Amponsah W., Borga M., Marchi L., Nikolopoulos E.I., Marra F., Crema S., M. Pirastru, Zoccatelli D, Niedda M., Marrosu R., 2014, The flash-flood of November 2013 in NE Sardinia (Italy): Post-event documentation and hydrological modelling,
8th HyMeX Workshop, La Valletta, Malta, 15-18.08.2014,
Abstract
On November 18, 2013, the North-Eastern part of Sardinia was impacted by extreme flash flooding, ...
On November 18, 2013, the North-Eastern part of Sardinia was impacted by extreme flash flooding, which killed 19 people and caused up to 1 billion Euro damage. The flooding was associated with an extratropical cyclone in the western Mediterranean Basin, named Cyclone Cleopatra, which developed slow-moving embedded thunderstorm complexes, as cold air flowing from the north entered the Mediterranean and interacted with warm moist air to the east. The impacted area is up to 1500 km2, and includes a number of basins, including the Posada ( 690 km2) and Cedrino (625 km2) basins. The cyclone brought extremely heavy rain to the area, with up to 450 mm of rain in 12 hours (from 07_00 to 19_00 local time), resulting in severe flooding. A high concentration of fatalities and damages occurred in the area around the northeastern city of Olbia, also due to high vulnerability resulting from inappropriate urbanization.
Post-flood documentation, focused on the Cedrino and Posada river systems, included the reconstruction of peak discharge by means of topographic surveys, observations on the geomorphic effects of the event both in the channel network and on hillslopes and assessment of the timing of the flood based on the accounts of eyewitnesses. Technical services of regional authorities and local administrations contributed to the documentation of the flood by providing hydrometeorological data, accounts of volunteers of the civil protection and photos taken during and immediately after the flood. The assessment of unit peak discharges confirmed the severity of the flood, with values up to approximately 10 m3s-1km-2 in catchments up to 500 km2. The strong spatial gradients of the precipitation had a major influence on flood response, with large difference in peak discharge between neighbouring catchments.
The availability of high-resolution rainfall estimates from radar observations and a rain gauge network, together with indirect peak discharge estimates from the post-event survey, provided the opportunity to study in detail the hydrometeorological and hydrological mechanisms associated with this extreme storm and the ensuing flood.
Observations and model results are combined to examine two main questions, (i) assessment of the distribution of the runoff ratio and how it is controlled by the heterogeneous geological structure; and (ii) analysis of how the spatial and temporal distribution of the extreme rainfall, and more specifically storm motion, controls the flood response.
F. Coccon, and G. Bossi, M. Borrotti, P. Franzoi, and P. Torricelli, 2014, Wildlife collisions with aircrafts_ land use around airports as a tool for decision making process and risk management to reduce the birdstrike risk.,
XXIV Congresso della Società Italiana di Ecologia, Ferrara, 2014,
Marchi Lorenzo, 2014, Dalla documentazione degli eventi alluvionali alla valutazione della pericolosità: lo studio pilota del bacino del Torrente Pogliaschina,
...che Iddio ce la mandi buona! Sappiamo davvero prevenire il rischio geo-idrologico?, Sarzana (SP), 16.05.2014,
Marchi L., Amponsah W., Borga M., Cavalli M., 2014, Stream power of recent flash floods in Europe_ data collection and analysis,
International Geographical Union Regional Conference - Changes Challenges Responsability, Krakow (Poland), 18-22 August 2014,
Abstract
Stream power is a key variable for the evolution of landforms associated to the fluvial ...
Stream power is a key variable for the evolution of landforms associated to the fluvial systems. Several studies on stream power have related to bankfull or near-bankfull discharge, which is regarded as morphologically significant. The analysis of stream power for bankfull discharges permits homogeneous comparisons of stream power between different parts of a channel network, whereas the stream power assessment for large floods provides important insights on river energy expenditure that caused major, abrupt morphological changes in channels and on floodplains.
Because of the strong spatial gradients of rainfall inputs, flash floods often hit different patterns of a river basin with different intensity. Resulting values of stream power show spatial variations that depend on geological controls on channel geometry and sediment characteristics, as well as on variations of flood intensity_ this urges a field approach that takes into account such variations of the factors that influence stream power.
Post-flood assessment of peak discharge after major floods makes it possible to analyse stream power in fluvial systems stressed by high-intensity floods. This study analyses the stream power of some extreme (return period > 100 years) flash floods that occurred in mountainous basins of various European regions in the last decade. The spatial variability of stream power is examined taking into account topographic variables, such as upstream contributing area, channel slope and cross-sectional width, and with regard to differences of flood response intensity in various sectors of the river basin.
In most of the analysed cross-sections, high values of specific stream power were observed_ this is consistent with the high severity of the studied floods. Field observations have shown that, depending on flood intensity, channel geometry and material, and sediment supply due to landslides and debris flows in the tributaries, the studied flash floods produced geomorphic changes of different intensity in alluvial channels and on floodplains.
Not surprisingly, lined channels, usually characterised by narrow width, display higher values of specific stream power than natural cross-sections draining catchments of similar size. Channel erosion in lined channels, as well as in bedrock channels, was usually negligible.
Continuing post-flood surveys by means of standardised procedures is of utmost importance for extending and updating quantitative information on flash floods in Europe. In this context, data on stream power are of great importance for linking hydrological and hydraulic characteristics of the floods to their geomorphic consequences.
F. Comiti, L. Marchi, P. Macconi, M. Arattano, G. Bertoldi, M. Borga, F. Brardinoni, M. Cavalli, V. D'Agostino, D. Penna, J. Theule, 2014, A new monitoring station for debris flows in the European Alps_ first observations in the Gadria basin,
Natural hazards (Dordr., Online) 73 (2014): 1175–1198. doi_10.1007/s11069-014-1088-5,
DOI: 10.1007%2Fs11069-014-1088-5
Abstract
Debris-flow monitoring in instrumented areas is an invaluable way to gather
field data that may ...
Debris-flow monitoring in instrumented areas is an invaluable way to gather
field data that may improve the understanding of these hazardous phenomena. A new
experimental site has been equipped in the Autonomous Province of Bozen-Bolzano
(Eastern Alps, Italy) for both monitoring purposes and testing early warning systems. The
study site (Gadria basin) is a 6.3 km2 catchment subjected to frequent debris flows. The
monitoring system in the Gadria basin consists of rain gauges, radar sensors, geophones,
video cameras, piezometers and soil moisture probes. Transmission of data and alerts from
the instruments exploits in part radio technology. The paper presents the data gathered
during the first three years of activity, with two debris-flow events recorded at the station
varying in magnitude and characteristics, and discusses the perspectives of debris-flow
monitoring and related research.
Borga M.; Stoffel M.; Marchi L.; Marra F.; Jakob M., 2014, Hydrogeomorphic response to extreme rainfall in headwater systems_ Flash floods and debris flows,
Journal of hydrology (Amst.) 518 (2014): 194–205. doi_10.1016/j.jhydrol.2014.05.022,
DOI: 10.1016%2Fj.jhydrol.2014.05.022
Abstract
Flash floods and debris flows develop at space and time scales that conventional observation systems ...
Flash floods and debris flows develop at space and time scales that conventional observation systems for rainfall, streamflow and sediment discharge are not able to monitor. Consequently, the atmospheric, hydrological and geomorphic controls on these hydrogeomorphic processes are poorly understood, leading to highly uncertain warning and risk management. On the other hand, remote sensing of precipitation and numerical weather predictions have become the basis of several flood forecasting systems, enabling increasingly accurate detection of hazardous events. The objective of this paper is to provide a review on current European and international research on early warning systems for flash floods and debris flows. We expand upon these themes by identifying_ (a) the state of the art; (b) knowledge gaps; and (c) suggested research directions to advance warning capabilities for extreme hydrogeomorphic processes. We also suggest three areas in which advancements in science will have immediate and important practical consequence, namely development of rainfall estimation and nowcasting schemes suited to the specific space-time scales, consolidating physical, engineering and social datasets of flash floods and debris-flows, integration of methods for multiple hydrogeomorphic hazard warning.
V.J Cortes Arevalo; T. Sprague3; S. Frigerio; T. Bogaard; S. Sterlacchini, 2014, The role of community knowledge and participation for hydraulic-structure inspections_ Combining knowledge with action through citizen-science projects,
International Conference on Analysis and Management of Changing Risks for Natural Hazards, Padua, Italy, 18-19 November 2014,
Abstract
This paper analyses opportunities and challenges of volunteers' hydraulic-structure
inspections to enhance organizational capacity. There is ...
