. One-fifth of the population experienced severely elevated risks of distress. Long-term exposure was highest among younger people, women, those who lost income, and those with previous health conditions or COVID-19 symptoms. Conclusion. Given the threat of persistent stress on health, policy measures should be sensitized to the unintended yet far-reaching consequences of non-pharmaceutical interventions.

Sign in / Sign up

Export Citation Format

Share Document