The Geomorphic Units survey and classification System (GUS) has been developed for the survey and... more The Geomorphic Units survey and classification System (GUS) has been developed for the survey and classification of geomorphic units in streams and rivers, suitable to integrate the hydromorphological assessment at the reach scale (e.g. the Morphological Quality Index, MQI), and therefore to better establish links between hydromorphological conditions at the reach scale, characteristic geomorphic units and related biological conditions. The system includes 3 different spatial scales (i.e. Macro-units, Units, Sub-units) organized in 3 spatial contexts (i.e. Instream, Marginal, Floodplain) and is structured in 3 levels of description (i.e. Broad, Base, Detailed). At each level, different specific information is collected: from the simple census of units and their number, to the measurement of units size and the survey of specific unit characteristics (e.g. sediment, hydrology, vegetation). The method is applied by combining remote sensing analysis and field survey, according to the sp...
Este estudio reporta las cantidades de material leñoso de gran tamaño (large woody debris o LWD) ... more Este estudio reporta las cantidades de material leñoso de gran tamaño (large woody debris o LWD) y los efectos asociados sobre la morfología del cauce y la hidráulica del flujo en dos cuencas de montaña de la zona “templada-cálida con lluvias invernales” de la Cordillera de los Andes, en Chile. Las cuencas analizadas del río Toro y del torrente Tres Arroyos (área de drenaje de 9 y de 11 km2, respectivamente) se ubican en la Región de la Araucanía, Chile y se caracterizan por una cobertura forestal de bosques nativos de Nothofagus y Araucaria. Cantidad, características y dimensiones de los residuos leñosos (>10 cm de diámetro, >1 m de largo) fueron examinados en los canales, así como sus efectos sobre la morfología del cauce, sobre su hidráulica y sobre el almacenamiento de sedimento; se realizó además, un monitoreo del desplazamiento de los troncos durante un periodo de un año para determinar el grado de movilidad de las piezas leñosas. Los resultados demuestran que existen gr...
The research reported in this paper employs flume experiments to investigate the potential effect... more The research reported in this paper employs flume experiments to investigate the potential effects of living vegetation and large wood on river morphology, specifically aiming to explore how different wood input and vegetation scenarios impact channel patterns and dynamics. We used a mobile bed laboratory flume, divided into three parallel channels (1.7 m wide, 10 m long) filled with uniform sand to reproduce braided networks subject to a series of cycles of flooding, wood input, and vegetation growth. Temporal evolution of river configuration (in terms of the braiding index), vegetation establishment and erosion, and wood deposition amount and pattern was recorded in a series of vertical images. The experiments reproduced many forms and processes that have been observed in the field, from scattered logs in unvegetated, dynamic braided channels, to large wood jams associated with river bars and bends in vegetated, stable, single thread rivers. Results showed that the inclusion of vegetation in the experiments changes wood dynamics, in terms of both the quantity that is stored and the depositional patterns that develop. Vegetated banks increased channel stability, reducing lateral erosion and the number of active channels. This promoted the formation of stable wood jams, where logs accumulated continuously at the same locations during subsequent floods, reinforcing their effect on river morphology. The feasibility of studying these processes in a controlled environment opens new possibilities for disentangling the complex linkages in the biogeomorphological evolution of the fluvial system and thus for promoting improved scientific understanding.
In formerly glaciated mountain settings, Pleistocene glaciations are responsible for profound spa... more In formerly glaciated mountain settings, Pleistocene glaciations are responsible for profound spatial reorganization of the landscape structure. By imposing local channel slope and the degree of hillslope-channel connectivity, glacial macro-forms can exert first-order controls on the downstream strength and continuity of the coarse sediment cascade. To estimate quantitatively these controls we trace bedload transport for three years along the Strimm Creek, Eastern Italian Alps. Specifically, we monitor the travel distance of 490 PIT-tagged particles (<i>b</i> axis: 23–229 mm; weight: 83–6525 g) at two contrasting sites: Upper Strimm Creek (US; 4 km<sup>2</sup>), which flows through a fluvially-dominated hanging valley, and Lower Strimm Creek (LS; 7.5 km<sup>2</sup>), located downstream, in a relict glacial trough where it experiences periodic colluvial sediment inputs from lateral tributaries. Tracer positioning within the streambed is periodicall...
