<p>Risk mitigation for shallow slides and debris flows at a regional scale ... more <p>Risk mitigation for shallow slides and debris flows at a regional scale is a challenge. Landslide early warning systems (LEWS) are a helpful tool to anticipate the time and location of possible landslide events so that the authorities in charge of managing the landslide risk can plan their actions.</p><p>Traditionally, regional LEWS rely on rainfall information to asses if the landslide triggering conditions are met. However, in many cases, soil moisture is a predisposing factor that plays a major role in landslide initiation. Therefore, accounting for soil moisture conditions could improve the performance of LEWS.</p><p>Here we present the preliminary results defining hydrometeorological thresholds for the region of Catalonia (NE Spain). Such thresholds have been derived combining rainfall information from ground-based radar observations and the volumetric water content simulated by the LISFLOOD hydrological model. The information of recent and historical landslide events contained in a landslide inventory has been used to adjust the hydrometeorological thresholds.</p><p>The new hydrometeorological thresholds have been implemented into the regional-scale LEWS for the region of Catalonia.  Finally, the performance of the two versions of the LEWS (i.e. solely based on rainfall observations and adding soil moisture conditions) has been analysed for a recent rainfall event that triggered multiple landslides.</p>
This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time perform... more This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time performance over the region of Catalonia (NE Spain). The system uses high-resolution rainfall information obtained from weather radar observations and susceptibility maps to issue a qualitative warning level at a regional scale. To study the influence of the mapping unit on the LEWS outputs, susceptibility maps obtained for Catalonia based on (i) pixels of different sizes and (ii) hydrological subbasins have been compared. The susceptibility has been derived using a simple fuzzy logic approach combining slope angle and land cover data. The susceptibility maps for the different mapping units have then been employed to run the LEWS for a period of 7 months (warm season of 2010). For each configuration, the performance, interpretability of the warnings and, computational requirements have been compared to assess the suitability of each mapping unit for their use in the LEWS in real time. The configuration using pixels of 30 m resolution as mapping units seems to be the best as a compromise between resolution, performance and computational cost. However, from an end-user's real-time perspective the interpretation of the warnings can be difficult. Therefore, summarizing and visualizing the warnings, which are computed over the highresolution grid, by subbasins is proposed as the best option.
The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple l... more The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple landslides, some of which affected buildings and infrastructures (such as roads and railways). This paper presents the rainfall and landslide datasets collected during the event, and evaluates the performance of a regional landslide early warning system (LEWS) during the Gloria storm applying a fuzzy verification method. The majority of the inventoried landslides can be classified as slides, involving a limited volume of sediment (up to 10 m 3), and were triggered in cut slopes along linear infrastructures. Rainfall accumulations were significant in the whole region, especially in the Montseny area, where over 450 mm were registered in 96 h. Generally, the LEWS computed moderate and high warnings in the areas where large rainfall amounts were recorded, and showed good correspondence with the locations where landslides were reported. The fuzzy verification method has been applied using neighbouring windows of different sizes to obtain scale-dependant information on the LEWS performance. The skill of the LEWS considerably improves when enlarging the neighbouring window size from 500 m to 1 km.
Soil moisture plays a vital role in slope stability. As water infiltrates into the soil, shear st... more Soil moisture plays a vital role in slope stability. As water infiltrates into the soil, shear strength decreases eventually leading to failure. However, most of the existing regional-scale landslide early warning systems (LEWS) rely solely on rainfall information and use rainfall thresholds to determine if the landslide triggering conditions are met. The original version of the Catalonia region LEWS combines real-time rainfall observations and susceptibility to compute warnings. The LEWS applies a set of rainfall intensity-duration thresholds to determine if the rainfall conditions have the potential to trigger a landslide. This work explores the potential of using modelled soil moisture data in the Catalonia region LEWS. Volumetric water content (VWC) from the LISFLOOD hydrological simulations of the European Flood Awareness System and rainfall estimates have been analysed at the location of recent landslide events. Based on this data, a set of empirical hydrometeorological thresh...
