Relationship of runoff, erosion and sediment yield to weather types in the Iberian Peninsula

Precipitation has been recognized as one of the main factors driving soil erosion and sediment yield (SY), and its spatial and temporal variability is recognized as one of themain reasons for spatial and temporal analyses of soil erosion variability. The weather types (WTs) approach classifies the continuumof atmospheric circulation into a small number of categories or types and has been proven a good indicator of the spatial and temporal variability of precipitation. Thus, themain objective of this study is to analyze the relationship betweenWTs, runoff, soil erosion (measured in plots), and sediment yield (measured in catchments) in different areas of the Iberian Peninsula (IP) with the aimof detecting spatial variations in these relationships. To this end, hydrological and sediment information covering the IP from several Spanish research teams has been combined, and related with daily WTs estimated by using the NMC/NCAR 40-Year Reanalysis Project. The results showthat, in general, a fewWTs (particularly westerly, southwesterly and cyclonic) provide the largest amounts of precipitation; and southwesterly, northwesterly and westerly WTs play an important role in runoff generation, erosion and sediment yield as they coincide with the wettest WTs. However, this study highlights the spatial variability of erosion and sediment yield in the IP according to WT, differentiating (1) areas under the influence of north and/or north-westerly flows (the north coast of Cantabria and inland central areas), (2) areas under the influence of westerly, southwesterly and cyclonic WTs (western and southwestern IP), (3) areas in which erosion and sediment yield are controlled by easterly flows (Mediterranean coastland), and (4) lastly, a transitional zone in the inland northeast Ebro catchment,wherewe detected a high variability in the effects ofWTs on erosion. Overall results suggest that the use of WTs derived fromobserved atmospheric pressure patterns could be a useful tool for inclusion in future projections of the spatial variability of erosion and sediment yield, as models capture pressure fields reliably

Determining gully volume from straightforward photo-based 3D reconstruction

Geophysical Research Abstracts, Vol. 14, EGU2012-4597, 2012 In order to quantify soil loss through gully erosion, accurate measurements of gully volume are required. However, gullys are usually extended features, often with complex morphologies and are challenging to survey appropriately and efficiently. Here we explore the use of a photo-based technique for deriving 3D gully models suitable for detailed erosion studies. Traditional aerial and oblique close-range photogrammetry approaches have been previously used to produce accurate digital elevation models (DEMs) from photographs. However, these techniques require expertise to carry out successfully, use proprietry software and usually need apriori camera calibration. The computer vision approach we adopt here relaxes these requirements and allows 3D models to be automatically produced from collections of unordered photos. We use a freely available ‘reconstruction pipeline’ (http://blog.neonascent.net/archives/bundler-photogrammetry-package/) that combines structure-from-motion and multi-view stereo algorithms (SfM-MVS) to generate dense point clouds (millions of points). The model is derived from photos taken from different positions with a consumer camera and is then scaled and georeferenced using additional software (http://www.lancs.ac.uk/ staff/jamesm/software/sfm_georef.htm) and observations of some control points in the scene. The approach was tested on a ~7-m long sinous gully section (average width and depth ~2.4 and 1.2 m respectively) in Vertisol soils, near Cordoba, Spain. For benchmark data, the gully topography was determined with a terrestrial laser scanner (Riegl LMS-Z420i, with a cited range accuracy of 10 mm). 191 photos were taken with a Canon EOS 450D with a prime (fixed) 28 mm lens over a period of ~10 minutes. In order to georeference the SfM-MVS model for comparison with the TLS data, 6 control targets were located around the gully and their locations determined by dGPS. Differences between the TLS and SfM-MVS surfaces are dominated by areas of data gaps from either one of the techniques with some additional issues related to small amounts of vegetation on steep gully walls. The overall difference between the surfaces represents <2 % of the gully volume surveyed. This supports the viability of SfM-MVS as a useful tool for gully evaluations, capable of producing accurate DEMs at low cost

