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Watering ponds represent an important part of the hydrological resources in some water-limited environments. Knowledge about their storage capacity and geometrical characteristics is crucial for a better understanding and management of water resources in the context of climate change. In this study, the suitability of different geomatic approaches to model watering pond geometry and estimate pond-specific and generalized volume–area–height (V–A–h) relationships was tested. Terrestrial structure-from-motion and multi-view-stereo photogrammetry (SfM-MVS), terrestrial laser scanner (TLS), laser-imaging detection and ranging (LIDAR), and aerial SfM-MVS were tested for the emerged terrain, while the global navigation satellite system (GNSS) was used to survey the submerged terrain and to test the resulting digital elevation models (DEMs). The combined use of terrestrial SfM-MVS and GNSS produced accurate DEMs of the ponds that resulted in an average error of 1.19% in the maximum volume estimation, comparable to that obtained by the TLS+GNSS approach (3.27%). From these DEMs, power and quadratic functions were used to express pond-specific and generalized V–A–h relationships and checked for accuracy. The results revealed that quadratic functions fit the data particularly well (R2 ≥ 0.995 and NRMSE < 2.25%) and can therefore be reliably used as simple geometric models of watering ponds in hydrological simulation studies. Finally, a generalized V–A power relationship was obtained. This relationship may be a valuable tool to estimate the storage capacity of other watering ponds in comparable areas in a context of data scarcity.
Ubaldo Marín-Comitre; Álvaro Gómez-Gutiérrez; Francisco Lavado-Contador; Manuel Sánchez-Fernández; Alberto Alfonso-Torreño. Using Geomatic Techniques to Estimate Volume–Area Relationships of Watering Ponds. ISPRS International Journal of Geo-Information 2021, 10, 502 .
AMA StyleUbaldo Marín-Comitre, Álvaro Gómez-Gutiérrez, Francisco Lavado-Contador, Manuel Sánchez-Fernández, Alberto Alfonso-Torreño. Using Geomatic Techniques to Estimate Volume–Area Relationships of Watering Ponds. ISPRS International Journal of Geo-Information. 2021; 10 (8):502.
Chicago/Turabian StyleUbaldo Marín-Comitre; Álvaro Gómez-Gutiérrez; Francisco Lavado-Contador; Manuel Sánchez-Fernández; Alberto Alfonso-Torreño. 2021. "Using Geomatic Techniques to Estimate Volume–Area Relationships of Watering Ponds." ISPRS International Journal of Geo-Information 10, no. 8: 502.
Monitoring the dynamics of coastal cliffs is fundamental for the safety of communities, buildings, utilities, and infrastructures located near the coastline. Structure-from-Motion and Multi View Stereo (SfM-MVS) photogrammetry based on Unmanned Aerial Systems (UAS) is a flexible and cost-effective surveying technique for generating a dense 3D point cloud of the whole cliff face (from bottom to top), with high spatial and temporal resolution. In this paper, in order to generate a reproducible, reliable, precise, accurate, and dense point cloud of the cliff face, a comprehensive analysis of the SfM-MVS processing parameters, image redundancy and acquisition geometry was performed. Using two different UAS, a fixed-wing and a multi-rotor, two flight missions were executed with the aim of reconstructing the geometry of an almost vertical cliff located at the central Portuguese coast. The results indicated that optimizing the processing parameters of Agisoft Metashape can improve the 3D accuracy of the point cloud up to 2 cm. Regarding the image acquisition geometry, the high off-nadir (90°) dataset taken by the multi-rotor generated a denser and more accurate point cloud, with lesser data gaps, than that generated by the low off-nadir dataset (3°) taken by the fixed wing. Yet, it was found that reducing properly the high overlap of the image dataset acquired by the multi-rotor drone permits to get an optimal image dataset, allowing to speed up the processing time without compromising the accuracy and density of the generated point cloud. The analysis and results presented in this paper improve the knowledge required for the 3D reconstruction of coastal cliffs by UAS, providing new insights into the technical aspects needed for optimizing the monitoring surveys.
Gil Gonçalves; Diogo Gonçalves; Álvaro Gómez-Gutiérrez; Umberto Andriolo; Juan Pérez-Alvárez. 3D Reconstruction of Coastal Cliffs from Fixed-Wing and Multi-Rotor UAS: Impact of SfM-MVS Processing Parameters, Image Redundancy and Acquisition Geometry. Remote Sensing 2021, 13, 1222 .
AMA StyleGil Gonçalves, Diogo Gonçalves, Álvaro Gómez-Gutiérrez, Umberto Andriolo, Juan Pérez-Alvárez. 3D Reconstruction of Coastal Cliffs from Fixed-Wing and Multi-Rotor UAS: Impact of SfM-MVS Processing Parameters, Image Redundancy and Acquisition Geometry. Remote Sensing. 2021; 13 (6):1222.
Chicago/Turabian StyleGil Gonçalves; Diogo Gonçalves; Álvaro Gómez-Gutiérrez; Umberto Andriolo; Juan Pérez-Alvárez. 2021. "3D Reconstruction of Coastal Cliffs from Fixed-Wing and Multi-Rotor UAS: Impact of SfM-MVS Processing Parameters, Image Redundancy and Acquisition Geometry." Remote Sensing 13, no. 6: 1222.
Mega-gullies and landslides pose significant hazards to urban development on steep terrain. Water resources infrastructure failures (WRIFs), such as leaks and breaks in water supply pipes, have been postulated as a trigger of mass movement events but data for validation has been challenging to acquire since earthwork proceeds quickly after events to repair roads and other infrastructure. Urban development in Tijuana, Mexico was monitored for a five-year period to document the occurrence of mega-gullies and landslides, including sediment volumes. A rapid assessment approach was developed based on photogrammetric observations from an unmanned aerial vehicle (UAV) and Structure from Motion (SfM) digital processing. Three hazardous mass-movement events were observed including two mega-gullies and one landslide. Furthermore, all three events were linked to WRIFs. Frequency analysis points to the annual probability of a WRIF-based erosion event in the range of 40–60 %, which is far higher than design levels typically used for urban stormwater infrastructure (5–10 %). Additionally, sediment modelling points to WRIF-based erosion as a non-negligible contributor to sediment generation. These results suggest that WRIFs are a significant contributor to erosion hazards facing urban development on steep terrain, and call for expanded monitoring to characterize the occurrence and modes of WRIF-based erosion events.
Napoleon Gudino-Elizondo; Matthew W. Brand; Trent W. Biggs; Alvaro Gomez-Gutierrez; Eddy Langendoen; Ronald Bingner; Yongping Yuan; Brett F. Sanders. Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures. 2021, 2021, 1 -22.
AMA StyleNapoleon Gudino-Elizondo, Matthew W. Brand, Trent W. Biggs, Alvaro Gomez-Gutierrez, Eddy Langendoen, Ronald Bingner, Yongping Yuan, Brett F. Sanders. Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures. . 2021; 2021 ():1-22.