This paper analyses opportunities and challenges of volunteers' hydraulic-structure
inspections to enhance organizational capacity. There is an increasing interest of risk
managers such as municipal offices, civil protection, water authorities and geological surveys
on using community knowledge to support adaptive management strategies for hydrometeorological
hazards. One way in which this knowledge can be utilized is through the
implementation of citizen-science projects. Thereby, scientists and risk managers enlist and
train citizens-volunteers to better understand hazard related processes e.g. changes on the
functional status of check dams (Cortes et al., 2014). Citizen-science projects could support
the increasing frequency, timeliness and coverage of surveillance activities (Flanaging and
Metzger, 2008). That is especially important under dynamic environmental conditions or
remote settings i.e. mountain basins (de Jong, 2013). Research methods followed the
framework presented in Figure 1 to identify opportunities and challenges of combining
volunteers' knowledge into actions through citizen-science projects. Thereby, a pilot citizenscience
project on volunteers' hydraulic-structure inspections was designed in the Fella basin.
That is a mountain basin in the North-eastern Italian Alps of the Friuli Venezia Giulia region.
Project design started from exploratory interviews with stakeholders. Then, continues with the
analysis of feedback provided by participants during pilot data-collection exercises. Overall,
risk managers are willing to consider volunteers' inspections only to pre-screen potential
problems that may require preventive maintenance. Findings highlight the importance of a
culture of volunteer activities and the role of institutional frameworks in supporting volunteers'
involvement. Results also account for the role of ICT tools and information management
systems to collect, manage and evaluate volunteers' reports. However, challenges to make
from this pilot a perennial activity stem up on the importance of volunteers' training as well as
coordination and communication strategies between actors involved. Therefore, inspection
guidelines should support completeness and precision of volunteers' reports. Training
strategies should also account for providing feedback to participants about the data-quality
collected after every inspection campaign. Moreover, sustainable implementations of citizenscience
projects require efforts to enhance coordination and communication with volunteers.
Such requirement should also apply between the different risk managers that may benefit from
volunteers' data. In consequence, opportunities to enhance organizational capacity through
citizen science projects require a flexible design framework accounting for available actors and
resources in the local context. Strengthen communication and coordination between those
actors is a vital element towards sustainable implementations on long-term basis.
Brardinoni F., Scotti R., Cavalli M., Mair V., 2014, Landslide and debris-flow sediment flux in glacial and periglacial mountain drainage basins of the Eastern Italian Alps,
GSA Annual Meeting, Vancouver, BC (Canada), 19-22 October 2014,
Abstract
While it is widely recognized that deglaciation and permafrost degradation can induce generalized instability in ...
While it is widely recognized that deglaciation and permafrost degradation can induce generalized instability in steep mountain terrain, beyond the documentation of single catastrophic mass-wasting events, there appears to be little empirical work on how the colluvial sediment cascade functions under conditions of increasing atmospheric temperature rise in a formerly glaciated landscape structure. Understanding and quantifying the influence of similar transient conditions on mass-wasting processes holds critical long-term implications on the overall sediment flux reshaping post-LGM landscape evolution, as well as more practical short-term applications on water quality issues, damage control to infrastructure, and reservoir siltation.
We present an integrated approach that aims to_ (i) document the spatial distribution of mass-wasting activity and sediment production in the Saldur River basin (97 km2); (ii) detect causal linkages between mass-wasting intensity, the potential spatial distribution of discontinuous permafrost, and patterns of glacier retreat; (iii) identify source-to-sink colluvial sedimentary pathways as modulated by the spatial organization of active and relict glacial and periglacial landforms; and (iv) test the reliability of a geomorphometry-based index of sediment connectivity.
To these ends, we map rock glaciers, protalus ramparts and moraines, and compile a field- and air photo-based multi-temporal (1959-1969-1982-1997-2000-2006-2008-2011) inventory of colluvial sediment sources. We then combine these data with two historical datasets of debris flow and landslide events (both implemented and maintained by the Autonomous Province of Bolzano) and analyse mass-wasting spatial distribution and intensity in relation to proximity to glacier fronts, intact and relict periglacial landforms, and a permafrost index map (i.e., PermaNET; http_//www.permanet-alpinespace.eu/).
This work is part of SedAlp (www.sedalp.eu), a project funded through the Alpine Space Programme, and benefits from COST Action ES1306_ Connecteur.
Comiti F., Bertoldi W., Cavalli M., Theule J., Trevisani S., 2014, Channel morphology through airborne LIDAR data_ recent advances from mountain streams to large rivers.,
34th EARSeL Symposium_ European remote sensing - new opportunities for science and practice, Warsaw (Poland), 16-20 June 2014,
Abstract
Airborne Laser Scanner (ALS) surveys are widely used to obtain high-resolution DTMs to be used ...
Airborne Laser Scanner (ALS) surveys are widely used to obtain high-resolution DTMs to be used in
natural hazards preventive analysis, e.g. flood and debris-flow modelling, as well as to reconstruct
sediment budget through DoD (DEM of Difference) analysis, in particular in mountain basins after large
events . In contrast, the use of ALS to capture the morphometric features of stream channels is less
favorable as the infrared signal, characteristic of the most common LiDAR instruments, do not
penetrate deep water bodies and thus do no permit to analyze the wet portion of channels. Yet, surveys
carried out by these instruments can provide sufficient data to characterize and analyze
morphometrically stream channels featuring either very shallow flows relative to bed roughness(e.g.
steep mountain channels) or relatively limited wet areas (e.g. braided rivers). So far, very few
investigations have deployed bathymetric LiDAR surveys, also known as green LiDAR, to map river
systems. Bathymetric LiDAR has the potential to offer high-resolution DTMs for morphometric analysis
in river systems complementary to those mentioned above (i.e. channels with perennial and substantial
wet areas) and where bathymetric surveys using boats are not easily carried out due to fast and
turbulent flows. These conditions are typical of mild-sloping, single-thread or wandering mountain
rivers, widely distributed worldwide, in which detailed morphometric analysis are thus very challenging
when carried out through traditional approaches. We will present a state of the art of morphometric
analyses used to characterize channel morphology, including published and unpublished examples
from step-pool channels as well as from sinuous-meandering and braided rivers, based on both infrared
and green LiDAR data.
Lucia A., Antonello A., Campana D., Cavalli M., Crema S., Franceschi S., Marchese E., Niedrist M., Schneiderbauer S., Comiti F., 2014, A simplified GIS-based model for large wood recruitment and connectivity in mountain basins.,
EGU General Assembly 2014, Vienna (Austria), 27 April - 2 May 2014,
M. Cavalli, B. Goldin, S. Crema, L. Marchi, 2014, Application and testing of a GIS-based sediment connectivity model in the Venosta valley (Eastern Italian Alps),
EGU General Assembly 2014, Vienna (Austria), 27 April - 2 May 2014,
Brardinoni F., Sosio R., Scotti R., Cavalli M., Comiti F., Mair V., 2014, Linking permafrost distribution, glacial retreat and colluvial sediment dynamics in the Saldur River basin, Eastern Italian Alps,
EGU General Assembly 2014, Vienna (Austria), 27 April - 2 May 2014,
Abstract
In the last three decades generalized atmospheric temperature rise has produced rapid glacial retreat and ...
In the last three decades generalized atmospheric temperature rise has produced rapid glacial retreat and permafrost
degradation in high mountain environments of the European Alps. While it is widely recognized that these changes
can impart general instability to mountain slopes (i.e. several projects have documented single case studies of
high magnitude-low frequency, catastrophic slope failures), to our knowledge, there appears to be little empirical
data available for investigating the spatial distribution of mass-wasting intensity through time in high mountain
areas in relation to permafrost degradation and deglaciation patterns. This is a critical shortcoming. Understanding
and quantifying the influence of similar transient conditions on mass-wasting processes holds critical long-term
implications on the overall sediment flux reshaping mountain landscapes (e.g., post-LGM landscape evolution), as
well as more practical short-term applications on water quality issues, damage control/prevention to infrastructure,
and reservoir siltation, to mention some.
In this contribution we present an integrated approach that aims to_ (i) document the spatial distribution of
mass-wasting activity and sediment production in the Saldur River basin (97 km^2); (ii) detect causal linkages
between mass-wasting intensity, the potential spatial distribution of discontinuous permafrost, and patterns of
glacier retreat; and (iii) identify source-to-sink colluvial sedimentary pathways as modulated by the spatial
organization of glacial and periglacial landforms.
To these ends, we map rock glaciers, protalus ramparts and moraines, and compile a field- and air photo-based
multi-temporal (1959-2012) inventory of colluvial sediment sources. We then combine these data with two
historical datasets of debris flow and landslide events (both implemented and maintained by the Autonomous
Province of Bolzano) and analyse mass-wasting spatial distribution and intensity in relation to proximity of glacier
fronts, intact and relict periglacial landforms, and a permafrost index map (implemented through PermaNET;
http_//www.permanet-alpinespace.eu/).
