scholarly journals Risks Associated To Present Geomorphologic Processes In The Stemnic (Buda) River Basin

2015 ◽  
Vol 9 (2) ◽  
pp. 181-192
Author(s):  
Ioan Bojoagă

Abstract The paper analyses the main geomorphologic processes in the Stemnic (Buda) river basin, conditioned by the joint action of several factors, among which are the lithological peculiarities and the nature of superficial deposits, morphometric characteristics, climate, vegetation type and structure, properties of the soil cover etc. The Stemnic river basin with an area of 15662.52 ha is characterized by its elongated shape (the maximum length is of 30.5 km, maximum width of 8.5 km), its relative lithological homogeneity, but also by a variety of superficial deposits (eluvium, diluvium, colluvium and proluvium, alluvium) and by a relief energy of significant values between 136 m and 10 m (mean value of 73 m). Under these conditions, study area is characterized by a high degree of susceptibility to the occurrence of geomorphologic risk processes. For the morphometric and morphological analysis, we applied the method of the digital terrain model (DTM) with vectorisation of the contour lines on topographic maps with a scale of 1:5,000. In this paper we used indicators that highlight the particular frequency of landslides, especially in the upper and middle sectors, but the rather reduced frequency of deep erosion. Due to the satisfactory coverage of the ground with vegetation, the erosion reaction is differentiated, as it depends on the use of the land and the concentration of liquid flow on the slopes. Consequently, landslides of different ages, types and forms hold large surfaces in the basin (approx. 8%), while surface erosion affects most areas of the slopes, but with different intensities depending on their use and on agricultural technologies.

2017 ◽  
Vol 38 (1) ◽  
pp. 97
Author(s):  
Gustavo Rodrigues Gimenes ◽  
Rone Batista Oliveira ◽  
Alessandra Fagioli da Silva ◽  
Luiz Carlos Reis ◽  
Teresinha Esteves da Silveira Reis

The slope of terrain represents a risk factor for mechanized harvesting, leading to impediments or restrictions on agricultural operations, or even to machines toppling over in the field. Recently, the Digital Terrain Model (DTM) has become widely adopted as one of the most viable techniques for obtaining slope and elevation. Therefore, this study aims to assess methods of acquiring DTMs to calculate the slope, and to determine the areas that are suitable and unsuitable for the operation of harvesters in the municipality of Bandeirantes (PR). Four methods were selected to produce DTMs for the construction of slope zoning maps applicable for harvester operations. The image sources included SRTM, ASTER GDEM, digitizing contour lines and kriging of spatial point data. After generating DTMs by the four different methods, the area suitable for the operation of harvesters was obtained based on the limits of operational slopes for harvesters in the literature. The high-resolution images, such as those obtained by scanning the contour lines and ASTER GDEM gave the best representation of the ground surface. Regardless of the method used to obtain the operational slopes, the municipality has a large area that is suitable for mechanized harvesting.


Author(s):  
R. Rakesh ◽  
Ashay D Souza ◽  
Sudipta Chattaraj

Watershed characterization is the first step in the sustainable management of    watershed resources. Morphometric analysis of a watershed using Digital Elevation Model (DEM) provides a quantitative description of the drainage system which is an important aspect   of the characterization of watersheds. The study was conducted in Nilona micro-watershed covering an area of 1297.35 ha in Darwha tehsil of Yavatmal district, Maharashtra. The terrain attributes and drainage configuration were derived from the Cartosat-1 data, 10m resolution Digital Terrain Model (DTM) using ArcGIS. Surface soil samples of 118 locations were collected from grid points located at regular interval of 325 m. The digital terrain analysis  showed that slope varies from 0 to 45.9 percent, with a mean value of 4.5%. Most of the area of Nilona micro-watershed was classified as gentle sloping. Profile curvature   varies from -5.1 to 4.6 m m-1, respectively indicating the coexistence of erosive as well  as depositional landforms. Overall, the study documents the utility of   site-specific modeling and geo-statistical interpolation based predictive mapping for watershed planning.