<p>Risk mitigation for shallow slides and debris flows at a regional scale ... more <p>Risk mitigation for shallow slides and debris flows at a regional scale is a challenge. Landslide early warning systems (LEWS) are a helpful tool to anticipate the time and location of possible landslide events so that the authorities in charge of managing the landslide risk can plan their actions.</p><p>Traditionally, regional LEWS rely on rainfall information to asses if the landslide triggering conditions are met. However, in many cases, soil moisture is a predisposing factor that plays a major role in landslide initiation. Therefore, accounting for soil moisture conditions could improve the performance of LEWS.</p><p>Here we present the preliminary results defining hydrometeorological thresholds for the region of Catalonia (NE Spain). Such thresholds have been derived combining rainfall information from ground-based radar observations and the volumetric water content simulated by the LISFLOOD hydrological model. The information of recent and historical landslide events contained in a landslide inventory has been used to adjust the hydrometeorological thresholds.</p><p>The new hydrometeorological thresholds have been implemented into the regional-scale LEWS for the region of Catalonia.  Finally, the performance of the two versions of the LEWS (i.e. solely based on rainfall observations and adding soil moisture conditions) has been analysed for a recent rainfall event that triggered multiple landslides.</p>
Entre 2006 y 2015, el barranco de Portaine y su afluente, el barranco de Reguerals (comarca del P... more Entre 2006 y 2015, el barranco de Portaine y su afluente, el barranco de Reguerals (comarca del Pallars Sobira, Pirineos de Lleida), han presentado una intensa actividad torrencial. Durante este periodo se han producido diez avenidas, nueve de las cuales han provocado danos importantes en la carretera de acceso a las pistas de esqui de Port Aine e importantes perdidas economicas asociadas no solo a la reparacion de las infraestructuras, sino tambien a la interrupcion de la actividad turistica despues de cada episodio y a las inversiones realizadas para proteger la zona, como la instalacion de barreras dinamicas para la retencion de sedimentos. En este articulo se presenta una sintesis de los trabajos realizados desde dos opticas diferentes, el de la gestion del territorio, al ser la estacion de esqui uno de los motores socioeconomicos de la zona, y el cientifico, dado su interes para el estudio de la dinamica torrencial.
This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time perform... more This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time performance over the region of Catalonia (NE Spain). The system uses high-resolution rainfall information obtained from weather radar observations and susceptibility maps to issue a qualitative warning level at a regional scale. To study the influence of the mapping unit on the LEWS outputs, susceptibility maps obtained for Catalonia based on (i) pixels of different sizes and (ii) hydrological subbasins have been compared. The susceptibility has been derived using a simple fuzzy logic approach combining slope angle and land cover data. The susceptibility maps for the different mapping units have then been employed to run the LEWS for a period of 7 months (warm season of 2010). For each configuration, the performance, interpretability of the warnings and, computational requirements have been compared to assess the suitability of each mapping unit for their use in the LEWS in real time. The configuration using pixels of 30 m resolution as mapping units seems to be the best as a compromise between resolution, performance and computational cost. However, from an end-user's real-time perspective the interpretation of the warnings can be difficult. Therefore, summarizing and visualizing the warnings, which are computed over the highresolution grid, by subbasins is proposed as the best option.
The sensitive mountain catchment of Portainé (Eastern Pyrenees, Iberian Peninsula) has recently e... more The sensitive mountain catchment of Portainé (Eastern Pyrenees, Iberian Peninsula) has recently experienced a significant change in its torrential dynamics due to human disturbances. The emplacement of a ski resort at the headwaters led to the surpassing of a geomorphological threshold, with important consequences during flood events. Consequently, since 2008, channel dynamics have turned into sediment-laden, highly destructive torrential flows. In order to assess this phenomenon and o acquire a holistic understanding of the catchment’s behaviour, we carried out a field work-based multidisciplinary study. We considered the interaction of the various controlling factors, including bedrock geology, geomorphological evolution, derived soils and coluvial deposits, rainfall patterns, and the hydrological response of the catchment to flood events. Moreover, anthropogenic land-use changes, its consequential hydrogeomorphic effects and the role of vegetation were also taken into account. Ro...
Debris flow represents an important hazard in mountainous areas. During the night of the 21 st of... more Debris flow represents an important hazard in mountainous areas. During the night of the 21 st of August of 2015, a debris flow took place in one of the presently most active ravines of the Pyrenees, the Portainé torrent (Eastern Pyrenees, Spain) and caused considerable damage to the road. Detailed information was gathered from the debris flow monitoring system recently installed in the torrent and field surveys. The monitoring system measures ground vibration at geophones and flow height at an ultrasonic sensor. Meteorological data showed that the debris flow was triggered by a convective rainstorm with a total rainfall amount of 29 mm. All these data provide information on the debris flow occurrence and dynamics. The analysis of the data showed that the debris flow had three different surges and mobilized a total volume of about 2130 m 3. The front velocity in the monitoring reach was somewhat small (about 2 m/s) and the peak flow discharge comparatively low (about 13 m 3 /s). In addition, the debris flow was back-analysed by a numerical model calibrated by the observed event. The results of the simulation showed that a Voellmy fluid rheological model can represent considerably well the recorded and observed measurements and the best-fit values were µ = 0.28 and C = 8 m 0.5 /s.
