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AN ESTIMATE OF THE SEDIMENTS VOLUME ENTRAINABLE BY DEBRIS FLOW ALONG STROBEL AND SOUTH PEZORÌES CHANNELS AT FIAMES (DOLOMITES, ITALY)
No full textThe area of Fiames is located on a narrow and flat valley, 2 km north to Cortina d’Ampezzo, and is bounded on the right side by the
Pomagagnon and Pezorìes peaks. At the transition between rock vertical cliffs and talus, about twenty debris channels originate and affect the
talus till the bottom of the valley. The Strobel and South Pezorìes channels were recently routed by debris flows in 2004 and 2006. Field surveys,
topographical and geo-morphological measurements were carried out to recognize the sediments volume that the debris flow can entrain during
triggering and routing phases. The estimate of the erodible sediment volume was obtained through the measurements of the geo-morphological
and sediments features of source areas including their locations (channel bank or bottom). The resultant estimate can help in the design of the
input debris flow hydrographs for dynamic modelling of debris flow and retain basins
Hydrologic response in the initiation area of the Dimai debris flow (Dolomites, Italian Alps)
No full textDebris flows are fast moving landslides of mixed water and poorly sorted debris (IVERSON, 1997; CRUDEN AND VARNES, 1996). Because of the high flow velocity, impact forces, and long runout, debris flows are commonly regarded as one of the most hazardous landslide types (JAKOB, 2005). The Dolomites region (NE Italian Alps) has one of the most frequent return intervals for large debris flows on the world (PASUTO AND SOLDATI, 2004; SKERMER AND VANDINE, 2005).
In the Dolomites the landscape is dominated by steep dolomite massifs rising up to 3300 m a.s.l. The rocky cliffs are connected to the bottom of alpine valleys by means of milder slopes where bedrock is covered by a thick debris talus, deposited in post-glacial climatic conditions. Debris flow channels are deeply incised in the talus slope and feeded by small headwater basins located on the cliffs (MARCHI AND TECCA, 1992; BERTI et alii, 199). These basins are typically very steep (45°-60° on the average) and mostly consist of exposed bedrock with no vegetation and almost absent soil cover.
During high intensity short duration thunderstorms, rainfall water is collected by the rocky watersheds as overland flow and trunk streams incised in bedrock, and quickly delivered to the talus cones. Most of this water infiltrates into the channel bed debris and flows downstream as subsurface stormflow. However, when the infiltration capacity of the streambed is exceeded, surface flow appears in the channel and debris flows are triggered by the progressive erosion of the loose bed debris (BERTI AND SIMONI, 2005).
Although this initiation mechanism has been widely recognized in the field (e.g. CANNON et alii, 2003), monitoring data describing the onset of channel runoff and the triggering process are still lacking. In this paper we describe the monitoring systems installed on a typical debris flow catchment of the Dolomites (Dimai basin, Cortina d’Ampezzo, Belluno), with the main aim of describing the hydrologic response in the initiation area
MONITARAGGIO DEI DEFLUSSI SUPERFICIALI IN UN CANALE ROCCIOSO INCISO SUL CAMPANILE DIMAI A FIAMES (CORTINA D'AMPEZZO, BL): ANALISI PRELIMINARI
No full textLe colate detritiche nella zona dolomitica sono innescate dai deflussi superficiali che discendono i canali incisi sulle pareti rocciose per movimentazione del materiale detritico giacente al piede di questi. Il monitoraggio dei deflussi superficiali è quindi di notevole importanza per lo studio di questi fenomeni di tipo impulsivo caratterizzati da un innesco difficilmente prevedibile in termini orari e spaziali. Il monitoraggio oltre a determinare le condizioni idrologiche associate alla generazione delle colate detritiche, permette la verifica e calibratura di modelli idrologici per la simulazione di fenomeni tipo flash floods. A partire dall'estate 2009, si è iniziato ad instrumentare l'area di Fiames, situata 2 km a nord di Cortina d’Ampezzo lungo la SS 51, con pluviometri e nel Luglio 2010 si è installata al piede del Campanile Dimai una stazione dotata di telecamere e sensori di pressione per monitorare i deflussi e l'eventuale generazione delle colate detritiche. L'analisi dei dati dei sensori di pressione per ogni evento di deflusso superficiale ha permesso di caratterizzare la risposta idrologica di un versante roccioso. Nell' Agosto 2011 è stato installato, 50 m a monte della stazione, uno stramazzo in parete sottile in un canale roccioso largo 1.65 m. Si è verificato un evento di precipitazione di carattere impulsivo (16.6 mm in 10 minuti) ed i valori di portata misurati sono stati confrontati con quelli simulati mediante un modello idrologico per flash floods
Monitoraggio dei deflussi in piccoli bacini dolomitici di alta quota e relativa modellazione idrologica
No full textCharacteristics of debris flows just downstream the initiation area on Punta Nera cliffs, Venetian Dolomites
No full textThe Piees de ra Mognes fan at the base of the Punta Nera cliffs, in the Venetian Dolomites (Italy), has been subject to debris flow activity for decades. Until recently, these debris flows never reached the National Road 51 on the valley bottom. Debris flows usually initiated at the base of an incised rocky channel in the Punta Nera cliffs where runoff is delivered to loose scree deposits of the fan. The main debris flow channel is strongly incised at the apex of the fan and splits into several minor channels at lower elevations. During the autumn 2014 and May 2016, two cliff collapses produced large debris deposits. Since then, the frequency of debris flows increased considerably because of the availability of debris deposits at very steep slope that lowered the runoff discharge needed for the debris flow initiation. In a few cases, debris flows that initiated in the rocky channel reached and interrupted the National Road 51, about 2 km downstream the well-known touristic village of Cortina d’Ampezzo. On July 2016, a monitoring station was placed at the beginning of the debris flow channel just downstream the base of the rocky channel. In the period between July and -September, the monitoring station recorded six debris flow events. Analysis of these data is used to describe the characteristics of debris flow initial routing. Moreover, we use video image analysis to investigate the velocity and depth of the surge from the 5 August 2016 event
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Runoff of small rocky headwater catchments: Field observations and hydrological modeling.
No full textIn dolomitic headwater catchments, intense rainstorms of short duration produce runoff discharges that often trigger debris
flows on the scree slopes at the base of rock cliffs. In order to measure these discharges, we placed a measuring facility at the outlet (elevation 1770 m a.s.l.) of a small,
rocky headwater catchment (area 0.032 km^2, average slope 320 % located in the Venetian Dolomites (North Eastern Italian Alps). The facility consists of an
approximately rectangular basin, ending with a sharp-crested weir. Six runoff events were recorded in the period 2011-2014, providing a unique opportunity for characterizing the
hydrological response of the catchment. The measured hydrographs display impulsive shapes, with an abrupt raise up to the peak, followed by a rapidly decreasing tail, until a
nearly constant plateau is eventually reached. This behavior can be simulated by means of a distributed hydrological model if the excess rainfall is
determined accurately. We show that using the Soil Conservation Service Curve-Number (SCS-CN) method and assuming a constant routing velocity invariably results in an
underestimated peak flow and a delayed peak time. A satisfactory prediction of the impulsive hydrograph shape including peak
value and timing is obtained only by combining the SCS-CN procedure with a simplified version of the Horton equation, and
simulating runoff routing along the channel network through a matched diffusivity kinematic wave model. The robustness of the proposed methodology is tested through a comparison between simulated
and observed timings of runoff or debris flow occurrence in two neighboring alpine basins
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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