RBRH ◽  
2017 ◽  
Vol 22 (0) ◽  
Author(s):  
Vladimir Fonseca Nascimento ◽  
Alfredo Ribeiro Neto

ABSTRACT This paper reports the application of information acquired by aerial survey to characterize water supply reservoirs in the Pajeú River Basin (Pernambuco State/Brazil). The survey was carried out with digital cameras of high spatial resolution and laser relief profiling (LiDAR technology). Two areas were selected to apply the remote sensing products. Small reservoirs in the Quixaba Creek Basin were identified based on their topographic characteristics. Given that the small reservoirs are “depressions” in the terrain, they can be “filled”, resulting in a new Digital Terrain Model (DTM). The difference between the filled DTM and the original DTM makes it possible to identify the reservoirs. A summary of the results is: 61 reservoirs were correctly detected; 18 reservoirs were not detected; 13 reservoirs were detected erroneously. In another application, the storage capacity of the reservoirs belonging to the hydrosystems of Pajeú River Basin was estimated. The storage in these reservoirs and maximum surface area were estimated using DTM and geoprocessing tools. From the total of 31 reservoirs evaluated, eight were completely empty at the time of the LiDAR data collection. The official registers reported 83.83 million m3 for the storage capacity of these eight reservoirs, whereas our applications estimated the value at 70.23 million m3. This difference is explained by the loss of volume in the reservoirs due to the process of sediment transport.


2019 ◽  
Vol 7 (1) ◽  
pp. 1-20
Author(s):  
Fotis Giagkas ◽  
Petros Patias ◽  
Charalampos Georgiadis

The purpose of this study is the photogrammetric survey of a forested area using unmanned aerial vehicles (UAV), and the estimation of the digital terrain model (DTM) of the area, based on the photogrammetrically produced digital surface model (DSM). Furthermore, through the classification of the height difference between a DSM and a DTM, a vegetation height model is estimated, and a vegetation type map is produced. Finally, the generated DTM was used in a hydrological analysis study to determine its suitability compared to the usage of the DSM. The selected study area was the forest of Seih-Sou (Thessaloniki). The DTM extraction methodology applies classification and filtering of point clouds, and aims to produce a surface model including only terrain points (DTM). The method yielded a DTM that functioned satisfactorily as a basis for the hydrological analysis. Also, by classifying the DSM–DTM difference, a vegetation height model was generated. For the photogrammetric survey, 495 aerial images were used, taken by a UAV from a height of ∼200 m. A total of 44 ground control points were measured with an accuracy of 5 cm. The accuracy of the aerial triangulation was approximately 13 cm. The produced dense point cloud, counted 146 593 725 points.


2019 ◽  
Vol 10 (4) ◽  
pp. 1029-1044
Author(s):  
T. A. Trifonova ◽  
P. S. Shutov

This study was aimed to reveal relationships between the formation of the structures of river systems and to discover the tectonic structural features of the territory. We analyzed the morphometric parameters of river catchment areas of various orders, which comprise the Kama river basin. A digital terrain model in ESRI ArcGis 10.4 geoinformation system was used. Within the identified river basin geosystems, quantitative morphometric characteristics of the terrain were calculated for comparative analysis. Multidimensional statistical analysis methods were used to group the basins with respect to their sets of geometric and morphometric characteristics. A spatial typification technique was developed to distinguish the basin geosystems by their morphometric indicators. This study pioneered in using the results of cluster analysis for identification of seven groups of basins, which reflect the spatial heterogeneity of the ancient tectonic elements and the geomorphological conditions within the entire territory of the Kama river basin. It is established that the types of the river basin geosystems with characteristic morphometric features are related to various ancient tectonic structures, which suggests a genetic relationship of endogenous processes of river channel fracturing and the diversity of geometric parameters of different river basins.


