Understanding soil profiles and sediment redistribution over long time scales in an agrarian setting: the case of Lauwerdal (Northern France)

Soil erosion constitutes a major problem in the European loess belt. From England to Eastern Europe, loess-derived soils are particularly susceptible to water and tillage erosion. This is certainly the case for the Aa River Basin (Nord-Pas-de-Calais, northern France), where a relatively thin Pleistocene loess cover is present on top of a substrate of clay-with-flints and Cretaceous chalk. This research aimed at quantifying the amount of soil eroded since its initiation. Making a gross balance of the soil erosion and sedimentation processes intends to study the evolution of the soil surface and the effects of different types of erosion over longer periods of time, and quantify erosion rates in agricultural areas.The extent and amount of eroded soil was mapped in the Lauwerdal, a 63 ha large catchment in the headwaters of the Aa River Basin (Northern France). Based on four soil profiles, described and sampled along a topographic transect, and 256 augerings spaced along a grid, the original soil surface level was reconstructed. The current topographic surface was analysed based on a Digital Terrain Model obtained from UAV aerial photographs. The organic matter present in the filling of a former erosion channel, observed in one of the soil profiles, was dated by 14C as an indication of the onset of the erosion and sedimentation process.Water and tillage erosion are the main processes characterizing the study area: eroded soils (Nudiargic Luvisols) dominate the upper reaches of the study area with colluvium at the footslopes (Colluvic Regosols). The sediment budget reveals that the bulk of the sediments are discharged from the headwater catchment as the quantity of eroded soil (0.87 &#215; 106 tonnes) is more than a ten-fold higher than the deposition (0.068 &#215; 106 tonnes). The 14C dating indicates that the erosion channels started filling up between the Early Iron Age and the Roman period, ca. 1200 years BP. The historical erosion rates are estimated at 491.4 t/km2 per year, and deposition rates at 91.8 t/km2 per year.Our findings illustrate how the amount of soil eroded over a long time span can be estimated from soil morphologic features in combination with a detailed Digital Terrain Model. Indeed, human induced soil erosion dates back at least to Early Iron Age, when forest clearing for agricultural expanded. Surely, the mechanization and upscaling of agriculture in the 20th century will have exacerbated this process. The results also show that sediments are evacuated from headwater catchments and, consequently, must accumulate in the lower alluvial plains. Our findings corroborate research findings from the silt-loess belt of central Belgium where it was shown that soil erosion started in the same period and also led to the formation of wide alluvial valleys.

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Modeling Streamflow and Sediment Loads with a Photogrammetrically Derived UAS Digital Terrain Model: Empirical Evaluation from a Fluvial Aggregate Excavation Operation

Drones ◽

10.3390/drones5010020 ◽

2021 ◽

Vol 5 (1) ◽

pp. 20

Author(s):

Joseph P. Hupy ◽

Cyril O. Wilson

Keyword(s):

Soil Erosion ◽

Point Cloud ◽

Empirical Evaluation ◽

Digital Terrain Model ◽

Surface Flow ◽

Sediment Loading ◽

Terrain Model ◽

Digital Terrain ◽

Statistical Measures ◽

Geospatial Datasets

Soil erosion monitoring is a pivotal exercise at macro through micro landscape levels, which directly informs environmental management at diverse spatial and temporal scales. The monitoring of soil erosion can be an arduous task when completed through ground-based surveys and there are uncertainties associated with the use of large-scale medium resolution image-based digital elevation models for estimating erosion rates. LiDAR derived elevation models have proven effective in modeling erosion, but such data proves costly to obtain, process, and analyze. The proliferation of images and other geospatial datasets generated by unmanned aerial systems (UAS) is increasingly able to reveal additional nuances that traditional geospatial datasets were not able to obtain due to the former’s higher spatial resolution. This study evaluated the efficacy of a UAS derived digital terrain model (DTM) to estimate surface flow and sediment loading in a fluvial aggregate excavation operation in Waukesha County, Wisconsin. A nested scale distributed hydrologic flow and sediment loading model was constructed for the UAS point cloud derived DTM. To evaluate the effectiveness of flow and sediment loading generated by the UAS point cloud derived DTM, a LiDAR derived DTM was used for comparison in consonance with several statistical measures of model efficiency. Results demonstrate that the UAS derived DTM can be used in modeling flow and sediment erosion estimation across space in the absence of a LiDAR-based derived DTM.