Comparing the accuracy of several field methods for measuring gully erosion

Most fi eld erosion studies in agricultural areas provide little information on the probable errors involved. Here, for the fi rst time, we compare the accuracy, time and cost of conventional and new methodologies for gully surveying, and provide a model to estimate the effort required to achieve a specifi ed accuracy. Using a terrestrial LiDAR survey of a 7.1-m-long gully reach as a benchmark data set, the accuracies of different measurement methods (a new 3D photo-reconstruction technique, total station, laser profi lemeter, and pole) are assessed for estimating gully erosion at a reach scale. Based on further fi eld measurements performed over nine gullies (>100 m long), a simulation approach is derived to model the expected volume errors when 2D methods are used at the gully scale. All gullies considered were located near Cordoba, Spain. At the reach scale, the fi eld measurements using 3D photo-reconstruction and total station techniques produced cross-sectional area error values smaller than 4%, with other 2D methods exceeding 10%. For volume estimation, photo-reconstruction proved similar to LiDAR data, but 2D methods generated large negative volume error (EV) values (<–13% for laser profi lemeter and pole). We show that the proposed error expressions derived from the model are in line with the reach-scale fi eld results. A measurement distance factor (MDF) is defi ned that represents the ratio between cross-section distance and the gully length, and thus refl ects relative survey effort. We calculate the required MDF for specifi ed values of EV, illustrating how MDF decreases with increasing gully length and sinuosity

The normalized topographic method:an automated procedure for gully mapping using GIS

Gully delineation is a critical aspect of accurately determining soil losses but associated methodologies are rarely detailed. Here, we describe a new gully mapping method, the normalized topographic method (NorToM), based on processing digital elevation model (DEM) data, and we assess associated errors when it is applied over a range of geomorphological scales. The NorToM is underpinned by two gully detection variables (normalized slope and elevation) calculated over local windows of prescribed size, and a group of filtering variables. For four study sites, DEMs of gullies were obtained using field and airborne photo-reconstruction and evaluated using total station and differential global positioning system (dGPS) survey. NorToM provided accurate areal and volume estimates at the individual gully scale but differences increased at the larger gully system and gully network scales. We were able to identify optimal parameters for using the NorToM approach and so confirm that is represents a useful scale-independent means of gully mapping that is likely to be valid in other environments. Its main limitations are that the normalization process might be time-consuming at regional scales and the need for a fixed window size when applied to landforms with extreme variations in dimensions

Introduction to the special issue on soil hydrology: part 2

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El uso de mundos virtuales inmersivos en la mejora transversal de competencias de trabajo en equipo, creatividad e innovación

The Teaching Innovation Plan 2015-2016 of the University of Cordoba had among its priorities competency-based work (line 1), the promotion of virtual teaching (line 10) and tutoring students (line 12). In this context, the use of immersive virtual worlds has been applied to improve teamwork competencies and the management of virtual tools, both being important and transferable aspects to the learning of any discipline. Thus, an immersive virtual scenario was created to enable work meetings, and group activities were designed for learning the handling of avatars in working groups. In addition, tutored activities aimed at solving group doubts as well as definitely improving creativity in an innovative and different atmosphere. These sessions were included within the practices of the subject "Projects" of the degree of Agri-food Engineering and Rural Environment. The results of the evaluation of the experience -as an ad hoc survey designed to characterize the learning curve of the management of avatars and immersive worlds-, showed the success and usefulness of the project whose material is reusable in future educational experiences.El Plan de Innovación Docente 2015-2016 de la Universidad de Córdoba tenía entre sus líneas prioritarias tanto el trabajo en competencias (línea 1), como el fomento de la enseñanza virtual (línea 10) y la tutorización del alumnado (línea 12). En este contexto, nuestro trabajo ha aplicado y evaluado el uso de mundos virtuales inmersivos para la mejora del manejo de herramientas virtuales y competencias de trabajo en equipo, aspectos claves y transferibles al aprendizaje de cualquier disciplina. Así, se creó un escenario virtual inmersivo para reuniones de trabajo y se diseñaron unas actividades grupales que incluían un manual para el aprendizaje del manejo de avatares y su interacción en un grupo de trabajo en mundos inmersivos. Además se llevaron a cabo actividades tutoradas dirigidas a resolver dudas en grupo así como para definitivamente mejorar la creatividad en un contexto innovador y diferente. Estas sesiones se incluyeron dentro de las prácticas de la asignatura “Proyectos” del grado de Ingeniería Agroalimentaria y del Medio Rural. Los resultados de la evaluación de la experiencia a modo de encuestas diseñadas ad hoc para caracterizar la curva de aprendizaje del manejo de avatares y mundos inmersivos, puso de manifiesto el éxito y utilidad del proyecto cuyo material es reutilizable en futuras experiencias educativas