2020 ◽  
Vol 16 (02) ◽  
pp. 31-50
Author(s):  
Angélica Estigarribia São Miguel ◽  
Rafael Brugnolli Medeiros ◽  
Weslen Manari Gomes

A fragilidade ambiental diz respeito à fragilidade do ambiente em função de qualquer tipo de dano causado pela dinâmica ambiental, seja de forma natural e/ou antrópica, sendo relacionada com a erosão do solo e assoreamento dos rios. O objetivo desta pesquisa foi realizar uma análise da fragilidade ambiental da bacia hidrográfica do ribeirão São Pedro, no município de Santa Rita do Pardo/MS, analisando suas características físicas e o uso da terra e cobertura vegetal. Para tanto, a metodologia consiste em duas etapas: a primeira delas na avaliação das precipitações buscando algumas estações meteorológicas no entorno da bacia hidrográfica, trabalhando em ambiente SIG ArcGis 10. A segunda diz respeito ao manuseio das informações sobre áreas prioritárias e solos, buscou-se dados do SISLA/IMASUL, a declividade, trabalhou-se com o modelo digital de terreno SRTM e para o uso da terra e cobertura vegetal a utilização das imagens de satélite Landsat 8. Com isso, a interpolação dessas informações foi embasada na proposta metodológica de Ross (1994) para a fragilidade ambiental. As classes de fragilidade obtidas são a categoria baixa que se mostrou dominante na bacia, sendo presentes em matas nativas e pastagens, a categoria média e alta, que juntas apresentaram 39,56% da área total da bacia foram encontradas em locais com alto declive, concluindo assim que a bacia hidrográfica necessita da análise de suas características, onde qualquer mudança em um de seus elementos pode alterar a fragilidade do local, prejudicando assim, seus recursos naturais. Palavras-chave: Fragilidade ambiental. Sensoriamento Remoto. Uso da terra e cobertura vegetal.   EMPLOYMENT OF REMOTE SENSING AND GEOGRAPHIC INFORMATION SYSTEM IN EVALUATION OF ENVIRONMENTAL FRAGILITY OF HYDROGRAPHIC BASIN SÃO PEDRO, SANTA RITA DO PARDO/MS ABSTRACT The environmental fragility refers to the fragility of the environment due to any kind of damage caused by the environmental dynamics, either naturally or anthropically, and is related to soil erosion and silting of rivers. The objective of this research was to analyze the environmental fragility of the São Pedro river basin, in the municipality of Santa Rita do Pardo / MS, analyzing its physical characteristics and the use of land and vegetation cover. To do so, the methodology consists of two stages: the first one in the evaluation of precipitation by searching for some meteorological stations around the watershed, working in ArcGis 10 GIS environment. The second one concerns the handling of information on priority areas and soils, if data from the SISLA / IMASUL, the slope was worked with the SRTM digital terrain model and for the land use and vegetation cover the use of Landsat 8 satellite images. With this, the interpolation of this information was based on the methodological proposal of Ross (1994) for environmental fragility. The fragility classes obtained are the low category that was dominant in the basin, being present in native forests and pastures, the medium and high category, which together presented 39.56% of the total area of ​​the basin were found in places with high slope, thus concluding that the river basin needs the analysis of its characteristics, where any change in one of its elements can alter the fragility of the place, thus damaging its natural resources. Key Words: Environmental fragility. Remote Sensing. Land use and vegetation cover.   EMPLEO DEL SENSORIAMIENTO REMOTO Y SISTEMA DE INFORMACIÓN GEOGRÁFICA EN LA EVALUACIÓN DE LA FRAGILIDAD AMBIENTAL DE LA BACIA HIDROGRÁFICA DEL RIBEIRÃO SÃO PEDRO, SANTA RITA DO PARDO/MS RESUMEN La fragilidad ambiental se refiere a la fragilidad del ambiente en función de cualquier tipo de daño causado por la dinámica ambiental, sea de forma natural y / o antrópica, estando relacionada con la erosión del suelo y la sedimentación de los ríos. El objetivo de esta investigación fue realizar un análisis de la fragilidad ambiental de la cuenca hidrográfica del río San Pedro, en el municipio de Santa Rita do Pardo / MS, analizando sus características físicas y el uso de la tierra y cobertura vegetal. Para ello, la metodología consiste en dos etapas: la primera de ellas en la evaluación de las precipitaciones buscando algunas estaciones meteorológicas en el entorno de la cuenca hidrográfica, trabajando en ambiente SIG ArcGis 10. La segunda se refiere al manejo de las informaciones sobre áreas prioritarias y suelos, si los datos del SISLA / IMASUL, la declividad, se trabajó con el modelo digital de terreno SRTM y para el uso de la tierra y cobertura vegetal la utilización de las imágenes de satélite Landsat 8. Con ello, la interpolación de esas informaciones se basó en la propuesta metodológica de Ross (1994) para la fragilidad ambiental. Las clases de fragilidad obtenidas son la categoría baja que se mostró dominante en la cuenca, siendo presentes en bosques nativos y pastos, la categoría media y alta, que juntas presentaron el 39,56% del área total de la cuenca se encontraron en locales con alto declive, concluyendo así que la cuenca hidrográfica necesita el análisis de sus características, donde cualquier cambio en uno de sus elementos puede alterar la fragilidad del local, perjudicando así sus recursos naturales. Palabras clave: Fragilidad ambiental. Detección remota. Uso de la tierra y cobertura vegetal.