Chicago/Turabian StyleNapoleon Gudino-Elizondo; Matthew W. Brand; Trent W. Biggs; Alvaro Gomez-Gutierrez; Eddy Langendoen; Ronald Bingner; Yongping Yuan; Brett F. Sanders. 2021. "Rapid assessment of urban mega-gully and landslide events with Structure-from-Motion techniques validates link to water resources infrastructure failures." 2021, no. : 1-22.
Gullies are sources and reservoirs of sediments and perform as efficient transfers of runoff and sediments. In recent years, several techniques and technologies emerged to facilitate monitoring of gully dynamics at unprecedented spatial and temporal resolutions. Here we present a detailed study of a valley-bottom gully in a Mediterranean rangeland with a savannah-like vegetation cover that was partially restored in 2017. Restoration activities included check dams (gabion weirs and fascines) and livestock exclosure by fencing. The specific objectives of this work were: (1) to analyze the effectiveness of the restoration activities, (2) to study erosion and deposition dynamics before and after the restoration activities using high-resolution digital elevation models (DEMs), (3) to examine the role of micro-morphology on the observed topographic changes, and (4) to compare the current and recent channel dynamics with previous studies conducted in the same study area through different methods and spatio-temporal scales, quantifying medium-term changes. Topographic changes were estimated using multi-temporal, high-resolution DEMs produced using structure-from-motion (SfM) photogrammetry and aerial images acquired by a fixed-wing unmanned aerial vehicle (UAV). The performance of the restoration activities was satisfactory to control gully erosion. Check dams were effective favoring sediment deposition and reducing lateral bank erosion. Livestock exclosure promoted the stabilization of bank headcuts. The implemented restoration measures increased notably sediment deposition.
Alberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel. Dynamics of Erosion and Deposition in a Partially Restored Valley-Bottom Gully. Land 2021, 10, 62 .
AMA StyleAlberto Alfonso-Torreño, Álvaro Gómez-Gutiérrez, Susanne Schnabel. Dynamics of Erosion and Deposition in a Partially Restored Valley-Bottom Gully. Land. 2021; 10 (1):62.
Chicago/Turabian StyleAlberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel. 2021. "Dynamics of Erosion and Deposition in a Partially Restored Valley-Bottom Gully." Land 10, no. 1: 62.
Manuel Pulido Fernández; Ali Keshavarzi; Jesús Rodrigo-Comino; Susanne Schnabel; Joaquín Francisco Lavado Contador; Álvaro Gómez Gutiérrez; Francisco Javier Lozano Parra; Jesús Barrena González; Alberto Alfonso Torreño; Artemi Cerdà. Developing scoring functions to assess soil quality at a regional scale in rangelands of SW Spain. Revista Brasileira de Ciência do Solo 2020, 44, 1 .
AMA StyleManuel Pulido Fernández, Ali Keshavarzi, Jesús Rodrigo-Comino, Susanne Schnabel, Joaquín Francisco Lavado Contador, Álvaro Gómez Gutiérrez, Francisco Javier Lozano Parra, Jesús Barrena González, Alberto Alfonso Torreño, Artemi Cerdà. Developing scoring functions to assess soil quality at a regional scale in rangelands of SW Spain. Revista Brasileira de Ciência do Solo. 2020; 44 ():1.
Chicago/Turabian StyleManuel Pulido Fernández; Ali Keshavarzi; Jesús Rodrigo-Comino; Susanne Schnabel; Joaquín Francisco Lavado Contador; Álvaro Gómez Gutiérrez; Francisco Javier Lozano Parra; Jesús Barrena González; Alberto Alfonso Torreño; Artemi Cerdà. 2020. "Developing scoring functions to assess soil quality at a regional scale in rangelands of SW Spain." Revista Brasileira de Ciência do Solo 44, no. : 1.
Rainfall is the key factor to understand soil erosion processes, mechanisms, and rates. Most research was conducted to determine rainfall characteristics and their relationship with soil erosion (erosivity) but there is little information about how atmospheric patterns control soil losses, and this is important to enable sustainable environmental planning and risk prevention. We investigated the temporal and spatial variability of the relationships of rainfall, runoff, and sediment yield with atmospheric patterns (weather types, WTs) in the western Mediterranean basin. For this purpose, we analyzed a large database of rainfall events collected between 1985 and 2015 in 46 experimental plots and catchments with the aim to: (i) evaluate seasonal differences in the contribution of rainfall, runoff, and sediment yield produced by the WTs; and (ii) to analyze the seasonal efficiency of the different WTs (relation frequency and magnitude) related to rainfall, runoff, and sediment yield. The results indicate two different temporal patterns: the first weather type exhibits (during the cold period: autumn and winter) westerly flows that produce the highest rainfall, runoff, and sediment yield values throughout the territory; the second weather type exhibits easterly flows that predominate during the warm period (spring and summer) and it is located on the Mediterranean coast of the Iberian Peninsula. However, the cyclonic situations present high frequency throughout the whole year with a large influence extended around the western Mediterranean basin. Contrary, the anticyclonic situations, despite of its high frequency, do not contribute significantly to the total rainfall, runoff, and sediment (showing the lowest efficiency) because of atmospheric stability that currently characterize this atmospheric pattern. Our approach helps to better understand the relationship of WTs on the seasonal and spatial variability of rainfall, runoff and sediment yield with a regional scale based on the large dataset and number of soil erosion experimental stations.
D. Peña-Angulo; E. Nadal-Romero; J.C. González-Hidalgo; J. Albaladejo; V. Andreu; H. Bahri; S. Bernal; M. Biddoccu; R. Bienes; J. Campo; Miguel Ángel Campo-Bescós; A. Canatário-Duarte; Y. Cantón; J. Casali; V. Castillo; E. Cavallo; A. Cerdà; P. Cid; N. Cortesi; G. Desir; Elvira Diaz Pereira; T. Espigares; J. Estrany; J. Farguell; M. Fernández-Raga; C.S. Ferreira; V. Ferro; F. Gallart; R. Giménez; E. Gimeno; J.A. Gómez; A. Gómez-Gutiérrez; H. Gómez-Macpherson; O. González-Pelayo; O. Kairis; G.P. Karatzas; S. Keesstra; S. Klotz; C. Kosmas; N. Lana-Renault; T. Lasanta; J. Latron; R. Lázaro; Y. Le Bissonnais; C. Le Bouteiller; F. Licciardello; J.A. López-Tarazón; A. Lucía; V.M. Marín-Moreno; C. Marín; M.J. Marqués; J. Martínez-Fernández; M. Martínez-Mena; L. Mateos; N. Mathys; L. Merino-Martín; M. Moreno-De Las Heras; N. Moustakas; J.M. Nicolau; V. Pampalone; D. Raclot; M.L. Rodríguez-Blanco; J. Rodrigo-Comino; A. Romero-Díaz; Encarnación Taguas Ruiz; J.L. Rubio; S. Schnabel; J.M. Senciales-González; A. Solé-Benet; E.V. Taguas; M.T. Taboada-Castro; F. Todisco; X. Úbeda; E.A. Varouchakis; L. Wittenberg; A. Zabaleta; M. Zorn. Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin. Atmosphere 2020, 11, 609 .