Snow-dominated and glacierized catchments are important sources of fresh water for biological com... more Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for populations living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater, streamflow and groundwater is critical for natural risk assessment and mitigation as well as for effective water resource management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and groundwater and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt, spring and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important end-members for stream runoff during late spring, su...
Engineering Geology for Society and Territory - Volume 3, 2014
ABSTRACT The estimation of debris-flow volume is a fundamental task for the design of any hazard ... more ABSTRACT The estimation of debris-flow volume is a fundamental task for the design of any hazard mitigation intervention in a mountain channel. The estimation may be carried out before the occurrence of a debris flow through methodologies aimed at assessing the debris potential in the basin. It can be carried out through instrumentation deployed along the torrent (stage sensors, geophones, etc.). Finally, volume estimation may be performed after the occurrence of the phenomenon, surveying the deposits left in the channel, in a possible retention basin or on the fan. The surveys can be carried out through a conventional topographic survey, through a terrestrial laser scanner (TLS), by photogrammetric techniques, etc.. Each method delivers approximated results, due to different reasons. A systematic comparison of the results of these different estimation procedures, carried out simultaneously in the same catchment, might help to better understand their advantages and limitations, to improve their output and to validate and standardize the respective methodologies. An European Territorial Cooperation project, named SedAlp, has been recently funded by the Alpine Space programme. An important focus of the project is on methods and data collection on sediment transport. In this context, one of the activities that is taking place in a pilot area consists in the comparison of the different methods and procedures for debris-flow volume estimation.
Quantifying sediment transport in small mountain basins is of great relevance to assess the morph... more Quantifying sediment transport in small mountain basins is of great relevance to assess the morphological and ecological dynamics of the entire channel network and to predict flood hazards. In high-elevation, glacierized basins, seasonal variability in sediment transport is dramatic, but despite the relevance of such basins in many regions worldwide, very few investigations have tried to quantify it. Since direct methods to assess bedload transport are time consuming and practically challenging at high flows, indirect surrogate methods, allowing continuous measurements over time, are highly desirable. Yet, these methods require calibration to provide reliable estimations. The present research focused on the calibration of an acoustic pipe sensor in the recently established (spring 2011) monitoring station in the Saldur basin, a high-elevation glacierized watershed in the Eastern Italian Alps. The acoustic pipe signal (which is amplified through 6 channels having different gains) was calibrated against samples collected over 26 sampling periods bedload traps along a cross-section 12 m upstream of the pipe. Samples were collected from June to August 2011 during daily discharge fluctuations (ranging from 1.40 to 3.63 m 3 s-1) due to snow-and glacier-melt, featuring very different bedload rates (up to 0.14 kg s-1 m-1). In order to calibrate the pipe sensor signal, the average number of impulses was plotted against the corresponding unit bedload rates for the associated bedload sampling periods. As expected, the signal from the two most sensitive channels of the acoustic sensor resulted dampened even at low discharges, and thus could not be used for calibration and bedload assessment. Instead, power laws (R 2 from 0.76 to 0.92) relating the number of impulses per minute to unit bedload rate were obtained using channels having intermediate and low sensitivity, with higher correlations associated with the less sensitive channels. *Manuscript Click here to download Manuscript: Catena 2990-Manuscript.doc Click here to view linked References
ABSTRACT River degradation and thus necessity for restoration are major issues worldwide. However... more ABSTRACT River degradation and thus necessity for restoration are major issues worldwide. However, adequate methodologies to assess morphological variations linked to these actions and the morphological success of restoration interventions are still to be determined. The Ahr River (South Tyrol, Italian Alps) was characterized until the mid-twentieth century by an anabranching and meandering pattern, but starting from the 1960s it underwent intense channel degradation in terms of narrowing, incision, and floodplain disconnection. In the period 2003–2011, several reaches of the Ahr River were restored by widening and raising the channel bed. The planimetric changes that occurred historically in the Ahr River were determined by the interpretation of 10 maps and aerial photos covering the period 1820–2011. The estimation of the incision that occurred during the degradation phase was assessed by the difference in elevation between gravel surfaces, whereas the changes introduced by restoration interventions in two reaches were evaluated through the comparison of topographic cross sections surveyed in year 2000 and a high-resolution bathymetric LiDAR survey flown in late 2012. The MQI (Morphological