2009 ◽  
Vol 13 (4) ◽  
pp. 369-375 ◽  
Author(s):  
Samantha A. Alcaraz ◽  
Christophe Sannier ◽  
Antonio C. T. Vitorino ◽  
Omar Daniel

The objective of this work was to compare methodologies for the automatic generation of limits and drainage networks, using a geographical information system for basins of low relief variation, such as the Dourados catchment area. Various data/processes were assessed, especially the ArcHydro and AVSWAT interfaces used to process 50 m resolution DTMs formed from the interpolation of digitalized contour lines using ArcInfo, ArcView and Spring GIS, and a 90 m resolution SRTM DTM acquired by interferometry radar. Their accuracy was estimated based upon the pre-processing of small basic sub-basin units of different relief variations, before applying the best combinations to the entire Dourados basin. The accuracy of the automatic stream network generation and watershed delineation depends essentially on the quality of the raw digital terrain model. The selection of the most suitable one then depends completely on the aims of the user and on the work scale.


2011 ◽  
Vol 17 (1-2) ◽  
Author(s):  
T. Fórián ◽  
A. Nagy ◽  
J. Tamás ◽  
Z. Szabó ◽  
M. Soltész ◽  
...  

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.


2012 ◽  
Vol 212-213 ◽  
pp. 634-640
Author(s):  
Adil I. Hassabo

In this paper, a new semi- automatic method for finding best locations for rain-water drainage lines is developed. The developed method is based on a heuristic greedy algorithm and relies on a digital terrain model (DTM) that can be generated from digitized contour lines or from new remote sensing technologies, such as the airborne laser scanning LiDAR (Light Detection and Ranging) systems. The developed algorithm in this paper uses heuristics and a neighborhood search to find the best locations for rain-water drainage lines between two defined points by minimizing the objective function value by considering a set of constraints, including constrained elevation values and downward slope. The developed algorithm is implemented in a computerized model named (CPline_Route) developed in Microsoft Windows Visual C++6 and was equipped with Graphical User Interface (GUI) to friendly enable users enter their desired parameters and specify an approximate initial line interactively. The performance of the developed computerized tool was tested by restricting a search around a contour line with constrained elevation values, and the result obtained demonstrated that the developed algorithm is effective. It noteworthy that optimal solution cannot be guarantee using greedy heuristic developed in this study. It can be concluded that the developed method is feasible for planning new rain-water drainage lines for new residential areas in developing countries where heavy rains are frequent, and potentially to be useful for planning new pipelines.


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