AMA StyleD. Peña-Angulo, E. Nadal-Romero, J.C. González-Hidalgo, J. Albaladejo, V. Andreu, H. Bahri, S. Bernal, M. Biddoccu, R. Bienes, J. Campo, Miguel Ángel Campo-Bescós, A. Canatário-Duarte, Y. Cantón, J. Casali, V. Castillo, E. Cavallo, A. Cerdà, P. Cid, N. Cortesi, G. Desir, Elvira Diaz Pereira, T. Espigares, J. Estrany, J. Farguell, M. Fernández-Raga, C.S. Ferreira, V. Ferro, F. Gallart, R. Giménez, E. Gimeno, J.A. Gómez, A. Gómez-Gutiérrez, H. Gómez-Macpherson, O. González-Pelayo, O. Kairis, G.P. Karatzas, S. Keesstra, S. Klotz, C. Kosmas, N. Lana-Renault, T. Lasanta, J. Latron, R. Lázaro, Y. Le Bissonnais, C. Le Bouteiller, F. Licciardello, J.A. López-Tarazón, A. Lucía, V.M. Marín-Moreno, C. Marín, M.J. Marqués, J. Martínez-Fernández, M. Martínez-Mena, L. Mateos, N. Mathys, L. Merino-Martín, M. Moreno-De Las Heras, N. Moustakas, J.M. Nicolau, V. Pampalone, D. Raclot, M.L. Rodríguez-Blanco, J. Rodrigo-Comino, A. Romero-Díaz, Encarnación Taguas Ruiz, J.L. Rubio, S. Schnabel, J.M. Senciales-González, A. Solé-Benet, E.V. Taguas, M.T. Taboada-Castro, F. Todisco, X. Úbeda, E.A. Varouchakis, L. Wittenberg, A. Zabaleta, M. Zorn. Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin. Atmosphere. 2020; 11 (6):609.
Chicago/Turabian StyleD. Peña-Angulo; E. Nadal-Romero; J.C. González-Hidalgo; J. Albaladejo; V. Andreu; H. Bahri; S. Bernal; M. Biddoccu; R. Bienes; J. Campo; Miguel Ángel Campo-Bescós; A. Canatário-Duarte; Y. Cantón; J. Casali; V. Castillo; E. Cavallo; A. Cerdà; P. Cid; N. Cortesi; G. Desir; Elvira Diaz Pereira; T. Espigares; J. Estrany; J. Farguell; M. Fernández-Raga; C.S. Ferreira; V. Ferro; F. Gallart; R. Giménez; E. Gimeno; J.A. Gómez; A. Gómez-Gutiérrez; H. Gómez-Macpherson; O. González-Pelayo; O. Kairis; G.P. Karatzas; S. Keesstra; S. Klotz; C. Kosmas; N. Lana-Renault; T. Lasanta; J. Latron; R. Lázaro; Y. Le Bissonnais; C. Le Bouteiller; F. Licciardello; J.A. López-Tarazón; A. Lucía; V.M. Marín-Moreno; C. Marín; M.J. Marqués; J. Martínez-Fernández; M. Martínez-Mena; L. Mateos; N. Mathys; L. Merino-Martín; M. Moreno-De Las Heras; N. Moustakas; J.M. Nicolau; V. Pampalone; D. Raclot; M.L. Rodríguez-Blanco; J. Rodrigo-Comino; A. Romero-Díaz; Encarnación Taguas Ruiz; J.L. Rubio; S. Schnabel; J.M. Senciales-González; A. Solé-Benet; E.V. Taguas; M.T. Taboada-Castro; F. Todisco; X. Úbeda; E.A. Varouchakis; L. Wittenberg; A. Zabaleta; M. Zorn. 2020. "Relationship of Weather Types on the Seasonal and Spatial Variability of Rainfall, Runoff, and Sediment Yield in the Western Mediterranean Basin." Atmosphere 11, no. 6: 609.
Image network geometry, including the number and orientation of images, impacts the error, coverage, and processing time of 3‐D terrain mapping performed using Structure‐from‐Motion and MultiView‐Stereo (SfM‐MVS). Few studies have quantified tradeoffs in error and processing time or ways to optimize image acquisition in diverse topographic conditions. Here, we determine suitable camera locations for image acquisition by minimizing the occlusion produced by topography. Viewshed analysis is used to select the suitable images, which requires a preliminary Digital Elevation Model (DEM), potential camera locations and sensor parameters. One aerial and two ground‐based image collections were used to analyze differences between SfM‐MVS models produced using: 1) all available images (ALL), 2) images selected using conventional methods (CON); and 3) images selected using the viewshed analysis (VIEW). The resulting models were compared with benchmark point clouds acquired by a Terrestrial Laser Scanner (TLS) and TLS‐derived DEMs. The VIEW datasets produced denser point clouds (28‐32% more points) and DEMs with up to 66% reduction in error compared with CON datasets due to reduction of gaps in the DEM. VIEW datasets reduced processing time by 37‐76% compared with ALL, with no reduction in coverage or increase in error. DEMs produced with ALL and VIEW datasets had similar slope and roughness, while slight differences that may be locally important were observed for the CON dataset. The new method helps optimize SfM‐MVS image collection strategies that significantly reduce the number of images required with minimal loss in coverage or accuracy over complex surfaces.
Álvaro Gómez‐Gutiérrez; Trent Biggs; Napoleon Gudino Elizondoa; Paz Errea; Esteban Alonso González; Estela Nadal Romero; José Juan De Sanjosé Blasco. Using visibility analysis to improve point density and processing time of SfM‐MVS techniques for 3D reconstruction of landforms. Earth Surface Processes and Landforms 2020, 45, 2524 -2539.
AMA StyleÁlvaro Gómez‐Gutiérrez, Trent Biggs, Napoleon Gudino Elizondoa, Paz Errea, Esteban Alonso González, Estela Nadal Romero, José Juan De Sanjosé Blasco. Using visibility analysis to improve point density and processing time of SfM‐MVS techniques for 3D reconstruction of landforms. Earth Surface Processes and Landforms. 2020; 45 (11):2524-2539.
Chicago/Turabian StyleÁlvaro Gómez‐Gutiérrez; Trent Biggs; Napoleon Gudino Elizondoa; Paz Errea; Esteban Alonso González; Estela Nadal Romero; José Juan De Sanjosé Blasco. 2020. "Using visibility analysis to improve point density and processing time of SfM‐MVS techniques for 3D reconstruction of landforms." Earth Surface Processes and Landforms 45, no. 11: 2524-2539.