Quality Index) was applied to different reaches in order to test how assessment methodologies respond to degradation and restoration actions. The combined analysis of planform and vertical changes indicates that gravel mining has been the largest pressure for the river, but a change in sediment/flow regimes probably led to the channel adjustments that occurred during the early twentieth century. The restoration measures have locally increased channel width, elevation, and morphometrical diversity compared to the unrestored reaches, as well as the morphological quality assessed by MQI. However, the extent of the modifications brought about by restoration works differs between the two restored reaches, pointing out the need for a quantitative analysis of the historical evolution of each river reach before designing and implementing restoration actions and to the necessity to monitor the subsequent morphological adjustments.
Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II, 2008
This paper presents the evidence gathered during a post-flood survey in a Slovenian mountain basi... more This paper presents the evidence gathered during a post-flood survey in a Slovenian mountain basin (Davča basin, drainage area of 32 km 2) following the catastrophic flood of September 2007. Channel avulsion, debris flows and landslides delivered large volumes of wood into the channel, and massive wood accumulations were found at the basin outlet. Wood-induced dam-break flows were therefore hypothesised to be responsible for most of the damages. Field observations and approximate discharge estimations indicate that the damages suffered in the Davča basin can be attributed to excessive wood load only to a limited extent, and that the critical factors were narrow road crossings which acted as traps for sediment and wood.
Quantifying sediment transport in small mountain basins is of great relevance to assess the morph... more Quantifying sediment transport in small mountain basins is of great relevance to assess the morphological and ecological dynamics of the entire channel network and to predict flood hazards. In high-elevation, glacierized basins, seasonal variability in sediment transport is dramatic, but despite the relevance of such basins in many regions worldwide, very few investigations have tried to quantify it. Since direct methods to assess bedload transport are time consuming and practically challenging at high flows, indirect surrogate methods, allowing continuous measurements over time, are highly desirable. Yet, these methods require calibration to provide reliable estimations. The present research focused on the calibration of an acoustic pipe sensor in the recently established (spring 2011) monitoring station in the Saldur basin, a high-elevation glacierized watershed in the Eastern Italian Alps. The acoustic pipe signal (which is amplified through 6 channels having different gains) was calibrated against samples collected over 26 sampling periods bedload traps along a cross-section 12 m upstream of the pipe. Samples were collected from June to August 2011 during daily discharge fluctuations (ranging from 1.40 to 3.63 m 3 s-1) due to snow-and glacier-melt, featuring very different bedload rates (up to 0.14 kg s-1 m-1). In order to calibrate the pipe sensor signal, the average number of impulses was plotted against the corresponding unit bedload rates for the associated bedload sampling periods. As expected, the signal from the two most sensitive channels of the acoustic sensor resulted dampened even at low discharges, and thus could not be used for calibration and bedload assessment. Instead, power laws (R 2 from 0.76 to 0.92) relating the number of impulses per minute to unit bedload rate were obtained using channels having intermediate and low sensitivity, with higher correlations associated with the less sensitive channels. *Manuscript Click here to download Manuscript: Catena 2990-Manuscript.doc Click here to view linked References
Snow-dominated and glacierized catchments are important sources of fresh water for biological com... more Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for populations living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater, streamflow and groundwater is critical for natural risk assessment and mitigation as well as for effective water resource management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and groundwater and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt, spring and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important endmembers for stream runoff during late spring, summer and early fall. The temporal variability of the tracer concentration suggested that stream water was dominated by snowmelt at the beginning of the melting season (May-June), by a mixture of snowmelt and glacier melt during midsummer (Julyearly August), and by glacier melt during the end of the summer (end of August-September). The same seasonal pattern observed in streamflow was also evident for groundwater, with the highest electrical conductivity and least negative isotopic values found during cold or relatively less warm periods, when the melt of snowpack and ice was limited. Particularly, the application of a two-component mixing model to data from different springs showed that the snowmelt contribution to groundwater recharge varied between 21 % (±3 %) and 93 % (±1 %) over the season, and the overall contribution during the three study years ranged between 58 % (±24 %) and 72 % (±19 %). These results provided new insights into the isotopic characterization of the study catchment presenting further understanding of the spatio-temporal variability of the main water sources contributing to runoff.