This work is part of SedAlp (www.sedalp.eu), a project funded through the Alpine Space Programme.
Cavalli M., Crema S., Marchi L., 2014, Guidelines on the Sediment Connectivity ArcGis Toolbox and stand-alone application,
2014,
Abstract
Sediment connectivity, i.e. the degree of linkage that controls sediment fluxes throughout landscape, and, in ...
Sediment connectivity, i.e. the degree of linkage that controls sediment fluxes throughout landscape, and, in particular, between sediment sources and downstream areas, is a key issue in the study of sediment transfer processes in mountainous catchments. The spatial characterization of connectivity patterns in the catchment allows estimation of the contribution of a given part of the catchment as sediment source, and defines sediment transfer paths. A reliable assessment of sediment connectivity is especially useful for giving management priorities. The assessment of sediment connectivity is of particular importance in alpine headwaters, in which both complex and rugged morphology, and heterogeneity in type, extent and location of sediment sources cause large variability in the effectiveness of sediment transport processes. The control of morphology on spatial sediment connectivity acts through sediment transfer on hillslopes and unchanneled valleys, hillslope-channel coupling and decoupling, and sediment transfer along the channel network. In this document, background theory, installation steps and user guidelines of two utilities for the derivation of the Index of Connectivity (IC), as expressed in Cavalli et al. (2013), developed in the frame of the SedAlp project are presented. The utilities are_ (i) a Toolbox for ArcGis 10.1 and 10.2 and, (ii) a standalone application not requiring the use of any GIS software. The need for the development of such tools comes from the increasing interest in sediment connectivity issues (Fryirs 2013; Baartman et al. 2013) and its semi-quantitative assessment (Heckmann and Schwanghart 2013; Cavalli et al. 2013; Meßenzehl et al., 2014) to estimate the effectiveness of sediment transport processes at catchment scale. Moreover, the possibility to relate a quantitative estimate of sediment connectivity to sediment sources databases can improve hazard and risk assessment in order to mitigate the effects of dangerous phenomena like debris flows. With an integrated approach, which encompasses sediment sources mapping and connectivity assessment, it is indeed possible not only to evaluate the general availability of sediment but also to estimate the potential for this sediment to reach specific targets.
Blasone G., Cavalli M., Marchi L., Cazorzi F., 2014, Monitoring sediment source areas in a debris-flow catchment using terrestrial laser scanning,
Catena (Cremling.) 123 (2014): 23–36. doi_10.1016/j.catena.2014.07.001,
DOI: 10.1016%2Fj.catena.2014.07.001
Abstract
Geomorphic changes caused by three debris-flow events in a small mountain catchment (Moscardo Torrent, Eastern ...
Geomorphic changes caused by three debris-flow events in a small mountain catchment (Moscardo Torrent, Eastern Italian Alps) were investigated by means of multitemporal terrestrial laser scanning (TLS) surveys over three areas exposed to debris-flow dynamics. For these areas, DEM of Differences (DoDs) with a 0.2 m spatial resolution allowed the assessment of elevation uncertainty as spatially variable by applying the fuzzy inference system (FIS) proposed by Wheaton et al. (2010). Along with two commonly used parameters affecting Digital Elevation Model (DEM) accuracy, such as terrain slope and point density, we developed and employed in the FIS a new index, named Vegetation Noise, that takes into account the disturbance caused by the vegetation cover on the DEM accuracy. The results of volumetric budgets of the surveyed sediment source areas derived from the DoD analysis were compared with debris-flow volumes estimated from flow stage measurements at the instrumented channel reach. On the one hand, the discrepancies arising from this comparison underline the limitations of TLS surveys over morphologically complex areas such as debris-flow catchments. On the other hand, the TLS unveils the geomorphic changes at the scale of the single event, because a terrestrial survey is usually easier to carry out than an aerial one. The analysis of DEM quality and uncertainty indexes correlation may help to refine methods for spatializing elevation errors and improving the reliability of the models.
Bersan S., Schenato L., Rajendran A., Palmieri L., Cola S., Pasuto A., Galtarossa A., Simonini P., 2014, In soil distributed temperature measurements for small scale physical models,
XX Riunione Nazionale di Elettromagnetismo, pp. 529–532, Padova, 15-18/09/2014,
Abstract
A distributed temperature optical fibre sensors system with a sub-centimetre spatial resolution has been incorporated ...
A distributed temperature optical fibre sensors system with a sub-centimetre spatial resolution has been incorporated in a sand-box model. The aim is to monitor the temperature field induced in the sand by a horizontal water flow with inflowing water maintained at a constant temperature higher than the room temperature. It is shown that by distributed fibre optic sensors accurate temperature mapping in a soil sample can be obtained. The measurements has such a richness of detail which is not comparable with that achievable with any other system of point-wise sensors.
Schenato L., 2014, Fiber-Optic Sensors for Geo-Hydrological Applications_ basic concepts and applications,
Rendiconti online Società Geologica Italiana 30 (2014): 51–54. doi_10.3301/ROL.2014.11,
DOI: 10.3301%2FROL.2014.11
Abstract
In this short note, basic concepts about fiber-optic sensors are presented, with respect to applications ...
In this short note, basic concepts about fiber-optic sensors are presented, with respect to applications in geology and hydrology. Fiber-Bragg gratings and distributed fiber-optic sensors are then
discussed more in detail.
Mantovani M., Scherneck H.-G, 2013, DInSAR investigation in the Parvie end-glacial fault region, Lapland, Sweden.,
International journal of remote sensing (Online) 34 (2013): 8491–8502.,
Abstract
Northern Fennoscandia bears witness to the Pleistocene glaciation in the form of a series of ...
Northern Fennoscandia bears witness to the Pleistocene glaciation in the form of a series of large faults that have been shown to have ruptured immediately after the retreat of the ice sheet, about 9500 years ago. The largest one, known as the Pärvie fault, consists of a 155 km long linear series of fault scarps forming north-northeast-trending, that stretch west of Kiruna, Lapland. End-glacial intra-plate faults of this extent are very rare in the continental crust and the Pärvie system represents one of the major fault zone structures of this type in the world. Seismological evidence shows that there is still noticeable seismic activity, roughly one event of magnitude 2 per year that can be attributed to the fault. Nevertheless assessing its state of activity is a difficult task due to the extent and remoteness of the area. This study is aimed at the determination of crustal motion around the Pärvie fault zone using the differential inter-ferometric synthetic aperture radar (DInSAR) technique, based on images acquired with the European
Space Agency (ESA) satellites European Remote Sensing (ERS) 1, ERS-2, and the Environmental Satellite (ENVISAT). We present results achieved in terms of deformation of the crystalline bedrock along different sectors of the fault where high levels of coherence were obtained, even from image pairs several years apart. This finding does not exclude deformation in other segments, as observing conditions are not always as favourable in terms of data availability.
Rainato R.; Picco L. L.; Cavalli M.; Mao L. L.; Delai F.; Ravazzolo D.; Lenzi M.A., 2013, Evaluation of short-term geomorphic changes along the Tagliamento river using LiDAR and terrestrial laser scanner surveys,
Journal of agricultural engineering (Pisa) 44 (2013): 80–84. doi_10.4081/jae.2013.(s1):e15,
DOI: 10.4081%2Fjae.2013.(s1):e15
Abstract
In the recent years a change in the predominant morphology of several river environments has ...
In the recent years a change in the predominant morphology of several river environments has taken place, consisting in a reduction of the braided pattern in favor to wandering or straight configurations. This evolution seems to be due, according to the scientific community, to anthropic causes and, in particular, to the alteration of flow regimes as well as the reduction of sediment transport. Braided rivers are characterized by two or more active channels, separated by bars and fluvial islands and normally feature a high morphological dynamism. This dynamism is the result of the interaction among different elements as sediment supply, flow regime and in-channel and perifluvial vegetation. These factors have a fundamental role in the erosion and deposition processes which are the basis of the morphological changes. The aims of this study are the assessment of the short period geomorphic and volumetric changes occurred along a reach of the Tagliamento River and the comparison between the results obtained from LiDAR (Light Detection and Ranging) and TLS (Terrestrial Laser Scanner) data. The Tagliamento river is a natural gravel-bed river located in the NE of Italy, characterized by a relatively low degree of human disturbances. The analyses were carried out considering two different scales (a reach of about 430 ha and a sub-reach of about 25 ha) and were based on two subsequent datasets in order to investigate the shortterm geomorphic changes due to eight significant floods. The surveys were performed using two different datasets derived from LiDAR and TLS technologies and used to analyze the reach and sub-reach respectively. The short-term estimates of geomorphic and volumetric changes were performed using DEMs of Difference (DoD) based on a Fuzzy Inference System. The results have confirmed the high dynamism of the Tagliamento river, estimating a prevalent deposition at reach and a predominant erosion at sub-reach levels. Finally, a comparative qualitative assessment of the output derived from the different data sources was performed, showing little differences between the two survey methods that proved to be both precise and reliable.