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Analysis of Mountain Relief for the Causes of Snow Avalanches

Journal of Geology Geography and Geoecology ◽

10.15421/112071 ◽

2020 ◽

Vol 29 (4) ◽

pp. 789-795

Author(s):

Roman M. Rudyi ◽

Yuriy O. Kyselov ◽

Halyna T. Domashenko ◽

Olena Y. Kravets ◽

Kateryna D. Husar

Keyword(s):

Solar Radiation ◽

Digital Terrain Model ◽

Mountain Range ◽

Mountain Area ◽

Terrain Model ◽

Gis Technologies ◽

Digital Terrain ◽

Solar Radiation Incident ◽

Long Time ◽

Fundamental Research

The descent of avalanches is quite a usual phenomenon for the Ukrainian Carpathians, as well as for the conditions of mountain terrain in general. The Gorgany range of the Carpathian mountains is a typical avalanche-prone territory. Avalanches cause significant damage to forestry and may lead to casualties. Therefore, descent of avalanches has for a long time been a subject of fundamental research in geomorphology, meteorology, topography, photogrammetry and GIS technologies. Using photogrammetric mapping, we analyzed the causes of the descent of one of the largest avalanches in the Ukrainian Carpathians for the past 15 years. The avalanche fell from Poliensky mountain in the Gorgany mountain range in 2006, causing destruction of a great amount of forest. The main causes of avalanches were divided into two groups, the first including more or less stable factors caused by impact of terrain and somewhat less by solar radiation and the second group comprising meteorological factors, such as prolonged snowstorms and snowfall, that is, different fluctuations in weather. The main attention was paid to the first group of factors. For this purpose, a digital terrain model (DTM) of the study area was developed, visualizing the terrain, demonstrating the studied slope of the mountain along which the avalanche slid. According to the digital model, we developed maps of the steepness andexposition of the slope. Also we calculated the coefficient for solar radiation incident on the slope and which depends on the height of the Sun above the horizon and the coordinates of the slope. Using these data, the illuminance map of the Poliensky mountain area was developed. Studies conducted using GIS technologies led to the conclusion that the determining factors that triggered the powerful avalanche from Poliensky mountain were the great steepness and length of the slope, as well as the absence of forest at the top of the mountain, i.e. at the beginning of the avalanche track.

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Individualization of soil classes by disaggregation of physiographic map polygons

Pesquisa Agropecuária Brasileira ◽

10.1590/s1678-3921.pab2019.v54.00290 ◽

2019 ◽

Vol 54 ◽

Author(s):

José Janderson Ferreira Costa ◽

Elvio Giasson ◽

Elisângela Benedet da Silva ◽

Alcinei Ribeiro Campos ◽

Israel Rosa Machado ◽

...

Keyword(s):

Digital Terrain Model ◽

Soil Profiles ◽

Soil Maps ◽

Physiographic Unit ◽

Tree Model ◽

Soil Map ◽

Terrain Model ◽

Digital Terrain ◽

Cross Tabulation ◽

Geomorphometric Parameters

Abstract: The objective of this work was to disaggregate the polygons of physiographic map units in order to individualize the soil classes in each one, representing them as simple soil map units and generating a more detailed soil map than the original one, making these data more useful for future reference. A physiographic map, on a 1:25,000 scale, of the Tarumãzinho watershed, located in the municipality of Águas Frias, in the state of Santa Catarina, Brazil, was used. For disaggregation, three geomorphometric parameters were applied: slope and landforms, both derived from the digital terrain model; and an elevation map. The boundaries of the physiographic units and the elevation, slope, and landform maps were subjected to cross tabulation to identify the existing combinations between the soil classes of each physiographic unit. Based on these combinations, rules were established to select typical areas of occurrence of each soil type in order to train a decision tree model to predict the occurrence of soil classes. The model was trained using the Weka software and was validated with a set of georeferenced soil profiles. Disaggregation enables the individualization and spatialization of soil classes and is useful in producing detailed soil maps.