The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple l... more The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple landslides, some of which affected buildings and infrastructures (such as roads and railways). This paper presents the rainfall and landslide datasets collected during the event, and evaluates the performance of a regional landslide early warning system (LEWS) during the Gloria storm applying a fuzzy verification method. The majority of the inventoried landslides can be classified as slides, involving a limited volume of sediment (up to 10 m3), and were triggered in cut slopes along linear infrastructures. Rainfall accumulations were significant in the whole region, especially in the Montseny area, where over 450 mm were registered in 96 h. Generally, the LEWS computed moderate and high warnings in the areas where large rainfall amounts were recorded, and showed good correspondence with the locations where landslides were reported. The fuzzy verification method has been applied using neig...
Risk mitigation for debris flows at regional scale is a challenge. Early warning systems are help... more Risk mitigation for debris flows at regional scale is a challenge. Early warning systems are helpful in depicting the time and the location of future debris flows so that emergency responders can act in advance before the disaster takes place. Herein we present a prototype real-time regional early warning system for rainfall induced shallow landslides and debris flows for the region of Catalonia (northeastern Spain). The model issues a warning level combining susceptibility information and real-time rainfall triggering conditions obtained from weather radar observations and forecasts. Susceptibility maps have been derived using a fuzzylogic approach and two input variables, terrain slope and land cover. These maps have been obtained using (i) grid cells of different resolutions, and (ii) physical catchments (of first order) as terrain units. Although high resolution grid-cell maps show a more accurate representation of susceptibility over the region, maps based on catchments are more intuitive and better characterize the area affected by future debris flows. Rainfall triggering conditions are assessed by means of probabilistic intensity-duration thresholds obtained from literature. Finally, we have validated the early warning system and tested its performance for some important events from the last ten years that were either monitored in specific catchments, or were reported in unmonitored catchments. In general, the system has been able to satisfactorily forecast the time of occurrence of most of the analyzed past debrisflow events.
<p>Risk mitigation for shallow slides and debris flows at a regional scale ... more <p>Risk mitigation for shallow slides and debris flows at a regional scale is a challenge. Landslide early warning systems (LEWS) are a helpful tool to anticipate the time and location of possible landslide events so that the authorities in charge of managing the landslide risk can plan their actions.</p><p>Traditionally, regional LEWS rely on rainfall information to asses if the landslide triggering conditions are met. However, in many cases, soil moisture is a predisposing factor that plays a major role in landslide initiation. Therefore, accounting for soil moisture conditions could improve the performance of LEWS.</p><p>Here we present the preliminary results defining hydrometeorological thresholds for the region of Catalonia (NE Spain). Such thresholds have been derived combining rainfall information from ground-based radar observations and the volumetric water content simulated by the LISFLOOD hydrological model. The information of recent and historical landslide events contained in a landslide inventory has been used to adjust the hydrometeorological thresholds.</p><p>The new hydrometeorological thresholds have been implemented into the regional-scale LEWS for the region of Catalonia.  Finally, the performance of the two versions of the LEWS (i.e. solely based on rainfall observations and adding soil moisture conditions) has been analysed for a recent rainfall event that triggered multiple landslides.</p>
This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time perform... more This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time performance over the region of Catalonia (NE Spain). The system uses high-resolution rainfall information obtained from weather radar observations and susceptibility maps to issue a qualitative warning level at a regional scale. To study the influence of the mapping unit on the LEWS outputs, susceptibility maps obtained for Catalonia based on (i) pixels of different sizes and (ii) hydrological subbasins have been compared. The susceptibility has been derived using a simple fuzzy logic approach combining slope angle and land cover data. The susceptibility maps for the different mapping units have then been employed to run the LEWS for a period of 7 months (warm season of 2010). For each configuration, the performance, interpretability of the warnings and, computational requirements have been compared to assess the suitability of each mapping unit for their use in the LEWS in real time. The configuration using pixels of 30 m resolution as mapping units seems to be the best as a compromise between resolution, performance and computational cost. However, from an end-user's real-time perspective the interpretation of the warnings can be difficult. Therefore, summarizing and visualizing the warnings, which are computed over the highresolution grid, by subbasins is proposed as the best option.