Palmieri L., Schenato L., Galtarossa A., 2013, The Role of Anisotropy in Few-Mode Optical Fibers,
2013 Optical Fiber Communication Conference and Exposition and the National Fiber Optic Engineers Conference, OFC/NFOEC 2013, Anaheim, CA; United States, 17-21/03/2013,
Abstract
We analyze beating and coupling within LP(1,1) manifold, caused by fiber anisotropy. Results suggest that ...
We analyze beating and coupling within LP(1,1) manifold, caused by fiber anisotropy. Results suggest that spinning the fiber may reduce modal dispersion as for nondegenerate LP(0,1) modes of nonideal fibers.
Palmieri L., Schenato L., 2013, Distributed Optical Fiber Sensing Based on Rayleigh Scattering,
The Open optics journal 7 (2013): 104–127. doi_10.2174/1874328501307010104,
DOI: 10.2174%2F1874328501307010104
Abstract
Optical fiber sensors offer unprecedented features, the most unique of which is the ability of ...
Optical fiber sensors offer unprecedented features, the most unique of which is the ability of monitoring variations of the observed physical field with spatial continuity along the fiber. These distributed optical fiber sensors are based on the scattering processes that originate from the interaction between light and matter. Among the three different scattering processes that may take place in a fiber--namely Rayleigh, Raman and Brillouin scattering, this paper focuses on Rayleigh-based distributed optical fiber sensors. For a given optical frequency, Rayleigh-based sensors exploit the three main properties of light_ intensity, phase and polarization. All these sensing mechanisms are reviewed, along with basic principles, main acquisition techniques and fields of application. Emphasis, however, will be put on polarization-based distributed optical fiber sensors. While they currently represent a niche, they offer promising unique features worth being considered in greater detail.
RINALDO GENEVOIS, PIA ROSELLA TECCA, 2013, The Vajont landslide_ state-of-the-art.,
Proceedings of the International Conference on Vajont 1963-2013. Thoughts and analyses after 50 years since the catastrophic landslide, Padua, Italy, October 8-10, 2013, pp. 15–39, Padova, Italia, 8-10/10/2013,
Marco Cavalli, Lorenzo Marchi, Massimo Arattano, 2013, Protocol for Debris-flow Monitoring,
pp.1–35, 2013,
Abstract
Monitoring of debris flows in instrumented catchments permits collection of
data on these phenomena and provides ...
Monitoring of debris flows in instrumented catchments permits collection of
data on these phenomena and provides a valuable link with
geomorphological and topographical observations of erosion, sediment
supply and channel evolution. The recorded data can serve as a basis for
implementing of early warning systems that provide defense against
debris-flow risk. The quantification of sediment volumes transported by
debris flows along with their temporal frequency, timing, flow
characteristics (i.e. velocity, flow depth, peak discharge, density) are of
crucial importance for hazard assessment, land-use planning and design of
torrent control structures. In addition, instrumented basins provide highquality
information for deriving regional thresholds of rainfall intensity
and/or cumulated values for debris-flow triggering to be used in warning
systems.
Japan and China have pioneered debris-flow monitoring (Okuda et al.,
1980; Zhang, 1993) and sites instrumented in these countries still play a
significant role in debris-flow research, also thanks to the long time series
of recorded data (Hu et al., 2011a, b; Suwa et al., 2011). In Taiwan, the
frequent occurrence of high-magnitude debris flows with severe damage to
settlements has urged the installation of equipment for monitoring debris
flows and for issuing warnings in a number of sites (Yin et al., 2011).
Amongst early experiences on instrumental observations of debris flows in
the United States, are the monitoring campaigns by Pierson (1986) in
channels on the flanks of Mount St. Helens. More recently, the installation
of monitoring equipment at Chalk Cliffs, a small, very active catchment in
the Colorado Rocky Mountains, has started providing valuable information
and data on debris-flow triggering and flow dynamics (Coe et al., 2008;
McCoy et al., 2011). In Europe, the first catchment instrumented for debris
-flow monitoring was probably the Moscardo Torrent in the Eastern Italian
Alps (Arattano et al., 1997; Marchi et al., 2002). Other sites were
3
instrumented in the late 1990s and early 2000s in Italy (Tecca et al., 2003)
and Switzerland (Hürlimann et al., 2003). Amongst these monitoring sites,
the Illgraben catchment (Switzerland) deserves to be mentioned because
of innovative measurements on forces and pore fluid pressure in debris
flows (Mc Ardell et al., 2007) and channel-bed erosion (Berger et al.,
2011). Recent development of monitoring activities in Europe, which
include installations in Austria (Kogelnig et al., 2011), France (Navratil et
al., 2012; 2013b), and Spain (Hürlimann et al., 2011) indicates the high
interest for this sector of debris-flow studies.
The number of monitoring sites and the amount of recorded data on debris
flows remains still limited if compared to landslides and fluvial sediment
transport. Moreover, the large variability of debris-flow features, their
dependence on local topographical, geological and climate conditions
makes the collection of more data in instrumented catchments of the
utmost importance.
This protocol aims at describing minimum requirements for a debris-flow
monitoring site and illustrating the existing sensors and methods of
measurements and data collection. In the SedAlp Project several
catchments are instrumented for debris-flows monitoring_ Rio Gadria by
the Autonomous Province of Bozen-Bolzano (PP1) with the collaboration of
CNR-IRPI (PP4), Rio Chiesa by ARPAV (PP2), Moscardo Torrent by CNR-IRPI
(PP4), Manival and Réal torrents by Irstea (PP7). Monitoring concepts of
these pilot areas were used to draft the protocol; devices and
measurements methods implemented in European debris-flow monitoring
sites outside the project were also considered in order to provide a
comprehensive view of existing methods for debris-flow monitoring.
Pasuto A., Oi H., 2013, Valutazione della pericolosità e gestione del rischio idrogeologico_ esperienze in Italia e Giappone,
ESONDA 2013, Ferrara, 19 September, 2013,
Stefani M.; Mantovani M.; Mair V.; Marcato G.; Pasuto A.; Nossing L., 2013, The Ganderberg landslide (South Tyrol, Italy): Mitigation of residual risk by real-time monitoring,
Early warning, Instrumentation and Monitoring, pp. 531–535, 2013,
Abstract
The whole flank of Ganderberg western slope (3.75 km2) (lat. 46°51'12'', long. 11°10'15'') is involved ...
The whole flank of Ganderberg western slope (3.75 km2) (lat. 46°51'12'', long. 11°10'15'') is involved in a Deep Seated Gravitational Slope Deformation phenomenon. The upper part is characterized by several joint surfaces, with possible wedge failure mechanisms. In particular, the northern crown ridge is divided into three sectors with noticeably different indications of subsidence and displacement. The orientation of the joint planes and evidence of vertical movements of a distinct rock block allow a potential rock avalanche to be hypothesized (up to the volume of 4.5 x 105 m3). On the basis of historical archives analysis it was found that the same slope was involved in a rock avalanche event dating back to 1401. The landslide deposits created a 35 m deep lake, damming the Passer Torrent, creating the Passeirer Wildsee or Kummersee. Aim of the study is the evaluation of residual risk scenarios and its mitigation by means of monitoring and data interpretation using Saito and Fukuzono techniques.
Cortes V.J., Frigerio S., Schenato L., Pasuto A. & Sterlacchini S., 2013, Review of the current risk management strategies in Europe for hydro-meteorological hazards at protection and emergency level,
FLOODrisk 2012 - the 2nd European Conderence on FLOODrisk Management, pp. 971–980, Rotterdam, The Netherlands, 20-22 November 2012,
Abstract
A review of the current emergency response strategies at European level was carried out
from the ...
A review of the current emergency response strategies at European level was carried out
from the key conclusions and recommendations identified within past experiences of developed platform
for civil protection and emergency management. The review is focused on the recent research initiatives
funded by the European Community about methods and techniques for emergency response in case of
flooding and debris flow risks, mainly. The ultimate aim is to reduce the fragmentation of the research on
hydro-meteorological hazards so to possibly identify a best practice on disaster risk management. This
paper is organized as follows, first a brief overview on emergency response strategies is presented along
with an analysis of the challenges that arisen while implementing the following tools_ geo-information
and remote sensing, emergency plans, early warning and decision support systems. Then, conclusions
have been drawn.