Die Bodenkultur 93 64 (3-4) 2013 2 Study area and methodology Experimental data were collected be... more Die Bodenkultur 93 64 (3-4) 2013 2 Study area and methodology Experimental data were collected between April and October 2011 in the Saldur catchment, Eastern Italian Alps (area: 62 km 2 , elevation range: 1600-3700 m a.s.l., Fig. 1) that hosts a small glacier (2.8 km²) in its upper portion. Water stage measured by pressure transducers at the catchment outlet and at two locations (LSG: Lower Stream Gauge, at 2150 m a.s.l., drainage area 20 km 2 ; USG: Upper Stream Gauge, at 2340 m a.s.l., drainage area 11 km 2) was
The Geomorphic Units survey and classification System (GUS) has been developed for the survey and... more The Geomorphic Units survey and classification System (GUS) has been developed for the survey and classification of geomorphic units in streams and rivers, suitable to integrate the hydromorphological assessment at the reach scale (e.g. the Morphological Quality Index, MQI), and therefore to better establish links between hydromorphological conditions at the reach scale, characteristic geomorphic units and related biological conditions. The system includes 3 different spatial scales (i.e. Macro-units, Units, Sub-units) organized in 3 spatial contexts (i.e. Instream, Marginal, Floodplain) and is structured in 3 levels of description (i.e. Broad, Base, Detailed). At each level, different specific information is collected: from the simple census of units and their number, to the measurement of units size and the survey of specific unit characteristics (e.g. sediment, hydrology, vegetation). The method is applied by combining remote sensing analysis and field survey, according to the sp...
Este estudio reporta las cantidades de material leñoso de gran tamaño (large woody debris o LWD) ... more Este estudio reporta las cantidades de material leñoso de gran tamaño (large woody debris o LWD) y los efectos asociados sobre la morfología del cauce y la hidráulica del flujo en dos cuencas de montaña de la zona “templada-cálida con lluvias invernales” de la Cordillera de los Andes, en Chile. Las cuencas analizadas del río Toro y del torrente Tres Arroyos (área de drenaje de 9 y de 11 km2, respectivamente) se ubican en la Región de la Araucanía, Chile y se caracterizan por una cobertura forestal de bosques nativos de Nothofagus y Araucaria. Cantidad, características y dimensiones de los residuos leñosos (>10 cm de diámetro, >1 m de largo) fueron examinados en los canales, así como sus efectos sobre la morfología del cauce, sobre su hidráulica y sobre el almacenamiento de sedimento; se realizó además, un monitoreo del desplazamiento de los troncos durante un periodo de un año para determinar el grado de movilidad de las piezas leñosas. Los resultados demuestran que existen gr...