The increasing availability of highly detailed and accurate three-dimensional (3D) geospatial data are currently pushing the 3D change detection analysis towards a new 3D mapping frame. In this paper, medium-term changes (8 years) at a coastal rocky cliff are quantified using and comparing 2.5D and 3D methods to estimate the volume of rockfalls and three datasets: one Terrestrial Laser Scanner (TLS) acquired in 2010 and two coincident Unmanned Aerial Vehicles (UAV: multirotor and fixed-wing) datasets acquired in 2018. Advantages and limitations of these techniques, platforms and methods are discussed and the role of Ground Control Points (GCPs) distribution was analysed. Maps of 3D changes were produced by means of the Multiscale-Model-to-Model Cloud-Comparison algorithm (M3C2). The volume of the eroded-deposited material was estimated using two 2.5D and one 3D approaches: 1) rasterizing M3C2 distances using a conventional top-view perspective, 2) rasterizing the M3C2 distances rotated and orientated with the z vector normal and, 3) for the largest rockfalls, the volume was estimated using the Poisson Surface Reconstruction (PSR) algorithm (3D). The 3D models produced using both UAV platforms showed cm-level accuracies with Root Mean Square Error (RMSE) of 0.02 and 0.03 m for the multirotor and the fixed-wing, respectively, and faithfully represented cliff geometry. GCP configuration analysis showed that, at least, two stripes of GCPs evenly distributed at different heights are necessary, but three are recommended. The spatial pattern of change between the TLS and the two UAVs datasets was similar. The quantification of the volume of the eroded-accumulated material (using the M3C2 distances and the two UAV datasets) resulted in significant differences as the fixed-wing underestimated the values calculated using the multirotor dataset. The 2.5D strategies used to quantify the volume of change underestimated the eroded volume of the largest rockfalls (compared to the PSR 3D method), which provided the most accurate volume estimates.
Álvaro Gómez-Gutiérrez; Gil Rito Gonçalves. Surveying coastal cliffs using two UAV platforms (multirotor and fixed-wing) and three different approaches for the estimation of volumetric changes. International Journal of Remote Sensing 2020, 41, 8143 -8175.
AMA StyleÁlvaro Gómez-Gutiérrez, Gil Rito Gonçalves. Surveying coastal cliffs using two UAV platforms (multirotor and fixed-wing) and three different approaches for the estimation of volumetric changes. International Journal of Remote Sensing. 2020; 41 (21):8143-8175.
Chicago/Turabian StyleÁlvaro Gómez-Gutiérrez; Gil Rito Gonçalves. 2020. "Surveying coastal cliffs using two UAV platforms (multirotor and fixed-wing) and three different approaches for the estimation of volumetric changes." International Journal of Remote Sensing 41, no. 21: 8143-8175.
Dimensionless morphological ratios (DMR) generally are used in systemic proposals for stream classification and river restoration projects. Often, such morphometric parameters, including field data from channel cross sections, develop into a template for a given geomorphic reference site. In this study, high-resolution Digital Terrain Models (HRDTMs), combined with orthophotographs from 2018 and ground-based surveys, were used to analyze the spatial variability of DMR in a semi-arid ephemeral stream subject to changes in stream power under bankfull conditions. In particular, a channel reach of 2.7 km in length along the Upper Mula stream in southeastern Spain was chosen to test the relationships between the two types of variables. Rosgen's DMR (width to depth ratio, entrenchment ratio, bank height ratio) and hydraulic data at bankfull stage (flow velocity, Froude number, shear stress, mean stream power and energy gradient, among others) were calculated by 1D hydrodynamic modeling and HRDTMs prior entry of field information. The resulting maps allowed comparison of stream power with DMR in relation to the channel stretch class and bed stability. The results showed similar spatial patterns for the width to depth ratio and the bank height ratio. The average values estimated in bend stretches were lower than along straight and slightly sinuous stretches and very similar to those of sub-reaches from the inflection point to the meander bend apex. However, the entrenchment ratio followed a different pattern, according to which the straight and slightly sinuous stretches were the most entrenched and the bend stretches presented a more moderate average entrenchment ratio. In addition, the energy balance and power gradient also experienced spatial variations in relation to the bed stability and DMR. Only in highly incised sub-reaches were such relationships not significant. The lack of a significant correlation between excess energy and bank height ratio or width to depth ratio over short lag distances was also verified, regardless of the affected bedforms. An ANOVA showed important differences between the straight and slightly sinuous stretches and bend stretches, which were strongly influenced by the incision and entrenchment ratios and the maximum bankfull depth.
Carmelo Conesa-García; Pedro Pérez-Cutillas; Rafael García-Lorenzo; Joris Eekhout; Álvaro Gómez-Gutiérrez; Agustín Millares-Valenzuela; Alberto Martínez-Salvador. Dimensionless morphological ratios versus stream power variations at bankfull stage in an ephemeral channel. Geomorphology 2020, 361, 107199 .
AMA StyleCarmelo Conesa-García, Pedro Pérez-Cutillas, Rafael García-Lorenzo, Joris Eekhout, Álvaro Gómez-Gutiérrez, Agustín Millares-Valenzuela, Alberto Martínez-Salvador. Dimensionless morphological ratios versus stream power variations at bankfull stage in an ephemeral channel. Geomorphology. 2020; 361 ():107199.
Chicago/Turabian StyleCarmelo Conesa-García; Pedro Pérez-Cutillas; Rafael García-Lorenzo; Joris Eekhout; Álvaro Gómez-Gutiérrez; Agustín Millares-Valenzuela; Alberto Martínez-Salvador. 2020. "Dimensionless morphological ratios versus stream power variations at bankfull stage in an ephemeral channel." Geomorphology 361, no. : 107199.
Sediments retained in hydrological correction check dams are a useful source of information to understand soil erosion rates and sediment fluxes. Two hundred sixty nine check dams distributed in an area of 239 ha in SW Spain accumulated sediments over a period of 11 to 23 years. The aim of this work is to estimate the volume of sediments deposited in those check dams and to study the spatial variability of the accumulated sediments and its relationships with different environmental variables. The methodology included five steps: 1) flying the study area with a fixed-wing Unmanned Aerial Vehicle to capture high-resolution aerial photographs, 2) Structure-from-Motion photogrammetry, 3) processing the obtained point clouds and Digital Elevation Models (DEMs) to create the current topography and model the past soil surface, 4) estimating the volume of sediments behind each check dam using a topographic technique and 5) exploring the relationship between sediments and different environmental variables. A total of 269 check dams were identified, from which 160 were suitable to quantify the deposited sediment volume. The volume of sediments trapped by individual check-dams ranged from 0 to 108.35 m3, with an average deposition rate of 0.141 m3 ha−1 y−1. The 77% of the check dams retained <1 m3 of sediment. The topographic position and the size of the dam wall played a fundamental role in explaining the differences of total sediment accumulation as well as the deposition rates. Deposition rate was negatively correlated with drainage area, connectivity index, stream power index, topographic wetness index, upstream channel length and the number of upstream check dams. Conversely, deposition rate was positively correlated with the slope of the channel. Those dams located in valley bottoms with longer walls retained more sediment, while those of hillslopes with shorter check dam walls were ineffective.
Alberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel; J. Francisco Lavado Contador; José Juan De Sanjosé Blasco; Manuel Sánchez-Fernánez. sUAS, SfM-MVS photogrammetry and a topographic algorithm method to quantify the volume of sediments retained in check-dams. Science of The Total Environment 2019, 678, 369 -382.