Pasuto, Alessandro; Soldati, Mauro, 2013, Lateral Spreading,
Treatise on Geomorphology, pp. 239–248. San Diego, California_ Academic Press, 2013,
Abstract
The main conceptual and terminological issues related to lateral spreading as an extension of a ...
The main conceptual and terminological issues related to lateral spreading as an extension of a cohesive and fractured rock or soil mass over a softer underlying material are presented and accompanied by a brief outline of the state-of-the-art on the topic. Then the geomorphic features related to the two main types of spreading (rock spreading and soil spreading) are illustrated, with reference to the geological conditions in which they take place, as well as to their causes and evolution. Finally, some considerations on the hazard and planning implications are provided. © 2013 Elsevier Inc. All rights reserved.
Devoto S., Biolchi S., Bruschi V.M., Gonzalez-Diez M., Mantovani M., Pasuto A., Piacentini D., Schembri J.A., Soldati M., 2013, Landslides along the north-west coast of the Island of Malta,
Landslide Inventory and Susceptibility and Hazard Zoning, pp. 57–64, 2013,
Abstract
The paper shows the results of geomorphological and engineering-geological investigations carried out along the north-western ...
The paper shows the results of geomorphological and engineering-geological investigations carried out along the north-western coast of the Island of Malta, with special emphasis on landslides. Field surveys and aerial-photo interpretation allowed the recognition, identification and mapping of a series of landslides of different type and size,
some of which showing evidence of activity. Coastal instability in the studied area is deeply controlled by structural factors, such as tectonic and stratigraphic ones. The
research envisaged a multidisciplinary approach, which also included landslide monitoring in specific sites which were selected for detailed investigations, owing to the peculiarity of the instability processes occurring and for the related hazard and risk conditions. The paper outlines the research phases and the results achieved which proved to be fruitful thanks to the application of different methodologies for the study of coastal landslides. Particular attention has been paid to rock spreading phenomena, which are widespread along the northwestern coast of Malta due to the superimposition of limestones over clayey terrains.
Schenato L., Palmieri L., Autizi E., Gruca G., Iannuzzi D., Pasuto A., Galtarossa A., 2013, Interrogation of multiple ferrule-top-cantilever sensors for acoustic emission sensing,
Fifth European Workshop on Optical Fibre Sensors, Cracovia, 19-22 May 2013,
Abstract
A simple, yet effective, setup for the simultaneous interrogation of multiple ferrule-top-cantilever sensors for acoustic ...
A simple, yet effective, setup for the simultaneous interrogation of multiple ferrule-top-cantilever sensors for acoustic sensing is here presented and experimentally tested with two ferrule-top-cantilever sensors; results confirm the feasibility of the approach.
Devoto S., Forte E., Mantovani M., Mocnik A., Pasuto A., Piacentini D. , Soldati M., 2013, Integrated monitoring of lateral spreading phenomena along the north-west coast of the Island of Malta.,
Early warning, Instrumentation and Monitoring, 2013,
Abstract
Landslides, and especially lateral spreading, are responsible for the main landforms observable along the northwestern ...
Landslides, and especially lateral spreading, are responsible for the main landforms observable along the northwestern coast of the Island of Malta. A series of rock spreading
phenomena, and associated mass movements, have been recognised in this area and the most significant cases have been investigated by means of a multi-technical approach which envisaged geomorphological survey and mapping, geophysical analyses and monitoring of displacements. The aim of the study was to define whether rock spreading phenomena are active along the investigated coastal stretch and, possibly, to determine the rate of movement of the most relevant cases. In this framework, a multidisciplinary approach was used and different techniques were tested and applied on a specific site, which was selected for the presence of an extensive rock spread phenomenon which may induce hazard conditions. The site is located at Il-Prajjet (Anchor Bay), a narrow inlet where a tourist attraction is located. Research activities have been carried out at Il-Prajjet since 2006 when a GPS network of eight benchmarks was installed. This technique was chosen because it proved to be a powerful tool in the study of similar ground deformation in coastal and mountain areas, showing high accuracy and reliability. Once GPS monitoring had showed that rock spreading was active, further techniques were applied in order to achieve an in-depth knowledge of the instability processes occurring at Il-Prajjet. The paper illustrates the results so far achieved thanks to GPS monitoring, tape extensometer measurements, SAR interferometric analyses and GPR investigations.
Bossi, G., Frigerio S., Mantovani, M., Schenato L., Pasuto, A., Marcato, G., 2013, Hazard assessment of a potential rock avalanche in South Tyrol, Italy_ 3D modeling and risk scenarios,
Italian journal of engineering geology and environment (Testo stamp.) 2 (2013): 221–227. doi_10.4408/IJEGE.2013-06.B-19,
DOI: 10.4408%2FIJEGE.2013-06.B-19
Abstract
A large DSGDS (Deep-Seated Gravitational Slope Deformation) which extends on an area of 3.75 km2 ...
A large DSGDS (Deep-Seated Gravitational Slope Deformation) which extends on an area of 3.75 km2 affects the southwest flank of Mount Ganderberg some 40 km north of Bolzano. The gravitational sagging of the slope is generating a wide field of tension cracks in the crown area where a rock slab of about 800.000 m3 shows clear precursory signs of possible detachment. In 1401 a rock avalanche detaching from the same area dammed the Passer River thus creating a 35 m deep lake which through sequential breaching caused many casualties in the villages downstream. Using geomorphological survey and historical analysis it was possible to estimate the volume of the landslide deposit in 2 × 106 m3. In this study the historical event is back-analyzed using the 2D code DAN-W in order to select the proper soil parameters to use in the modelling of the present potential rock avalanche. Then a 3D modelling is carried out using DAN3D software to evaluate the run-out scenario and the shape of the natural dam. Owing to the relevant discharge of the Passer River, a 2 × 106 m3 lake might be quickly filled. This can cause the breaching and subsequent collapse of the landslide dam with great risk and potentially heavy damages for the downstream population.
Cortes V.J., Charrière M., Aye Z., Bossi G., Viero A., Frigerio S., Schenato L., Sterlacchini S., Bogaard T. & Pasuto A., 2013, First level inspection by trained-volunteers of torrent control structures in mountainous catchments_ towards a quality-evaluation of data collected,
EGU - European Geosciences Union, Vienna, Austria, 07-12 April 2013,
Abstract
Modern approaches for emergency management promote exchange of information between local authorities and
community aiming at ...
Modern approaches for emergency management promote exchange of information between local authorities and
community aiming at more appropriate and effective ways to manage hydro-meteorological risks1. In this framework,
risk communication should not only start during the build-up of the hazard, but also in pre-warning and
'peace' time and it contribute to better emergency preparedness. Lately, a rapid growth of interest emerges to enable
citizens to inspect hazard-related processes on their territory2. From the risk managers perspective, substantial
advantages of taking this citizen-based approach include (1) the opportunity to identify on a quick and 'relatively'
low cost basis one or more risk components at different geographical locations and (2) the ability to provide a
practical application for citizens interested in creating and communicating useful information toward establishing
a better understanding of their territory. From the citizens perspectives, it provides the opportunity to generate
benefit through increasing and encouraging interest for self-awareness as well as self-preparedness. However, the
use of citizen-based information also bring forth the need to train and establish standardized forms, guidelines and
tools, particularly if the data collected seek to be useful information for decision-making activities and emergency
management3.
In this research work, we address the question on the quality of data collected by volunteers for decision-making
activities. This in the framework of the civil protection organization of the Friuli-Venezia-Giulia (CP-FVG) and the
Italian study area of the CHANGES project, Municipality of Pontebba4. An experiment is carried out by analyzing
the results of a questionnaire form dealing with the inspection of the functional status of check dams and bridges
across streams. This form is filled by volunteers (in this case, citizens and university students), that register to a
web-portal with access by browser after a standardized training given by practitioners and scientists. During the
latter, the guidelines to fill the questionnaire, i.e. various conditions of hydraulic structures and the proposed criteria
for quality evaluation5, will be disseminated to the volunteers. The quality of the data are analyzed on the basis of
these guidelines in order to determine if the citizens-based data collection approach can be used to prioritize the
structures to be inspected by the risk managers.
Mantovani M., Devoto S., Forte E., Mocnik A., Pasuto A., Piacentini D., Soldati M., 2013, A multidisciplinary approach for lateral spreading investigation in the north-western coast of Malta.,
Landslides (Berl., Print) 10 (2013): 611–622.,
Abstract
Landslides are widespread along the north-western coast of the Island of Malta and are strictly ...