The research reported in this paper employs flume experiments to investigate the potential effect... more The research reported in this paper employs flume experiments to investigate the potential effects of living vegetation and large wood on river morphology, specifically aiming to explore how different wood input and vegetation scenarios impact channel patterns and dynamics. We used a mobile bed laboratory flume, divided into three parallel channels (1.7 m wide, 10 m long) filled with uniform sand to reproduce braided networks subject to a series of cycles of flooding, wood input, and vegetation growth. Temporal evolution of river configuration (in terms of the braiding index), vegetation establishment and erosion, and wood deposition amount and pattern was recorded in a series of vertical images. The experiments reproduced many forms and processes that have been observed in the field, from scattered logs in unvegetated, dynamic braided channels, to large wood jams associated with river bars and bends in vegetated, stable, single thread rivers. Results showed that the inclusion of vegetation in the experiments changes wood dynamics, in terms of both the quantity that is stored and the depositional patterns that develop. Vegetated banks increased channel stability, reducing lateral erosion and the number of active channels. This promoted the formation of stable wood jams, where logs accumulated continuously at the same locations during subsequent floods, reinforcing their effect on river morphology. The feasibility of studying these processes in a controlled environment opens new possibilities for disentangling the complex linkages in the biogeomorphological evolution of the fluvial system and thus for promoting improved scientific understanding.
In formerly glaciated mountain settings, Pleistocene glaciations are responsible for profound spa... more In formerly glaciated mountain settings, Pleistocene glaciations are responsible for profound spatial reorganization of the landscape structure. By imposing local channel slope and the degree of hillslope-channel connectivity, glacial macro-forms can exert first-order controls on the downstream strength and continuity of the coarse sediment cascade. To estimate quantitatively these controls we trace bedload transport for three years along the Strimm Creek, Eastern Italian Alps. Specifically, we monitor the travel distance of 490 PIT-tagged particles (<i>b</i> axis: 23–229 mm; weight: 83–6525 g) at two contrasting sites: Upper Strimm Creek (US; 4 km<sup>2</sup>), which flows through a fluvially-dominated hanging valley, and Lower Strimm Creek (LS; 7.5 km<sup>2</sup>), located downstream, in a relict glacial trough where it experiences periodic colluvial sediment inputs from lateral tributaries. Tracer positioning within the streambed is periodicall...
Snow-dominated and glacierized catchments are important sources of fresh water for biological com... more Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for populations living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater, streamflow and groundwater is critical for natural risk assessment and mitigation as well as for effective water resource management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and groundwater and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt, spring and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important end-members for stream runoff during late spring, su...
Engineering Geology for Society and Territory - Volume 3, 2014
ABSTRACT The estimation of debris-flow volume is a fundamental task for the design of any hazard ... more ABSTRACT The estimation of debris-flow volume is a fundamental task for the design of any hazard mitigation intervention in a mountain channel. The estimation may be carried out before the occurrence of a debris flow through methodologies aimed at assessing the debris potential in the basin. It can be carried out through instrumentation deployed along the torrent (stage sensors, geophones, etc.). Finally, volume estimation may be performed after the occurrence of the phenomenon, surveying the deposits left in the channel, in a possible retention basin or on the fan. The surveys can be carried out through a conventional topographic survey, through a terrestrial laser scanner (TLS), by photogrammetric techniques, etc.. Each method delivers approximated results, due to different reasons. A systematic comparison of the results of these different estimation procedures, carried out simultaneously in the same catchment, might help to better understand their advantages and limitations, to improve their output and to validate and standardize the respective methodologies. An European Territorial Cooperation project, named SedAlp, has been recently funded by the Alpine Space programme. An important focus of the project is on methods and data collection on sediment transport. In this context, one of the activities that is taking place in a pilot area consists in the comparison of the different methods and procedures for debris-flow volume estimation.