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Applied spatial analytic tools in orchards with special regard to agro-ecology

International Journal of Horticultural Science ◽

10.31421/ijhs/17/1-2./938 ◽

2011 ◽

Vol 17 (1-2) ◽

Author(s):

T. Fórián ◽

A. Nagy ◽

J. Tamás ◽

Z. Szabó ◽

M. Soltész ◽

...

Keyword(s):

Digital Elevation Model ◽

Digital Terrain Model ◽

Analytical Techniques ◽

Soil Surface ◽

Terrain Model ◽

Digital Terrain ◽

Contour Lines ◽

Digital Elevation ◽

Elevation Model ◽

Fruit Orchards

Our investigation was carried out in several orchards in Hungary. This study reviews applicability of the different spatial analytical techniques in orchard especially models based on surface relief, such as digital elevation model, digital terrain model, slope and aspect maps. In recent time, the generation of digital elevation model has become a popular examination method. However, the elevation models generated from contour lines or elevation points could be applied to evaluate agro- ecological potential of fruit orchards to some extent. The highest deficiency of these models is the fact that these show the altitude of soil surface only and do not demonstrate landmarks on the surface. Consequently, the calculation of the radiation value results data relating to soil surface. The terrain model generated and applied by our team demonstrates fine surface texture and the landmarks in the orchard, so it is suitable for further examination.

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Geographic information system (GIS) procedure for preliminary delineation of debris-flow hazard areas from a digital terrain model, Madison County, Virginia

Open-File Report ◽

10.3133/ofr99336 ◽

1999 ◽

Author(s):

R.H. Campbell ◽

P.G. Chirico

Keyword(s):

Information System ◽

Geographic Information System ◽

Debris Flow ◽

Digital Terrain Model ◽

Geographic Information ◽

Terrain Model ◽

Madison County ◽

Digital Terrain ◽

Debris Flow Hazard

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The Effect of LiDAR Sampling Density on DTM Accuracy for Areas with Heavy Forest Cover

Forests ◽

10.3390/f12030265 ◽

2021 ◽

Vol 12 (3) ◽

pp. 265

Author(s):

Mihnea Cățeanu ◽

Arcadie Ciubotaru

Keyword(s):

Forest Cover ◽

Initial Point ◽

Ground Surface ◽

Digital Terrain Model ◽

Morphological Data ◽

Sampling Density ◽

Terrain Model ◽

Digital Terrain ◽

Point Density ◽

The Impact

Laser scanning via LiDAR is a powerful technique for collecting data necessary for Digital Terrain Model (DTM) generation, even in densely forested areas. LiDAR observations located at the ground level can be separated from the initial point cloud and used as input for the generation of a Digital Terrain Model (DTM) via interpolation. This paper proposes a quantitative analysis of the accuracy of DTMs (and derived slope maps) obtained from LiDAR data and is focused on conditions common to most forestry activities (rough, steep terrain with forest cover). Three interpolation algorithms were tested: Inverse Distance Weighted (IDW), Natural Neighbour (NN) and Thin-Plate Spline (TPS). Research was mainly focused on the issue of point data density. To analyze its impact on the quality of ground surface modelling, the density of the filtered data set was artificially lowered (from 0.89 to 0.09 points/m2) by randomly removing point observations in 10% increments. This provides a comprehensive method of evaluating the impact of LiDAR ground point density on DTM accuracy. While the reduction of point density leads to a less accurate DTM in all cases (as expected), the exact pattern varies by algorithm. The accuracy of the LiDAR-derived DTMs is relatively good even when LiDAR sampling density is reduced to 0.40–0.50 points/m2 (50–60 % of the initial point density), as long as a suitable interpolation algorithm is used (as IDW proved to be less resilient to density reductions below approximately 0.60 points/m2). In the case of slope estimation, the pattern is relatively similar, except the difference in accuracy between IDW and the other two algorithms is even more pronounced than in the case of DTM accuracy. Based on this research, we conclude that LiDAR is an adequate method for collecting morphological data necessary for modelling the ground surface, even when the sampling density is significantly reduced.