Landslides are widespread along the north-western coast of the Island of Malta and are strictly linked to the structural setting. Exemplary cases of rock spreading and block sliding phenomena characterise this stretch of coast. They are favoured by the overposition of two different geological units widely outcropping there, the Blue Clay Formation and the Upper Coralline Limestone Formation. The latter forms a wide plateau, bordered by vertical cliffs. At the foot of the cliffs, clayey terrains crop out and develop gentle slopes covered by large blocks detached and moved by rock spreading and block sliding phenomena. These mass movements are favoured by the fragile behaviour of limestones, which cap clays, otherwise characterised by visco-plastic properties. In order to investigate the kinematics and the evolution of these types of
coastal landslides, a multidisciplinary and multitechnical approach was applied on a study site, named Il-Prajjet, which provides a spectacular case of rock spreading evolving into block sliding. This paper illustrates the results achieved by means of different engineering geological and geophysical techniques allied with traditional detailed geomorphological survey and mapping. In particular, the surface displacements of the landslides were determined using long-term GPS observations, acquired approximately every 6 months, over a 4.5-year period. A network of GPS benchmarks were distributed on the edge of a limestone plateau affected by rock spreading and on a series of displaced blocks making up a large block slide, finally enabling the definition of the state of activity and the rates of movement to be performed. In addition, the results deriving from two continuous fissurimeters more recently installed at the edge of two persistent joints over the block sliding area are outlined, with reference to the correlation between variations of crack apertures and precipitation input. In order to identify main structural discontinuities and to reconstruct variability of underground surface contact between clays and overlying limestones, Resistivity Tomography profiles and GPR investigations were carried out. Finally, the results obtained by combining the outputs of geophysical surveys and different field monitoring activities can be considered a first step on which numerical models can be developed and validated, in order to assess landslide hazard and risk of this stretch of Maltese coastline.
Lorenzo Marchi, Giorgio Boni, Marco Cavalli, Francesco Comiti, Stefano Crema, Ana Lucía, Francesco Marra, and Davide Zoccatelli, 2013, The flash flood of October 2011 in the Magra River basin (Italy): rainstorm characterisation and flood response analysis,
EGU General Assembly 2013, Vienna (Austria), 07-12 April, 2013,
Abstract
On 25 October 2011, the Magra River, a stream of northwest Italy outflowing into the ...
On 25 October 2011, the Magra River, a stream of northwest Italy outflowing into the Ligurian Sea, was affected
by a flash flood, which caused severe economic damage and loss of lives. The catchment covers an area of 1717
km2
, of which 605 km2
are drained by the Vara River, the major tributary of the Magra River.
The flood was caused by an intense rainstorm which lasted approximately 20 hours. The most intense phase lasted
about 8 hours, with rainfall amounts up to around 500 mm. The largest rainfall depths (greater than 300 mm)
occurred in a narrow southwest - northeast oriented belt covering an area of approximately 400 km2
.
This flash flood was studied by analysing rainstorm characteristics, runoff response and geomorphic effects.
The rainfall fields used in the analysis are based on data from the Settepani weather radar antenna (located at
around 100 km from the study basin) and the local rain gauge network. Radar observations and raingauge data were
merged to obtain rainfall estimates at 30 min with a resolution of 1 km2
. River stage and discharge rating curves
are available for few cross-sections on the main channels. Post-flood documentation includes the reconstruction
of peak discharge by means of topographic surveys and application of the slope-conveyance method in 34 crosssections,
observations on the geomorphic effects of the event - both in the channel network and on the hillslopes
- and the assessment of the timing of the flood based on interviews to eyewitnesses. Regional authorities and
local administrations contributed to the documentation of the flood by providing hydrometeorological data, civil
protection volunteers accounts, photos and videos recorded during and immediately after the flood.
A spatially distributed rainfall-runoff model, fed with rainfall estimates obtained by the radar-derived observations,
was used to check the consistency of field-derived peak discharges and to derive the time evolution of the flood.
The assessment of unit peak discharges confirmed the severity of the flood, with values up to approximately 20
m^(3)/s/km^(-2) in catchments up to 10-20 km2. The strong spatial gradients of the precipitation had a major influence
on flood response, with large differences in peak discharge between neighbouring catchments. The magnitude of
sediment transport processes, featuring as well a large variability among sub-basins, seems to have been controlled
both by peak water discharge and by local geomorphological conditions affecting sediment supply, i.e. occurrence
of large landslides connected to the channel network. A striking characteristic of the flood event was the recruitment
and transport of large amounts of wood elements, deriving mostly from eroded portions of floodplains and islands
along the main channels.
Stefano Crema, Lorenzo Marchi, Francesco Marra, 2013, Hydrological control on the triggering of debris flows in alpine catchments_ storm analysis and basin response variability,
EGU General Assembly 2013, Vienna (Austria), 07-12 April, 2013,
Abstract
Three storm events, occurred in 2006, 2007 and 2009 in the upper Adige River basin ...
Three storm events, occurred in 2006, 2007 and 2009 in the upper Adige River basin (Eastern Alps, northern Italy)
have been analyzed. The first storm system (4 October 2006) generated a flash flood with almost no debris flows
and landslides, the second (21 June 2007) triggered a large number of debris flows and was characterized by a
relatively minor runoff response, and the third (4 September 2009) resulted in both a relevant flash flood response
and debris flows in minor streams. A strong interest both for civil protection and research purposes has been
devoted by local authorities and researchers to such events. The study methods include radar rainfall analysis,
hydrological modeling and GIS processing of spatial rainfall data and debris-flow locations. Precise information
on debris-flow location and related volumes were derived from a geo-spatial database of instability phenomena
implemented and managed by the Autonomous Province of Bolzano.
Patterns of rainfall distribution and relations between the main hydrological variables (cumulative rainfall,
intensity and antecedent moisture) have been analyzed to explain differences in catchments responses between
the three studied events. Radar rainfall data have permitted to analyze rainfall fields with high spatial resolution,
taking into account also the elevation variability of rainfall rates. The striking responses' contrast among the three
events is related to differences in antecedent moisture, space-time structure of the rainstorms, cumulative rainfall
and intensity distributions and temperature regime. The frequency analysis of the main hydrological variables
revealed to be a powerful tool capable of distinguishing, within a synoptic framework, the space-time-magnitude
variability of the events, so as to highlight the differences in flood and debris-flow response.
G. T. Aronica, M. Cavalli, E. Gaume, L. Marchi, S. Nasoa, Marco Borga, 2013, The Longano river extreme flood on the November 22 2011 (Sicily, Italy): post-event survey and analysis,
7th HyMeX Workshop (Hydrological cycle in the Mediterranean Experiment), Cassis (France), October 7-10, 2013,
Abstract
On 22 November 2011, an exceptional rainstorm hit the North-East part of Sicily (Italy) producing ...
On 22 November 2011, an exceptional rainstorm hit the North-East part of Sicily (Italy) producing local heavy rainfall, mud-debris flow and flash flooding. The storm was concentrated on the Tyrrhenian Sea coast near the city of Barcellona Pozzo di Gotto within the Longano catchment. The flood peak discharge of the Longano river in the city of Barcellona (about 230 m3/s for 26 km2) is close to the highest values reported in Europe for similar watershed areas.
Rainfall data from raingauge and meteorological radar were analysed and a detailed study of the hydrological response of the catchment was performed by means of rainfall-runoff modelling and flood frequency analysis. The results of the rainfall-runoff model were compared with peak discharges estimated from field observations (cross-sections survey, water marks, witnesses interviews and video recordings). Flood inundation and propagation in the city were modelled using an hydraulic model based on DSV equations calibrated using the data collected (water depths and flow velocities). A geomorphological survey was also conducted to ascertain the evolution of the phenomenon and related sediment processes analysis.
Eric Gaume, Lorenzo Marchi, 2013, Recent post-flash flood surveys conducted within the HyMeX project,
7th HyMeX Workshop (Hydrological cycle in the Mediterranean Experiment), Cassis (France), 7-10 October 2013,
Abstract
Spatial and temporal scales of occurrence of flash floods make these events particularly difficult to ...
Spatial and temporal scales of occurrence of flash floods make these events particularly difficult to observe by means of conventional measurement networks of rain and discharge. As a consequence, post-event surveys play an important role in the analysis of flash floods_ they permit assessing peak discharge in ungauged streams, reconstructing the time evolution of the floods and documenting their geomorphic effects.