AMA StyleAlberto Alfonso-Torreño, Álvaro Gómez-Gutiérrez, Susanne Schnabel, J. Francisco Lavado Contador, José Juan De Sanjosé Blasco, Manuel Sánchez-Fernánez. sUAS, SfM-MVS photogrammetry and a topographic algorithm method to quantify the volume of sediments retained in check-dams. Science of The Total Environment. 2019; 678 ():369-382.
Chicago/Turabian StyleAlberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel; J. Francisco Lavado Contador; José Juan De Sanjosé Blasco; Manuel Sánchez-Fernánez. 2019. "sUAS, SfM-MVS photogrammetry and a topographic algorithm method to quantify the volume of sediments retained in check-dams." Science of The Total Environment 678, no. : 369-382.
Changes in land use are common in Mediterranean areas and are reported as having produced changes in the intensity of soil erosion. Dehesas are rangelands with a disperse tree cover, widespread in the south‐western part of the Iberian Peninsula and similar ecosystems are also common in other areas with a Mediterranean climate. The aim of the present study is to analyse temporal and spatial variations of soil erosion rates estimated along three hillsides, located in two farms (Buitrera and Parapuños) in southwest Spain. To understand the temporal variation, soil erosion rates were studied in light of land use‐management changes that took place during the last few centuries. Results indicate very low erosion rates prior to the 18th century in both farms. In Buitrera, a first increase of soil loss rates was identified during the period 1831‐1897, amounting to 7.4 t ha‐1 y‐1. A further increase took place during the 20th century, reaching a mean erosion rate of 29.1 t ha‐1 y‐1. In Parapuños, data points to a significant increase from 1881 onwards, with an estimated mean erosion rate of 18.5 t ha‐1 y‐1. Those increases were presumably connected with an intensification of land use, such as cultivation and excessive livestock populations. Regarding spatial variation, the bare surface and the erosive power of run‐off along the hillsides accounts for 76% of the soil erosion rates dispersion. At a local scale, the variability of erosion rates could not be explained, because of (i) uncertainty related to the micromorphology of the past soil surface and (ii) the role of tillage erosion in the past. However, the results obtained offer valuable data on the temporal and spatial variation of erosion rates in dehesas at the hillslope scale and a similar approach could be used for other rangelands with a disperse tree cover.
Judit Rubio‐Delgado; Susanne Schnabel; Álvaro Gómez‐Gutiérrez; Joaquín Francisco Lavado‐Contador. Temporal and spatial variation of soil erosion in wooded rangelands of southwest Spain. Earth Surface Processes and Landforms 2019, 44, 2141 -2155.
AMA StyleJudit Rubio‐Delgado, Susanne Schnabel, Álvaro Gómez‐Gutiérrez, Joaquín Francisco Lavado‐Contador. Temporal and spatial variation of soil erosion in wooded rangelands of southwest Spain. Earth Surface Processes and Landforms. 2019; 44 (11):2141-2155.
Chicago/Turabian StyleJudit Rubio‐Delgado; Susanne Schnabel; Álvaro Gómez‐Gutiérrez; Joaquín Francisco Lavado‐Contador. 2019. "Temporal and spatial variation of soil erosion in wooded rangelands of southwest Spain." Earth Surface Processes and Landforms 44, no. 11: 2141-2155.
Soil degradation by water is a serious environmental problem worldwide, with specific climatic factors being the major causes. We investigated the relationships between synoptic atmospheric patterns (i.e. weather types, WTs) and runoff, erosion and sediment yield throughout the Mediterranean basin by analyzing a large database of natural rainfall events at 68 research sites in 9 countries. Principal Component Analysis (PCA) was used to identify spatial relationships of the different WTs including three hydro-sedimentary variables: rainfall, runoff, and sediment yield (SY, used to refer to both soil erosion measured at plot scale and sediment yield registered at catchment scale). The results indicated 4 spatial classes of rainfall and runoff: (a) northern sites dependent on North (N) and North West (NW) flows; (b) eastern sites dependent on E and NE flows; (c) southern sites dependent on S and SE flows; and, finally, (d) western sites dependent on W and SW flows. Conversely, three spatial classes are identified for SY characterized by: (a) N and NE flows in northern sites (b) E flows in eastern sites, and (c) W and SW flows in western sites. Most of the rainfall, runoff and SY occurred during a small number of daily events, and just a few WTs accounted for large percentages of the total. Our results confirm that characterization by WT improves understanding of the general conditions under which runoff and SY occur, and provides useful information for understanding the spatial variability of runoff, and SY throughout the Mediterranean basin. The approach used here could be useful to aid of the design of regional water management and soil conservation measures.
D. Peña-Angulo; E. Nadal-Romero; J.C. González-Hidalgo; Juan Albaladejo; V. Andreu; V. Bagarello; H. Barhi; R.J. Batalla; Susana Bernal; R. Bienes; J. Campo; M.A. Campo-Bescós; A. Canatario-Duarte; Y. Cantón; J. Casali; Victor M Castillo; A. Cerdà; A. Cheggour; P. Cid; N. Cortesi; G. Desir; E. Díaz-Pereira; T. Espigares; J. Estrany; M. Fernández-Raga; C.S.S. Ferreira; V. Ferro; F. Gallart; R. Giménez; E. Gimeno; J.A. Gómez; A. Gómez-Gutiérrez; H. Gómez-Macpherson; O. González-Pelayo; P. Hueso-González; O. Kairis; G.P. Karatzas; S. Klotz; C. Kosmas; N. Lana-Renault; T. Lasanta; J. Latron; R. Lázaro; Y. Le Bissonnais; C. Le Bouteiller; F. Licciardello; J.A. López-Tarazón; Ana Lucía; C. Marín; M.J. Marqués; J. Martínez-Fernández; M. Martínez-Mena; J.F. Martínez-Murillo; L. Mateos; N. Mathys; L. Merino-Martín; M. Moreno-De Las Heras; N. Moustakas; J.M. Nicolau; A. Novara; V. Pampalone; D. Raclot; M.L. Rodríguez-Blanco; J. Rodrigo-Comino; A. Romero-Díaz; E. Roose; J.L. Rubio; J.D. Ruiz-Sinoga; Susanne Schnabel; J.M. Senciales-González; V. Simonneaux; A. Solé-Benet; E.V. Taguas; M.M. Taboada-Castro; F. Todisco; X. Úbeda; E.A. Varouchakis; D. Vericat; L. Wittenberg; Ane Zabaleta; M. Zorn. Spatial variability of the relationships of runoff and sediment yield with weather types throughout the Mediterranean basin. Journal of Hydrology 2019, 571, 390 -405.