Quantifying sediment transport in small mountain basins is of great relevance to assess the morph... more Quantifying sediment transport in small mountain basins is of great relevance to assess the morphological and ecological dynamics of the entire channel network and to predict flood hazards. In high-elevation, glacierized basins, seasonal variability in sediment transport is dramatic, but despite the relevance of such basins in many regions worldwide, very few investigations have tried to quantify it. Since direct methods to assess bedload transport are time consuming and practically challenging at high flows, indirect surrogate methods, allowing continuous measurements over time, are highly desirable. Yet, these methods require calibration to provide reliable estimations. The present research focused on the calibration of an acoustic pipe sensor in the recently established (spring 2011) monitoring station in the Saldur basin, a high-elevation glacierized watershed in the Eastern Italian Alps. The acoustic pipe signal (which is amplified through 6 channels having different gains) was calibrated against samples collected over 26 sampling periods bedload traps along a cross-section 12 m upstream of the pipe. Samples were collected from June to August 2011 during daily discharge fluctuations (ranging from 1.40 to 3.63 m 3 s-1) due to snow-and glacier-melt, featuring very different bedload rates (up to 0.14 kg s-1 m-1). In order to calibrate the pipe sensor signal, the average number of impulses was plotted against the corresponding unit bedload rates for the associated bedload sampling periods. As expected, the signal from the two most sensitive channels of the acoustic sensor resulted dampened even at low discharges, and thus could not be used for calibration and bedload assessment. Instead, power laws (R 2 from 0.76 to 0.92) relating the number of impulses per minute to unit bedload rate were obtained using channels having intermediate and low sensitivity, with higher correlations associated with the less sensitive channels. *Manuscript Click here to download Manuscript: Catena 2990-Manuscript.doc Click here to view linked References
ABSTRACT River degradation and thus necessity for restoration are major issues worldwide. However... more ABSTRACT River degradation and thus necessity for restoration are major issues worldwide. However, adequate methodologies to assess morphological variations linked to these actions and the morphological success of restoration interventions are still to be determined. The Ahr River (South Tyrol, Italian Alps) was characterized until the mid-twentieth century by an anabranching and meandering pattern, but starting from the 1960s it underwent intense channel degradation in terms of narrowing, incision, and floodplain disconnection. In the period 2003–2011, several reaches of the Ahr River were restored by widening and raising the channel bed. The planimetric changes that occurred historically in the Ahr River were determined by the interpretation of 10 maps and aerial photos covering the period 1820–2011. The estimation of the incision that occurred during the degradation phase was assessed by the difference in elevation between gravel surfaces, whereas the changes introduced by restoration interventions in two reaches were evaluated through the comparison of topographic cross sections surveyed in year 2000 and a high-resolution bathymetric LiDAR survey flown in late 2012. The MQI (Morphological Quality Index) was applied to different reaches in order to test how assessment methodologies respond to degradation and restoration actions. The combined analysis of planform and vertical changes indicates that gravel mining has been the largest pressure for the river, but a change in sediment/flow regimes probably led to the channel adjustments that occurred during the early twentieth century. The restoration measures have locally increased channel width, elevation, and morphometrical diversity compared to the unrestored reaches, as well as the morphological quality assessed by MQI. However, the extent of the modifications brought about by restoration works differs between the two restored reaches, pointing out the need for a quantitative analysis of the historical evolution of each river reach before designing and implementing restoration actions and to the necessity to monitor the subsequent morphological adjustments.
Monitoring, Simulation, Prevention and Remediation of Dense Debris Flows II, 2008
This paper presents the evidence gathered during a post-flood survey in a Slovenian mountain basi... more This paper presents the evidence gathered during a post-flood survey in a Slovenian mountain basin (Davča basin, drainage area of 32 km 2) following the catastrophic flood of September 2007. Channel avulsion, debris flows and landslides delivered large volumes of wood into the channel, and massive wood accumulations were found at the basin outlet. Wood-induced dam-break flows were therefore hypothesised to be responsible for most of the damages. Field observations and approximate discharge estimations indicate that the damages suffered in the Davča basin can be attributed to excessive wood load only to a limited extent, and that the critical factors were narrow road crossings which acted as traps for sediment and wood.