The survey of flash floods in Hymex aims at extending databases implemented in previous projects (e.g. Hydrate, 6th Framework Programme, www.hydrate.tesaf.unipd.it) and improving the understanding of flash flood formation in the Mediterranean. It is expected, in particular, that continuing flash flood documentation will improve the spatial coverage in the Mediterranean area (events in eastern Mediterranean are underrepresented in existing flash flood catalogues).
Four floods have been documented from 2010 to 2012 by means of post-event field observations and analysis of hydrometeorological data_ Var Department (SE France), June 2010, Bacchiglione River basin (NE Italy), November 2010, Magra River basin (NW Italy), October 2011, Longano catchment (Sicily), November 2011. Flood magnitude in some catchment hit by these flash floods approaches maxima known in the Mediterranean region. The studied event, moreover, have permitted focusing on different features relevant for the assessment of flash flood response_
- influence of geological settings on flood response (Var Department);
- morphological changes of channel beds and recruitment and transport of large wood (Magra River basin);
- complex sediment dynamics and flood analysis in an urban context (Longano catchment).
The flood of November 2010 in the Bacchiglione River basin has been considered, although it does not show all distinctive attributes of flash floods, because it was most severe flood in the studied area since November 1966 and it is representative of increased flood risk due to land use changes occurred in the last decades (expansion of industrial and urban areas).
The contribution summarises the most relevant characteristics of the investigated events and outlines their significance in the context of the ongoing study of flash floods in Hymex.
Zoccatelli D., Marchi L., Borga M., 2013, Flash floods in Europe and in the Mediterranean region_ characterisation and risk mitigation strategies,
Giornate dell'Idrologia della Società Idrologica Italiana - 2013 "Idrologia, Difesa del Territorio e Gestione delle piene_ le tre anime della Direttiva Alluvioni", Venezia, 18-20/12/2013,
Lorenzo Marchi, Eric Gaume, 2013, Documentation and analysis of recent flash floods in Italy and in southern France,
Florisa Melone Memorial Conference, Assisi (Perugia), October 10-11, 2013,
Abstract
Spatial and temporal scales of occurrence of flash floods make these events particularly difficult to ...
Spatial and temporal scales of occurrence of flash floods make these events particularly difficult to observe by means of conventional measurement networks of rain and discharge. As a consequence, post-event surveys play an important role in the analysis of flash floods_ they permit assessing peak discharge in ungauged streams, reconstructing the time evolution of the floods and documenting their geomorphic effects.
Surveys of flash floods are currently carried on in the frame of the HyMeX project (www.hymex.org), with the aim of extending databases implemented in previous projects (e.g. Hydrate, 6th Framework Programme, www.hydrate.tesaf.unipd.it), and improving the understanding of flash flood formation in the Mediterranean.
Four floods have been documented from 2010 to 2012 by means of post-event field observations and analysis of hydrometeorological data_ Var Department (SE France), June 2010; Bacchiglione River basin (NE Italy), November 2010; Magra River basin (NW Italy), October 2011; Longano catchment (Sicily), November 2011. Flood magnitude in some catchment hit by these flash floods approaches maxima known in the Mediterranean region.
The studied event have permitted focusing on different features relevant for the assessment of flash flood response_
oinfluence of geological settings on flood response (Var Department);
omorphological changes of channel beds and recruitment and transport of large wood (Magra River basin);
ocomplex sediment dynamics and flood analysis in an urban context (Longano catchment).
The flood of November 2010 in the Bacchiglione River basin has been considered, although it does not show all distinctive attributes of flash floods, because it was most severe flood in the studied area since November 1966 and it is representative of increased flood risk due to land use changes occurred in the last decades (expansion of industrial and urban areas).
The contribution summarises the most relevant characteristics of the investigated events and outlines problems and perspective in post-event documentation of flash floods.
Marchi L., Tecca P.R., 2013, Debris-Flow Monitoring in Italy,
Dating Torrential Processes on Fans and Cones, edited by M. Schneuwly-Bollschweiler; M. Stoffel; F. Rudolf-Miklau, pp. 309–318. DORDRECHT_ SPRINGER, 2013,
Abstract
Monitoring of debris flows, aimed at assessing their physical parameters, is important both for theoretical ...
Monitoring of debris flows, aimed at assessing their physical parameters, is important both for theoretical and practical purposes, such as the determination of their rheological behaviour and the calibration of mathematical models, as well as for planning countermeasures and designing warning systems.
Automated monitoring systems are needed to collect data on debris flows; different types of sensor systems, designed both for debris flow detection and warning, and for research have been installed in several countries.
This paper presents Italian research experiences in two instrumented sites of the eastern Italian Alps_ Moscardo Torrent and Acquabona, where debris flow monitoring systems were set up since 1990 and 1997 respectively.
Bossi G., Frigerio S., Mantovani M., Marcato G., Pasuto A., 2013, Convenzione tra il comune di Cortina d’Ampezzo ed il Consiglio Nazionale delle Ricerche – Istituto Di Ricerca per la Protezione Idrogeologica Unita’ di Padova per lo studio dei movimenti franosi in prossimità degli abitati di Lacedel, Val e Mortisa in Cortina d’Ampezzo,
2013,
Munari S.; Bossi G.; D'Agostino V.; Pozza E.; Bettella A.; Cola S., 2013, Calibration of a SPH model for the numerical analysis of mud-flowrun-out: the case of the Rotolon torrent in Italy,
EGU General Assembly 2013, Wien, 2013,
Aaron Micallef a, b,
Federica Foglini c,
Timothy Le Bas d,
Lorenzo Angeletti c,
Vittorio Maselli c,
Alessandro Pasuto e,
Marco Taviani c, f, 2013, The submerged paleolandscape of the Maltese Islands_ Morphology, evolution and relation to Quaternary environmental change,
Marine geology (Print) 335 (2013): 129–147.,
Pia Rosella Tecca, Andrea Maria Deganutti, Rinaldo Genevois, Marco Dal Prà, 2013, Field study and bidimensional numerical simulation of runout and deposition of La Marogna rockslide (Vicenza, Italy),
International Conference on Vajont 1963-2013. Thoughts and analyses after 50 years since the catastrophic landslide, pp. 201–210, Padova - Italia, 8-10 Ottobre 2013,
Abstract
The study of ancient major rock slope instabilities may help in the detection of the ...
The study of ancient major rock slope instabilities may help in the detection of the conditions leading to their development, so
that consequences and possible prevention and mitigation actions can be envisaged.
In this paper, numerical studies have been carried out to recognize the behavior of a rock slope and the kinematics of a rock
slide/avalanche in the north-eastern Italian Alps. The "La Marogna" rock avalanche, in the Vicenza Province (Venetian Pre-Alps,
North-Eastern Italy), with a volume of about 17*106 m3 still partially dams the narrow valley of the Astico River. Geomorphological
investigations highlight that the whole rock avalanche mass is formed by two distinct overlapping bodies and that apparent poor
stability conditions characterize the slope above the present main scarp.
In order to get indications about triggering factors and present stability conditions, a representative engineering geological
model has been built and analyses of the triggering conditions have been performed using the bi-dimensional continuum (FLAC) and
discontinuum (UDEC) codes UDEC on the re-constructed original slope profile. Different situations have been simulated for gaining
a better understanding of the effect of static and dynamic loads on the modeled rock slope.
The numerical results indicate that the effect of a contemporary dynamic loading and joint friction decrease results in the
instability of a rock mass limited at its bottom by both bedding and a pre-existing discontinuity.
Cavalli M., Trevisani S., Comiti F, Marchi L., 2013, Geomorphometric assessment of spatial sediment connectivity in small Alpine catchments,
Geomorphology (Amst.) 188 (2013): 31–41. doi_10.1016/j.geomorph.2012.05.007,
DOI: 10.1016%2Fj.geomorph.2012.05.007
Abstract
Complex and rugged topography induces large variations in erosion and sediment delivery in the headwaters ...
Complex and rugged topography induces large variations in erosion and sediment delivery in the headwaters of alpine catchments. An effective connection of hillslopes with the channel network results in highly efficient sediment transfer processes, such as debris flows. In contrast, morphological conditions producing decoupling of hillslopes from channels (e.g. glacial cirques) may exclude large areas of the catchment from sediment delivery to its lower parts. Moreover, an efficient connection between hillslopes and channel network does not always ensure an effective downstream transfer of sediment. Low-slope channel reaches (e.g. in hanging valleys) cause sediment deposition, which often results in changes of the sediment transport processes, typically from debris flow to streamflow with low bedload and suspended load rates. The availability of high-resolution digital terrain models, such as those derived from aerial LiDAR, improves our capability to quantify the topographic controls on sediment connectivity. A geomorphometric index, based on the approach by Borselli et al. (2008), was developed and applied to assess spatial sediment connectivity in two small catchments of the Italian Alps featuring contrasting morphological characteristics. The results of the geomorphometric analysis were checked against field evidences, showing good performance and thus potential usefulness of the index.