AMA StyleD. Peña-Angulo, E. Nadal-Romero, J.C. González-Hidalgo, Juan Albaladejo, V. Andreu, V. Bagarello, H. Barhi, R.J. Batalla, Susana Bernal, R. Bienes, J. Campo, M.A. Campo-Bescós, A. Canatario-Duarte, Y. Cantón, J. Casali, Victor M Castillo, A. Cerdà, A. Cheggour, P. Cid, N. Cortesi, G. Desir, E. Díaz-Pereira, T. Espigares, J. Estrany, M. Fernández-Raga, C.S.S. Ferreira, V. Ferro, F. Gallart, R. Giménez, E. Gimeno, J.A. Gómez, A. Gómez-Gutiérrez, H. Gómez-Macpherson, O. González-Pelayo, P. Hueso-González, O. Kairis, G.P. Karatzas, S. Klotz, C. Kosmas, N. Lana-Renault, T. Lasanta, J. Latron, R. Lázaro, Y. Le Bissonnais, C. Le Bouteiller, F. Licciardello, J.A. López-Tarazón, Ana Lucía, C. Marín, M.J. Marqués, J. Martínez-Fernández, M. Martínez-Mena, J.F. Martínez-Murillo, L. Mateos, N. Mathys, L. Merino-Martín, M. Moreno-De Las Heras, N. Moustakas, J.M. Nicolau, A. Novara, V. Pampalone, D. Raclot, M.L. Rodríguez-Blanco, J. Rodrigo-Comino, A. Romero-Díaz, E. Roose, J.L. Rubio, J.D. Ruiz-Sinoga, Susanne Schnabel, J.M. Senciales-González, V. Simonneaux, A. Solé-Benet, E.V. Taguas, M.M. Taboada-Castro, F. Todisco, X. Úbeda, E.A. Varouchakis, D. Vericat, L. Wittenberg, Ane Zabaleta, M. Zorn. Spatial variability of the relationships of runoff and sediment yield with weather types throughout the Mediterranean basin. Journal of Hydrology. 2019; 571 ():390-405.
Chicago/Turabian StyleD. Peña-Angulo; E. Nadal-Romero; J.C. González-Hidalgo; Juan Albaladejo; V. Andreu; V. Bagarello; H. Barhi; R.J. Batalla; Susana Bernal; R. Bienes; J. Campo; M.A. Campo-Bescós; A. Canatario-Duarte; Y. Cantón; J. Casali; Victor M Castillo; A. Cerdà; A. Cheggour; P. Cid; N. Cortesi; G. Desir; E. Díaz-Pereira; T. Espigares; J. Estrany; M. Fernández-Raga; C.S.S. Ferreira; V. Ferro; F. Gallart; R. Giménez; E. Gimeno; J.A. Gómez; A. Gómez-Gutiérrez; H. Gómez-Macpherson; O. González-Pelayo; P. Hueso-González; O. Kairis; G.P. Karatzas; S. Klotz; C. Kosmas; N. Lana-Renault; T. Lasanta; J. Latron; R. Lázaro; Y. Le Bissonnais; C. Le Bouteiller; F. Licciardello; J.A. López-Tarazón; Ana Lucía; C. Marín; M.J. Marqués; J. Martínez-Fernández; M. Martínez-Mena; J.F. Martínez-Murillo; L. Mateos; N. Mathys; L. Merino-Martín; M. Moreno-De Las Heras; N. Moustakas; J.M. Nicolau; A. Novara; V. Pampalone; D. Raclot; M.L. Rodríguez-Blanco; J. Rodrigo-Comino; A. Romero-Díaz; E. Roose; J.L. Rubio; J.D. Ruiz-Sinoga; Susanne Schnabel; J.M. Senciales-González; V. Simonneaux; A. Solé-Benet; E.V. Taguas; M.M. Taboada-Castro; F. Todisco; X. Úbeda; E.A. Varouchakis; D. Vericat; L. Wittenberg; Ane Zabaleta; M. Zorn. 2019. "Spatial variability of the relationships of runoff and sediment yield with weather types throughout the Mediterranean basin." Journal of Hydrology 571, no. : 390-405.
Rangeland (known as Dehesas or Montados) is a characteristic ecosystem of the southwestern part of the Iberian Peninsula that occupies approximately 3.5 million ha, representing the most important agrosilvopastoral system in Europe. Nowadays, this situation is changing, being under circumstances of threat due to different aspects that are causing degradation of holm oaks and cork oaks throughout the Iberian Peninsula. These problems are of various kinds, accentuating the disease or syndrome of seca, tree death caused by Phytophthora cinnamomi. For the development of death susceptibility models, maximum entropy algorithms (MAXENT) were used, often widely used in ecological niche models. In the development of models, a wide range of variables (dependents and predictive), both climatic or bioclimatic, geological or soil, vegetation and economic and geographical characteristics were used. The study was carried out at two scales, the Autonomous Community of Extremadura in its entirety, and another more specific work scale, such as seca focus in protected natural areas within the Natura 2000 Network. The regional model showed a total of 1,179,639 ha prone to be affected by this condition, among which, 383,339 ha showed a high potential risk level of seca presence. These models, carried out at local scale in 4 polygons selected within the Natura 2000 Network, showed more than 70% of the land surface studied as areas with risk of suffering seca.
Álvaro Tejeda-Corvillo; Jesús Barrena-González; Joaquín Francisco Lavado-Contador; Alberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Manuel Pulido-Fernández. Spatial Models Predictive of “Seca” Risk in Extremadura. Applications at Regional and Local Scale in Protected Natural Areas. Proceedings 2019, 30, 58 .
AMA StyleÁlvaro Tejeda-Corvillo, Jesús Barrena-González, Joaquín Francisco Lavado-Contador, Alberto Alfonso-Torreño, Álvaro Gómez-Gutiérrez, Manuel Pulido-Fernández. Spatial Models Predictive of “Seca” Risk in Extremadura. Applications at Regional and Local Scale in Protected Natural Areas. Proceedings. 2019; 30 (1):58.
Chicago/Turabian StyleÁlvaro Tejeda-Corvillo; Jesús Barrena-González; Joaquín Francisco Lavado-Contador; Alberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Manuel Pulido-Fernández. 2019. "Spatial Models Predictive of “Seca” Risk in Extremadura. Applications at Regional and Local Scale in Protected Natural Areas." Proceedings 30, no. 1: 58.
Gully erosion in valley bottoms is a frequent process with negative consequences in the dehesa environment. Soil loss, decrease of soil and descend in biomass are among the negative aftereffect of gully erosion processes. Studies conducted in agrosilvopastoral systems described the dynamics of gullied channels by means of fixed topographic cross sections or with low spatial resolution Digital Elevation Models (DEMs). Currently, high spatial and temporal resolution DEMs can be produced with spatially distributed information due to the development of new systems, platforms and sensors. Additionally, the rainfall and sediment discharge could also be monitored. This control allows us to relate gully erosion with catchment hydrology. The goals are (1) to quantify the sediment budgets by the spatio-temporal distribution of erosion and/or deposition in the gullied channel, (2) to interpret the geomorphic processes driving erosion and deposition and (3) to analyze the relationship between the morphological change and the catchment runoff and the sediment load. The studied area is a gullied channel located in the SW Iberian Peninsula and developed over a recent sedimentary deposit. The channel reaches an extension of 1 km in length and 2 m in depth. The methodology included the following steps: (1) flying the same study area with different time periods using a fixed-wing small Unmanned Aerial System (sUAS) to capture high-resolution aerial images and surveying Ground Control Points (GCPs) using a GNSS, (2) Structure-from-Motion photogrammetry processing using the acquired images and the GCPs to produce high-resolution DEMs for each date, (3) Applying the DEMs of difference approach to estimate topographic changes and to quantify the sediment budget and finally (4) analyzing the relationship between rainfall events, discharge, sediment load and changes in the channel previously estimated. Resulting DEMs and orthophotographs showed a Ground Sampling Distance of 0.02 m with a georeferencing Root Mean Square Error of 0.03 m. A spatially variable threshold (to differentiate actual geomorphic change from noise or errors) was produced using a Fuzzy Inference System and considering photogrammetric errors, slope and vegetation as factors. The applied method proved to be suitable to interpret the geomorphic changes for the gullied channel. For the 2016–2018 period, the gully showed a positive balance indicating accumulation of sediments coming from the hillslopes of the catchment. It is the period with the highest rainfall when numerous events generated runoff. On the contrary, for the period 2018–2019 a total soil loss of −119 m3 was estimated.
Alberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel; J. Francisco Lavado Contador; Manuel Pulido Fernández; Jesús Barrena-González. Monitoring Geomorphic Change and Catchment Sediment Production to Understand the Erosive Dynamics in a Gullied Channel by Means of High-Resolution DEMs. Proceedings 2019, 30, 56 .
AMA StyleAlberto Alfonso-Torreño, Álvaro Gómez-Gutiérrez, Susanne Schnabel, J. Francisco Lavado Contador, Manuel Pulido Fernández, Jesús Barrena-González. Monitoring Geomorphic Change and Catchment Sediment Production to Understand the Erosive Dynamics in a Gullied Channel by Means of High-Resolution DEMs. Proceedings. 2019; 30 (1):56.
Chicago/Turabian StyleAlberto Alfonso-Torreño; Álvaro Gómez-Gutiérrez; Susanne Schnabel; J. Francisco Lavado Contador; Manuel Pulido Fernández; Jesús Barrena-González. 2019. "Monitoring Geomorphic Change and Catchment Sediment Production to Understand the Erosive Dynamics in a Gullied Channel by Means of High-Resolution DEMs." Proceedings 30, no. 1: 56.
Soil moisture has a direct influence on biomass production, food security and ecosystem functioning, thus resources management in water‐limited environments could be improved if feedbacks between water and vegetation were fully understood. This study tries to define the sensitivity of annual pastures under the influence of different vegetation covers to soil water availability during two contrasting growing seasons, dry and wet. For this reason, soil water content was continuously monitored during two complete hydrological years using capacitance sensors, which were gathered in soil moisture stations located in open grasslands and beneath tree canopies. Pasture growth was recorded by measurements of its height and by biomass cuts. The study was conducted on three private farms located in savanna‐like ecosystems of Spain (dehesa) with Mediterranean climate. Results highlighted the importance of the topsoil (first 15 cm) as the main layer for water supply of natural grasses. Soils below canopies registered longer and more intense water deficits than those located in grasslands. This was reflected in biomass growth, given that when growing conditions were dry, pasture yield decreased more than 40% in grasslands and more than 50% below tree canopies. The studied ecosystems occupy millions of hectares in Spain and Portugal and present a canopy cover up to 40%. If dry episodes become more frequent in the present century due to climate change an important surface, especially under trees, could become drier, less productive and, therefore, more prone to land degradation.
Javier Lozano-Parra; Susanne Schnabel; Manuel Pulido; Álvaro Gómez-Gutiérrez; Francisco Lavado-Contador. Effects of soil moisture and vegetation cover on biomass growth in water‐limited environments. Land Degradation & Development 2018, 29, 4405 -4414.
AMA StyleJavier Lozano-Parra, Susanne Schnabel, Manuel Pulido, Álvaro Gómez-Gutiérrez, Francisco Lavado-Contador. Effects of soil moisture and vegetation cover on biomass growth in water‐limited environments. Land Degradation & Development. 2018; 29 (12):4405-4414.
Chicago/Turabian StyleJavier Lozano-Parra; Susanne Schnabel; Manuel Pulido; Álvaro Gómez-Gutiérrez; Francisco Lavado-Contador. 2018. "Effects of soil moisture and vegetation cover on biomass growth in water‐limited environments." Land Degradation & Development 29, no. 12: 4405-4414.
Gully erosion in agrosilvopastoral systems of SW Spain represents a common degradation process, but has been hardly analysed. The suitability of using the Unmanned Aerial Vehicles (UAV) and Structure from Motion photogrammetry (SfM) workflow to map small valley-bottom gullies in these landscapes was tested. The results showed centimetre-level accuracy. Observed strengths and limitations of the UAV+SfM workflow in the study areas are discussed. The resulting cartography allowed mapping soil erosion forms at outstanding spatial scales. All study areas showed evidences of degradation.
Álvaro Gómez Gutiérrez; Susanne Schnabel; Francisco Lavado Contador; José Juan De Sanjosé; Alan D. J. Atkinson; Manuel Pulido Fernández. Studying the influence of livestock pressure on gully erosion in rangelands of SW Spain by means of the UAV+SfM workflow. Boletín de la Asociación de Geógrafos Españoles 2018, 66 -88.
AMA StyleÁlvaro Gómez Gutiérrez, Susanne Schnabel, Francisco Lavado Contador, José Juan De Sanjosé, Alan D. J. Atkinson, Manuel Pulido Fernández. Studying the influence of livestock pressure on gully erosion in rangelands of SW Spain by means of the UAV+SfM workflow. Boletín de la Asociación de Geógrafos Españoles. 2018; (78):66-88.
Chicago/Turabian StyleÁlvaro Gómez Gutiérrez; Susanne Schnabel; Francisco Lavado Contador; José Juan De Sanjosé; Alan D. J. Atkinson; Manuel Pulido Fernández. 2018. "Studying the influence of livestock pressure on gully erosion in rangelands of SW Spain by means of the UAV+SfM workflow." Boletín de la Asociación de Geógrafos Españoles , no. 78: 66-88.
Debris talus is a very common landform in the temperate high mountain, so much so that it is the most representative of the periglacial and nival processes. This work studies debris cones in the Picos de Europa, an Atlantic mountain range in the north of the Iberian Peninsula. A detailed geomorphological map was prepared, fieldwork was carried out on the debris cone surface, the ground and air thermal regime was analyzed, and a five-year Terrestrial Laser Scan survey carried out. Annual volume changes on the surface of the debris cones were detected and related to active processes and sediment transfer. Two different behaviors were observed in each cone. Cone A is linear, with equilibrium between accumulation and sediment transfer, while Cone B is concave-convex denoting accumulation processes in the upper part deriving from the greater frequency of snow avalanches. Changes in morphology surpass 50 cm/year with most of the activity taking place in the highest and lowest areas. The presence and action of the ice on the debris slope are moderate or non-existent and freeze-thaw processes are only active on the walls at over 2000 m a.s.l. The main processes on debris cones are debris flow and creep related to snowcover, but sediment transfer on the slopes involves high intensity-low frequency (debris flow, avalanches) and high frequency-low intensity processes (creep, shift, solifluction and wasting).