The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple l... more The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple landslides, some of which affected buildings and infrastructures (such as roads and railways). This paper presents the rainfall and landslide datasets collected during the event, and evaluates the performance of a regional landslide early warning system (LEWS) during the Gloria storm applying a fuzzy verification method. The majority of the inventoried landslides can be classified as slides, involving a limited volume of sediment (up to 10 m 3), and were triggered in cut slopes along linear infrastructures. Rainfall accumulations were significant in the whole region, especially in the Montseny area, where over 450 mm were registered in 96 h. Generally, the LEWS computed moderate and high warnings in the areas where large rainfall amounts were recorded, and showed good correspondence with the locations where landslides were reported. The fuzzy verification method has been applied using neighbouring windows of different sizes to obtain scale-dependant information on the LEWS performance. The skill of the LEWS considerably improves when enlarging the neighbouring window size from 500 m to 1 km.
Soil moisture plays a vital role in slope stability. As water infiltrates into the soil, shear st... more Soil moisture plays a vital role in slope stability. As water infiltrates into the soil, shear strength decreases eventually leading to failure. However, most of the existing regional-scale landslide early warning systems (LEWS) rely solely on rainfall information and use rainfall thresholds to determine if the landslide triggering conditions are met. The original version of the Catalonia region LEWS combines real-time rainfall observations and susceptibility to compute warnings. The LEWS applies a set of rainfall intensity-duration thresholds to determine if the rainfall conditions have the potential to trigger a landslide. This work explores the potential of using modelled soil moisture data in the Catalonia region LEWS. Volumetric water content (VWC) from the LISFLOOD hydrological simulations of the European Flood Awareness System and rainfall estimates have been analysed at the location of recent landslide events. Based on this data, a set of empirical hydrometeorological thresh...
<p>Risk mitigation for shallow slides and debris flows at a regional scale ... more <p>Risk mitigation for shallow slides and debris flows at a regional scale is a challenge. Landslide early warning systems (LEWS) are a helpful tool to anticipate the time and location of possible landslide events so that the authorities in charge of managing the landslide risk can plan their actions.</p><p>Traditionally, regional LEWS rely on rainfall information to asses if the landslide triggering conditions are met. However, in many cases, soil moisture is a predisposing factor that plays a major role in landslide initiation. Therefore, accounting for soil moisture conditions could improve the performance of LEWS.</p><p>Here we present the preliminary results defining hydrometeorological thresholds for the region of Catalonia (NE Spain). Such thresholds have been derived combining rainfall information from ground-based radar observations and the volumetric water content simulated by the LISFLOOD hydrological model. The information of recent and historical landslide events contained in a landslide inventory has been used to adjust the hydrometeorological thresholds.</p><p>The new hydrometeorological thresholds have been implemented into the regional-scale LEWS for the region of Catalonia.  Finally, the performance of the two versions of the LEWS (i.e. solely based on rainfall observations and adding soil moisture conditions) has been analysed for a recent rainfall event that triggered multiple landslides.</p>
Entre 2006 y 2015, el barranco de Portaine y su afluente, el barranco de Reguerals (comarca del P... more Entre 2006 y 2015, el barranco de Portaine y su afluente, el barranco de Reguerals (comarca del Pallars Sobira, Pirineos de Lleida), han presentado una intensa actividad torrencial. Durante este periodo se han producido diez avenidas, nueve de las cuales han provocado danos importantes en la carretera de acceso a las pistas de esqui de Port Aine e importantes perdidas economicas asociadas no solo a la reparacion de las infraestructuras, sino tambien a la interrupcion de la actividad turistica despues de cada episodio y a las inversiones realizadas para proteger la zona, como la instalacion de barreras dinamicas para la retencion de sedimentos. En este articulo se presenta una sintesis de los trabajos realizados desde dos opticas diferentes, el de la gestion del territorio, al ser la estacion de esqui uno de los motores socioeconomicos de la zona, y el cientifico, dado su interes para el estudio de la dinamica torrencial.
This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time perform... more This work presents a prototype Landslide Early Warning System (LEWS) adapted to real-time performance over the region of Catalonia (NE Spain). The system uses high-resolution rainfall information obtained from weather radar observations and susceptibility maps to issue a qualitative warning level at a regional scale. To study the influence of the mapping unit on the LEWS outputs, susceptibility maps obtained for Catalonia based on (i) pixels of different sizes and (ii) hydrological subbasins have been compared. The susceptibility has been derived using a simple fuzzy logic approach combining slope angle and land cover data. The susceptibility maps for the different mapping units have then been employed to run the LEWS for a period of 7 months (warm season of 2010). For each configuration, the performance, interpretability of the warnings and, computational requirements have been compared to assess the suitability of each mapping unit for their use in the LEWS in real time. The configuration using pixels of 30 m resolution as mapping units seems to be the best as a compromise between resolution, performance and computational cost. However, from an end-user's real-time perspective the interpretation of the warnings can be difficult. Therefore, summarizing and visualizing the warnings, which are computed over the highresolution grid, by subbasins is proposed as the best option.