Goldin B., Cavalli M., Comiti F., Marchi L., 2013, Geomorphic change detection in small Alpine basins using LiDAR DTMs,
EGU General Assembly 2013, Vienna (Austria), 7-12 Aprile 2013,
Lucìa A., Comiti F., Borga M., Cavalli M., Marchi L., 2013, Large wood recruitment and transport during a severe flash flood in North-western Italy,
EGU General Assembly 2013, Vienna (Austria), 7-12 Aprile 2013,
Okamoto A., Uchida T., Hayashi S.I., Cavalli M., Marcato G., Pasuto A., 2013, Assessing of soil loss caused by active landsliding at the catchment scale_ comparison of two different methods in Japan and Italy,
8th International conference (AIG) on Geomorphology., pp. 648, Parigi (Francia), 27-31 Agosto 2013,
Abstract
Sediment transport rate in mountainousstreams is strongly controlled by sediment yield due to erosion and
landslides, ...
Sediment transport rate in mountainousstreams is strongly controlled by sediment yield due to erosion and
landslides, therefore giving a valuable contribution in the definition of the state of activity and potential impact of
active landslides. However, a comprehensive monitoring system of sediment dynamics is usually very expensive,
time consuming and above all technologically complicated. In this paper we compare two different approaches
used in two test sites in Japan and Italy.
The difficulties in directly monitoring of traction processes have been widely recognized and prompted research
towards indirect monitoring techniques, including acoustic and seismic methods.Recently, a new method to
indirectly measure the volume of bedload transport from sound pressure data, provided by hydrophones, was
proposed. The preliminary results of the measurement campaigns in the Japanese test site will be here
presented showing that the bedload transport rate evaluated by hydrophone fit very well with the data gathered
by direct sampling for both long- and short-term time spans.
Inthe Italian test site, a geomorphometric approach, consisting in computing the difference of DTMs derived from
LiDAR data acquired at different times, has been carried out at catchment scale helping assessing the loss of soil
caused by erosion processes and in the identification of areas of sediment deposition during a specified time
span.This approach is suitable for the study of processes with higher magnitude than sediment transport causing
morphological variations higher than the propagated DTMs errors (i.e. debris flow).
The possible integration of these approaches can cover a wide range of sediment transport processes (from
suspended sediment to debris flow) that affect mountain basins. Therefore, the resultsso far obtained clearly
show that these analyses can be functional in establishing a comprehensive management plan for a sustainable
land use, and in designing of mitigation works.
Crema S., Cavalli M., Macconi P., Marchi L., 2013, Regional-scale debris-flow modelization for hazard mapping in alpine basins using a high-resolution DTM and events geodatabase,
8th International conference (AIG) on Geomorphology., pp. 682, Parigi (Francia), 27-31 Agosto 2013,
Abstract
A very detailed geodatabase of floods, landslides and debris flows is available and kept up ...
A very detailed geodatabase of floods, landslides and debris flows is available and kept up to date for the
territory of the Autonomous Province of Bolzano, in northeastern Italy (7400 km2). The database is fed by field
surveys carried out after the occurrence of instability phenomena and reports locations and attributes of the
events for the last 15 years. The on-site analysis grants the gathering of important information and
documentation resulting from field measurements and interviews to witnesses of the events. Particular attention
is paid to the recognition of location, magnitude and path of landslides and debris flows.
Data on shallow landslide locations and debris-flow initiation sites have provided the input to a regional-scale
debris flow model aimed at the assessment of debris flow paths and inundation areas. A simple mass
propagation model based on topographic attributes (Huggel et al., 2003) has been applied to simulate mass
movement phenomena for selected basins using initiation sites listed in the regional database. In the model,
debris-flow propagation is given in probability-related values representing the hazard potential for the selected
locations. All the simulations have been carried out using a high-resolution (2.5m) LiDAR-derived Digital Terrain
Model (DTM).
The combination of a georeferenced database of landslides and debris flows and a simple topography-based
model constitutes therefore a reliable tool for a fast and preliminary debris-flow hazard estimate, assessment and
mapping.
References_ Huggel C, Kääb A, Haeberli W, Krummenacher B. 2003. Regional-scale GIS-models for
assessment of hazards from glacier lake outbursts_ Evaluation and application in the Swiss Alps. Natural
Hazards and Earth System Sciences 3(6):647-662.
Bossi G., Cavalli M., Quan Luna B., Frigerio S., Mantovani M., Marcato G., Schenato L., Pasuto A, 2013, Multi temporal LiDAR-DTMs as a tool for modeling a complex landslide_ a case study in the Small Dolomites (Rotolon catchment – Italy),
8th International conference (AIG) on Geomorphology., pp. 682, Parigi (Francia), 27-31 Agosto 2013,
Abstract
The geomorphological change detection through the comparison of repeated topographic surveys is a recent
approach that ...
The geomorphological change detection through the comparison of repeated topographic surveys is a recent
approach that greatly benefits from the latest developments in topographical data acquisition techniques. Among
them, airborne LiDAR makes the monitoring of geomorphological changes a more reliable and accurate
approach for natural hazard and risk management. In this study, the analysis of multi temporal LiDAR-DTMs
acquired just before and after a complex landslide event (4th November 2010) in the Rotolon catchment (Small
Dolomites, Italy), was used to set up the initial condition for the application of a dynamic model.
The 2010 event detached a mass of 320.000 m3 from the south slope of Mt. Rotolon partially evolving in a debris
flow that stretched for 4.5 km threatening some villages. Pre- and post-event DTMs derived from LiDAR with 2 m
resolution were available. The comparison between the DTMs was carried out considering the error propagation.
The resulting differential DTM was analyzed in order to identify erosion and depositional areas related to the
event and to quantify them in terms of volume.
The knowledge of the dynamics of the phenomenon allowed to back-analyze the event with a dynamic numerical
3D model. DAN3D code was selected because it allows to modify the rheology and the parameters of the moving
mass during the run-out. This behaviour was observed along the path of the debris-flow where the mobilized
mass encountered rheological modifications due to the hydric contribution of tributary streams and the
entrainment of eroded material. Considering these aspects a sound simulation of the 2010 event was computed.
Nowadays some portions of Mt. Rotolon flank are still moving and showing precursor signs of detachment. The
same soil parameters used in the back-analysis model were used to simulate the run-out for three possible
landslides flows allowing to generate reliable risk scenarios that could be used for creating civil defense
emergency plans.
Goldin B., Cavalli M., Brardinoni F., Comiti F., Marchi L., 2013, Geomorphic change detection using LiDAR DTMs in two small basins of the Italian Alps.,
8th International conference (AIG) on Geomorphology., pp. 1051, Parigi (Francia), 27-31 Agosto 2013,
Abstract
The description and quantification of landscape changes as modulated by geomorphic processes, at different
spatial and ...
The description and quantification of landscape changes as modulated by geomorphic processes, at different
spatial and temporal scales, constitute the core of modern geomorphic research. The high resolution and
accuracy of currently available airborne digital terrain models (DTMs) allow the development of new methods for
the quantitative monitoring of geomorphic changes. In this context, DTM of difference (DoD), which can be
created by subtracting one elevation model from another, represents a convenient way to estimate volumetric
changes across landscape components between successive topographic surveys.
In this contribution we quantify the topographic variations associated with the activity of rapid geomorphic
processes (e.g., debris slides and debris flows) in Gadria and Strimm catchments, two adjacent basins, covering
a total area of 14.7 km2, in the Eastern Italian Alps. To this purpose we perform DoD on two LiDAR-derived
DTMs (2 m resolution), acquired respectively in the summer of 2006 and 2011, applying a fuzzy logic-based
method (Wheaton et al., 2010) which considers the uncertainty in the surface representation of the topographic
data.
Results indicate that shallow rapid failures and channelized processes such as debris flows and debris floods
have been by far the dominant processes in both basins over the study period. In particular, we are able to track
the effects of a debris-flow event (July 12th 2010) originating on the western slopes of Strimm basin and that has
been estimated to transport 15,000 m3 of sediment down to the confluence with Gadria Creek. Not surprisingly,
upland terrain characterized by subdued topography and dominated by slow periglacial processes does not
exhibit any appreciable change.
Reference_ Wheaton J.M., Brasington J., Darby S. E., Shear D. A., 2010. Accounting for uncertainty in DTMs
from repeat topographic surveys_ improved sediment budges. Earth Surface Processes and Landforms, 35, 136-
156.