Quantifying sediment transport in small mountain basins is of great relevance to assess the morph... more Quantifying sediment transport in small mountain basins is of great relevance to assess the morphological and ecological dynamics of the entire channel network and to predict flood hazards. In high-elevation, glacierized basins, seasonal variability in sediment transport is dramatic, but despite the relevance of such basins in many regions worldwide, very few investigations have tried to quantify it. Since direct methods to assess bedload transport are time consuming and practically challenging at high flows, indirect surrogate methods, allowing continuous measurements over time, are highly desirable. Yet, these methods require calibration to provide reliable estimations. The present research focused on the calibration of an acoustic pipe sensor in the recently established (spring 2011) monitoring station in the Saldur basin, a high-elevation glacierized watershed in the Eastern Italian Alps. The acoustic pipe signal (which is amplified through 6 channels having different gains) was calibrated against samples collected over 26 sampling periods bedload traps along a cross-section 12 m upstream of the pipe. Samples were collected from June to August 2011 during daily discharge fluctuations (ranging from 1.40 to 3.63 m 3 s-1) due to snow-and glacier-melt, featuring very different bedload rates (up to 0.14 kg s-1 m-1). In order to calibrate the pipe sensor signal, the average number of impulses was plotted against the corresponding unit bedload rates for the associated bedload sampling periods. As expected, the signal from the two most sensitive channels of the acoustic sensor resulted dampened even at low discharges, and thus could not be used for calibration and bedload assessment. Instead, power laws (R 2 from 0.76 to 0.92) relating the number of impulses per minute to unit bedload rate were obtained using channels having intermediate and low sensitivity, with higher correlations associated with the less sensitive channels. *Manuscript Click here to download Manuscript: Catena 2990-Manuscript.doc Click here to view linked References
Snow-dominated and glacierized catchments are important sources of fresh water for biological com... more Snow-dominated and glacierized catchments are important sources of fresh water for biological communities and for populations living in mountain valleys. Gaining a better understanding of the runoff origin and of the hydrological interactions between meltwater, streamflow and groundwater is critical for natural risk assessment and mitigation as well as for effective water resource management in mountain regions. This study is based on the use of stable isotopes of water and electrical conductivity as tracers to identify the water sources for runoff and groundwater and their seasonal variability in a glacierized catchment in the Italian Alps. Samples were collected from rainfall, snow, snowmelt, ice melt, spring and stream water (from the main stream at different locations and from selected tributaries) in 2011, 2012 and 2013. The tracer-based mixing analysis revealed that, overall, snowmelt and glacier melt were the most important endmembers for stream runoff during late spring, summer and early fall. The temporal variability of the tracer concentration suggested that stream water was dominated by snowmelt at the beginning of the melting season (May-June), by a mixture of snowmelt and glacier melt during midsummer (Julyearly August), and by glacier melt during the end of the summer (end of August-September). The same seasonal pattern observed in streamflow was also evident for groundwater, with the highest electrical conductivity and least negative isotopic values found during cold or relatively less warm periods, when the melt of snowpack and ice was limited. Particularly, the application of a two-component mixing model to data from different springs showed that the snowmelt contribution to groundwater recharge varied between 21 % (±3 %) and 93 % (±1 %) over the season, and the overall contribution during the three study years ranged between 58 % (±24 %) and 72 % (±19 %). These results provided new insights into the isotopic characterization of the study catchment presenting further understanding of the spatio-temporal variability of the main water sources contributing to runoff.
Die Bodenkultur 93 64 (3-4) 2013 2 Study area and methodology Experimental data were collected be... more Die Bodenkultur 93 64 (3-4) 2013 2 Study area and methodology Experimental data were collected between April and October 2011 in the Saldur catchment, Eastern Italian Alps (area: 62 km 2 , elevation range: 1600-3700 m a.s.l., Fig. 1) that hosts a small glacier (2.8 km²) in its upper portion. Water stage measured by pressure transducers at the catchment outlet and at two locations (LSG: Lower Stream Gauge, at 2150 m a.s.l., drainage area 20 km 2 ; USG: Upper Stream Gauge, at 2340 m a.s.l., drainage area 11 km 2) was
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