Enrique Serrano; José Juan Sanjosé; Álvaro Gómez-Gutiérrez; Manuel Gómez-Lende. Surface movement and cascade processes on debris cones in temperate high mountain (Picos de Europa, northern Spain). Science of The Total Environment 2018, 649, 1323 -1337.
AMA StyleEnrique Serrano, José Juan Sanjosé, Álvaro Gómez-Gutiérrez, Manuel Gómez-Lende. Surface movement and cascade processes on debris cones in temperate high mountain (Picos de Europa, northern Spain). Science of The Total Environment. 2018; 649 ():1323-1337.
Chicago/Turabian StyleEnrique Serrano; José Juan Sanjosé; Álvaro Gómez-Gutiérrez; Manuel Gómez-Lende. 2018. "Surface movement and cascade processes on debris cones in temperate high mountain (Picos de Europa, northern Spain)." Science of The Total Environment 649, no. : 1323-1337.
Structure-from-Motion (SfM) photogrammetry is one of the most common approaches used to elaborate high-resolution Digital Elevation Models (DEMs) nowadays. Factors that influence the final error associated to the derived DEM are: camera-to-ground distance, camera-sensor system parameters, image network geometry, matching performance, terrain type, lighting conditions and referencing methods. Here, a strategy focused on minimizing the occlusion produced by topography and determine optimal camera locations for image acquisition is presented. This methodology is based on using a viewshed analysis implemented in a Geographical Information System (GIS) to identify the best images for the SfM workflow of a specific survey-site. The suitability of the workflow presented against conventional acquisition strategies was tested using three different datasets (one terrestrial and two aerial) and analyzing differences between SfM-derived DEM produced using: 1) a dataset acquired following conventional overlap requirements (i.e. one image every 5-10º around the target for terrestrial close-range oblique SfM and 70-60% frontal and side overlap for aerial surveys), 2) a dataset overloaded with images (i.e. one image every 3-4º around the target and >95-95% frontal and side overlap for aerial surveys), and 3) images selected using the viewshed analysis. The resulting DEMs were tested against Terrestrial Laser Scanner-derived (TLS) DEMs. SfM results showed denser point clouds for the datasets elaborated using the viewshed analysis. Differences were particularly important for the terrestrial case indicating a stronger line-of-sight effect on the ground. Point cloud density absolute differences and no-data zones in the datasets produced using the conventional strategies resulted in larger Mean Absolute Errors (MAE) in the DEMs. DEMs produced using the viewshed criteria showed lower MAEs than the conventional dataset and similar to the dataset overloaded of images. Additionally, the processing time of the datasets that used viewshed criteria was much shorter than the datasets overloaded of images.
Alvaro Gomez-Gutierrez; Trent Biggs; Napoleon Gudino-Elizondo; Paz Errea Abad; Esteban Alonso-González; Estela Nadal-Romero; José Juan De Sanjosé Blasco. Elaborating more accurate high-resolution DEMs using SfM workflow. 2018, 1 .
AMA StyleAlvaro Gomez-Gutierrez, Trent Biggs, Napoleon Gudino-Elizondo, Paz Errea Abad, Esteban Alonso-González, Estela Nadal-Romero, José Juan De Sanjosé Blasco. Elaborating more accurate high-resolution DEMs using SfM workflow. . 2018; ():1.
Chicago/Turabian StyleAlvaro Gomez-Gutierrez; Trent Biggs; Napoleon Gudino-Elizondo; Paz Errea Abad; Esteban Alonso-González; Estela Nadal-Romero; José Juan De Sanjosé Blasco. 2018. "Elaborating more accurate high-resolution DEMs using SfM workflow." , no. : 1.
Structure-from-Motion (SfM) photogrammetry is one of the most common approaches used to elaborate high-resolution Digital Elevation Models (DEMs) nowadays. Factors that influence the final error associated to the derived DEM are: camera-to-ground distance, camera-sensor system parameters, image network geometry, matching performance, terrain type, lighting conditions and referencing methods. Here, a strategy focused on minimizing the occlusion produced by topography and determine optimal camera locations for image acquisition is presented. This methodology is based on using a viewshed analysis implemented in a Geographical Information System (GIS) to identify the best images for the SfM workflow of a specific survey-site. The suitability of the workflow presented against conventional acquisition strategies was tested using three different datasets (one terrestrial and two aerial) and analyzing differences between SfM-derived DEM produced using: 1) a dataset acquired following conventional overlap requirements (i.e. one image every 5-10º around the target for terrestrial close-range oblique SfM and 70-60% frontal and side overlap for aerial surveys), 2) a dataset overloaded with images (i.e. one image every 3-4º around the target and >95-95% frontal and side overlap for aerial surveys), and 3) images selected using the viewshed analysis. The resulting DEMs were tested against Terrestrial Laser Scanner-derived (TLS) DEMs. SfM results showed denser point clouds for the datasets elaborated using the viewshed analysis. Differences were particularly important for the terrestrial case indicating a stronger line-of-sight effect on the ground. Point cloud density absolute differences and no-data zones in the datasets produced using the conventional strategies resulted in larger Mean Absolute Errors (MAE) in the DEMs. DEMs produced using the viewshed criteria showed lower MAEs than the conventional dataset and similar to the dataset overloaded of images. Additionally, the processing time of the datasets that used viewshed criteria was much shorter than the datasets overloaded of images.
Alvaro Gomez-Gutierrez; Trent Biggs; Napoleon Gudino-Elizondo; Paz Errea Abad; Esteban Alonso-González; Estela Nadal-Romero; José Juan De Sanjosé Blasco. Elaborating more accurate high-resolution DEMs using SfM workflow. 2018, 1 .
AMA StyleAlvaro Gomez-Gutierrez, Trent Biggs, Napoleon Gudino-Elizondo, Paz Errea Abad, Esteban Alonso-González, Estela Nadal-Romero, José Juan De Sanjosé Blasco. Elaborating more accurate high-resolution DEMs using SfM workflow. . 2018; ():1.
Chicago/Turabian StyleAlvaro Gomez-Gutierrez; Trent Biggs; Napoleon Gudino-Elizondo; Paz Errea Abad; Esteban Alonso-González; Estela Nadal-Romero; José Juan De Sanjosé Blasco. 2018. "Elaborating more accurate high-resolution DEMs using SfM workflow." , no. : 1.
Judit Rubio-Delgado; Susanne Schnabel; Álvaro Gómez-Gutiérrez; Manuel Sánchez-Fernández. Estimation of soil erosion rates in dehesas using the inflection point of holm oaks. CATENA 2018, 166, 56 -67.
AMA StyleJudit Rubio-Delgado, Susanne Schnabel, Álvaro Gómez-Gutiérrez, Manuel Sánchez-Fernández. Estimation of soil erosion rates in dehesas using the inflection point of holm oaks. CATENA. 2018; 166 ():56-67.
Chicago/Turabian StyleJudit Rubio-Delgado; Susanne Schnabel; Álvaro Gómez-Gutiérrez; Manuel Sánchez-Fernández. 2018. "Estimation of soil erosion rates in dehesas using the inflection point of holm oaks." CATENA 166, no. : 56-67.