Modelling Runoff and Sediment Loads in a Developing Coastal Watershed of the US-Mexico Border

Urbanization can increase sheet, rill, gully, and channel erosion. We quantified the sediment budget of the Los Laureles Canyon watershed (LLCW), which is a mixed rural-urbanizing catchment in Northwestern Mexico, using the AnnAGNPS model and field measurements of channel geometry. The model was calibrated with five years of observed runoff and sediment loads and used to evaluate sediment reduction under a mitigation scenario involving paving roads in hotspots of erosion. Calibrated runoff and sediment load had a mean-percent-bias of 28.4 and &#8722; 8.1, and root-mean-square errors of 85% and 41% of the mean, respectively. Suspended sediment concentration (SSC) collected at different locations during one storm-event correlated with modeled SSC at those locations, which suggests that the model represented spatial variation in sediment production. Simulated gully erosion represents 16%&#8211;37% of hillslope sediment production, and 50% of the hillslope sediment load is produced by only 23% of the watershed area. The model identifies priority locations for sediment control measures, and can be used to identify tradeoffs between sediment control and runoff production. Paving roads in priority areas would reduce total sediment yield by 30%, but may increase peak discharge moderately (1.6%&#8211;21%) at the outlet

Gamification for the Acquisition of Leadership Skills and Formation of Efficient Work Teams: An Interactive Workshop Based on an Analysis of the Film “The Seven Samurai”

In this work, we present a teaching experience based on emerging pedagogies and gamification to improve leadership skills and achieve efficient teamwork in scientific-technical areas of Engineering Projects. We designed the contents of a workshop and a virtual tool to create emotional contexts that improved the acquisition of soft skills. The combination of multi-sensory pedagogical strategies and hybrid inductive-deductive methodologies based on tests and team games, inspired by the story line of the classic film "The Seven Samurai" (Kurosawa, 1954), allowed us both to carry out, over a period of two academic years, an “on-the-ground” workshop-game, and a virtual tool to interact in the workshop, while under the COVID-19 restrictions.&nbsp; Despite the different formats and gamification elements used over the two academic years, the metrics for evaluating the efficiency of acquiring these soft skills produced very positive results and, on the whole, did not show significant differences. The cinematographic language and empathy with the story and the characters led the students to identify with and internalize the elements of efficient teamwork and leadership. Movies can provide simple but effective narrative lines on which to build games. Here, we present the contents and details of both workshops as a transferable experience, as well as making the open virtual tool available for the educative community

Relationship of runoff, erosion and sediment yield to weather types in the Iberian Peninsula

Precipitation has been recognized as one of the main factors driving soil erosion and sediment yield (SY), and its spatial and temporal variability is recognized as one of themain reasons for spatial and temporal analyses of soil erosion variability. The weather types (WTs) approach classifies the continuumof atmospheric circulation into a small number of categories or types and has been proven a good indicator of the spatial and temporal variability of precipitation. Thus, themain objective of this study is to analyze the relationship betweenWTs, runoff, soil erosion (measured in plots), and sediment yield (measured in catchments) in different areas of the Iberian Peninsula (IP) with the aimof detecting spatial variations in these relationships. To this end, hydrological and sediment information covering the IP from several Spanish research teams has been combined, and related with daily WTs estimated by using the NMC/NCAR 40-Year Reanalysis Project. The results showthat, in general, a fewWTs (particularly westerly, southwesterly and cyclonic) provide the largest amounts of precipitation; and southwesterly, northwesterly and westerly WTs play an important role in runoff generation, erosion and sediment yield as they coincide with the wettest WTs. However, this study highlights the spatial variability of erosion and sediment yield in the IP according to WT, differentiating (1) areas under the influence of north and/or north-westerly flows (the north coast of Cantabria and inland central areas), (2) areas under the influence of westerly, southwesterly and cyclonic WTs (western and southwestern IP), (3) areas in which erosion and sediment yield are controlled by easterly flows (Mediterranean coastland), and (4) lastly, a transitional zone in the inland northeast Ebro catchment,wherewe detected a high variability in the effects ofWTs on erosion. Overall results suggest that the use of WTs derived fromobserved atmospheric pressure patterns could be a useful tool for inclusion in future projections of the spatial variability of erosion and sediment yield, as models capture pressure fields reliably