The sensitive mountain catchment of Portainé (Eastern Pyrenees, Iberian Peninsula) has recently e... more The sensitive mountain catchment of Portainé (Eastern Pyrenees, Iberian Peninsula) has recently experienced a significant change in its torrential dynamics due to human disturbances. The emplacement of a ski resort at the headwaters led to the surpassing of a geomorphological threshold, with important consequences during flood events. Consequently, since 2008, channel dynamics have turned into sediment-laden, highly destructive torrential flows. In order to assess this phenomenon and o acquire a holistic understanding of the catchment’s behaviour, we carried out a field work-based multidisciplinary study. We considered the interaction of the various controlling factors, including bedrock geology, geomorphological evolution, derived soils and coluvial deposits, rainfall patterns, and the hydrological response of the catchment to flood events. Moreover, anthropogenic land-use changes, its consequential hydrogeomorphic effects and the role of vegetation were also taken into account. Ro...
Debris flow represents an important hazard in mountainous areas. During the night of the 21 st of... more Debris flow represents an important hazard in mountainous areas. During the night of the 21 st of August of 2015, a debris flow took place in one of the presently most active ravines of the Pyrenees, the Portainé torrent (Eastern Pyrenees, Spain) and caused considerable damage to the road. Detailed information was gathered from the debris flow monitoring system recently installed in the torrent and field surveys. The monitoring system measures ground vibration at geophones and flow height at an ultrasonic sensor. Meteorological data showed that the debris flow was triggered by a convective rainstorm with a total rainfall amount of 29 mm. All these data provide information on the debris flow occurrence and dynamics. The analysis of the data showed that the debris flow had three different surges and mobilized a total volume of about 2130 m 3. The front velocity in the monitoring reach was somewhat small (about 2 m/s) and the peak flow discharge comparatively low (about 13 m 3 /s). In addition, the debris flow was back-analysed by a numerical model calibrated by the observed event. The results of the simulation showed that a Voellmy fluid rheological model can represent considerably well the recorded and observed measurements and the best-fit values were µ = 0.28 and C = 8 m 0.5 /s.
The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple l... more The Gloria storm rainfalls affected Catalonia from 20 to 23 January 2020 and triggered multiple landslides, some of which affected buildings and infrastructures (such as roads and railways). This paper presents the rainfall and landslide datasets collected during the event, and evaluates the performance of a regional landslide early warning system (LEWS) during the Gloria storm applying a fuzzy verification method. The majority of the inventoried landslides can be classified as slides, involving a limited volume of sediment (up to 10 m3), and were triggered in cut slopes along linear infrastructures. Rainfall accumulations were significant in the whole region, especially in the Montseny area, where over 450 mm were registered in 96 h. Generally, the LEWS computed moderate and high warnings in the areas where large rainfall amounts were recorded, and showed good correspondence with the locations where landslides were reported. The fuzzy verification method has been applied using neig...
Risk mitigation for debris flows at regional scale is a challenge. Early warning systems are help... more Risk mitigation for debris flows at regional scale is a challenge. Early warning systems are helpful in depicting the time and the location of future debris flows so that emergency responders can act in advance before the disaster takes place. Herein we present a prototype real-time regional early warning system for rainfall induced shallow landslides and debris flows for the region of Catalonia (northeastern Spain). The model issues a warning level combining susceptibility information and real-time rainfall triggering conditions obtained from weather radar observations and forecasts. Susceptibility maps have been derived using a fuzzylogic approach and two input variables, terrain slope and land cover. These maps have been obtained using (i) grid cells of different resolutions, and (ii) physical catchments (of first order) as terrain units. Although high resolution grid-cell maps show a more accurate representation of susceptibility over the region, maps based on catchments are more intuitive and better characterize the area affected by future debris flows. Rainfall triggering conditions are assessed by means of probabilistic intensity-duration thresholds obtained from literature. Finally, we have validated the early warning system and tested its performance for some important events from the last ten years that were either monitored in specific catchments, or were reported in unmonitored catchments. In general, the system has been able to satisfactorily forecast the time of occurrence of most of the analyzed past debrisflow events.
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