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DTM-based analysis of the spatial distribution of topolineaments

Open Geosciences ◽

10.1515/geo-2020-0059 ◽

2020 ◽

Vol 12 (1) ◽

pp. 1185-1199

Author(s):

Mirosław Kamiński

Keyword(s):

Laser Scanning ◽

Digital Terrain Model ◽

Research Area ◽

Tectonic Structures ◽

Empirical Bayesian ◽

Scanning Method ◽

Empirical Bayesian Kriging ◽

Terrain Model ◽

Digital Terrain ◽

Airborne Laser

AbstractThe research area is located on the boundary between two Paleozoic structural units: the Radom–Kraśnik Block and the Mazovian–Lublin Basin in the southeastern Poland. The tectonic structures are separated by the Ursynów–Kazimierz Dolny fault zone. The digital terrain model obtained by the ALS (Airborne Laser Scanning) method was used. Classification and filtration of an elevation point cloud were performed. Then, from the elevation points representing only surfaces, a digital terrain model was generated. The model was used to visually interpret the course of topolineaments and their automatic extraction from DTM. Two topolineament systems, trending NE–SW and NW–SE, were interpreted. Using the kernel density algorithm, topolineament density models were generated. Using the Empirical Bayesian Kriging, a thickness model of quaternary deposits was generated. A relationship was observed between the course of topolineaments and the distribution and thickness of Quaternary formations. The topolineaments were compared with fault directions marked on tectonic maps of the Paleozoic and Mesozoic. Data validation showed consistency between topolineaments and tectonic faults. The obtained results are encouraging for further research.

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Production, Validation and Morphometric Analysis of a Digital Terrain Model for Lake Trichonis Using Geospatial Technologies and Hydroacoustics

ISPRS International Journal of Geo-Information ◽

10.3390/ijgi10020091 ◽

2021 ◽

Vol 10 (2) ◽

pp. 91

Author(s):

Triantafyllia-Maria Perivolioti ◽

Antonios Mouratidis ◽

Dimitrios Terzopoulos ◽

Panagiotis Kalaitzis ◽

Dimitrios Ampatzidis ◽

...

Keyword(s):

Morphometric Analysis ◽

Ad Hoc ◽

Regional Scale ◽

Digital Terrain Model ◽

Relevant Information ◽

Relative Difference ◽

Systematic Observation ◽

Qualitative And Quantitative ◽

Terrain Model ◽

Digital Terrain

Covering an area of approximately 97 km2 and with a maximum depth of 58 m, Lake Trichonis is the largest and one of the deepest natural lakes in Greece. As such, it constitutes an important ecosystem and freshwater reserve at the regional scale, whose qualitative and quantitative properties ought to be monitored. Depth is a crucial parameter, as it is involved in both qualitative and quantitative monitoring aspects. Thus, the availability of a bathymetric model and a reliable DTM (Digital Terrain Model) of such an inland water body is imperative for almost any systematic observation scenario or ad hoc measurement endeavor. In this context, the purpose of this study is to produce a DTM from the only official cartographic source of relevant information available (dating back approximately 70 years) and evaluate its performance against new, independent, high-accuracy hydroacoustic recordings. The validation procedure involves the use of echosoundings coupled with GPS, and is followed by the production of a bathymetric model for the assessment of the discrepancies between the DTM and the measurements, along with the relevant morphometric analysis. Both the production and validation of the DTM are conducted in a GIS environment. The results indicate substantial discrepancies between the old DTM and contemporary acoustic data. A significant overall deviation of 3.39 ± 5.26 m in absolute bottom elevation differences and 0.00 ± 7.26 m in relative difference residuals (0.00 ± 2.11 m after 2nd polynomial model corrector surface fit) of the 2019 bathymetric dataset with respect to the ~1950 lake DTM and overall morphometry appear to be associated with a combination of tectonics, subsidence and karstic phenomena in the area. These observations could prove useful for the tectonics, geodynamics and seismicity with respect to the broader Corinth Rift region, as well as for environmental management and technical interventions in and around the lake. This dictates the necessity for new, extensive bathymetric measurements in order to produce an updated DTM of Lake Trichonis, reflecting current conditions and tailored to contemporary accuracy standards and state-of-the-art research in various disciplines in and around the lake.

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