scholarly journals Morphometric analysis and prioritization of upper Benue River watershed, Northern Nigeria

2021 ◽  
Vol 11 (2) ◽  
Author(s):  
Caleb Akoji Odiji ◽  
Olaide Monsor Aderoju ◽  
Joseph Bisong Eta ◽  
Idris Shehu ◽  
Adama Mai-Bukar ◽  
...  
Keyword(s):  
Management Strategies ◽  
Decision Makers ◽  
Order System ◽  
Hydrological Process ◽  
Drainage Pattern ◽  
River Watershed ◽  
Digital Elevation ◽  
Hypsometric Integral ◽  
Cumulative Length ◽  
Elevation Model

AbstractThe upper Benue River watershed is undergoing remarkable modifications due to man-made and natural phenomena. Hence, an evaluation is required to understand the hydrological process of the watershed for planning and management strategies. This study aimed to assess the morphometric characteristics and prioritize the upper Benue River watershed. The boundary of the watershed and sub-watersheds, as well as stream networks, was extracted from the digital elevation model (DEM) coupled with hydrological and topographic maps. Twenty-eight morphometric parameters under three categories, i.e. linear, areal, and relief aspects were computed and mapped. Findings from the study revealed that the watershed is a seventh stream order system characterized by a dendritic drainage pattern. The result also showed that 4821 streams were extracted with a cumulative length of 30,232.84 km. The hypsometric integral of the watershed was estimated to be 0.22, indicating that it is in the old stage. In the prioritization of the watershed, the morphometric variables were utilized to calculate and classify the compound factor. The result showed that sub-watersheds 12, 16, 18, 24, 26, and 27 were ranked as very high priority for which conservation measures are required to mitigate the risk of flood and erosion. The outcome of this study can be used by decision-makers for sustainable watershed management and planning.

scholarly journals Conformity of the NASADEM_HGT and ALOS AW3D30 DEM with the Altitude from the Brazilian Geodetic Reference Stations: A Case Study from Brazilian Cerrado

Sensors ◽  
2021 ◽  
Vol 21 (9) ◽  
pp. 2935
Author(s):  
Giovana Maranhão Bettiol ◽  
Manuel Eduardo Ferreira ◽  
Luiz Pacheco Motta ◽  
Édipo Henrique Cremon ◽  
Edson Eyji Sano
Keyword(s):  
Decision Makers ◽  
Surface Model ◽  
Brazilian Cerrado ◽  
Digital Elevation ◽  
Class B ◽  
Crucial Information ◽  
Error Standard Deviation ◽  
Elevation Model ◽  
Main Region

The Brazilian Cerrado (tropical savanna) is the second largest biome in South America and the main region in the country for agricultural production. Altitude is crucial information for decision-makers and planners since it is directly related to temperature that conditions, for example, the climatic risk of rainfed crop plantations. This study analyzes the conformity of two freely available digital elevation models (DEMs), the NASADEM Merged Digital Elevation Model Global 1 arc second (NASADEM_HGT) version 1 and the Advanced Land Observing Satellite Global Digital Surface Model (ALOS AW3D30), version 3.1, with the altitudes provided by 1695 reference stations of the Brazilian Geodetic System. Both models were evaluated based on the parameters recommended in the Brazilian Cartographic Accuracy Standard for Digital Cartographic Products (PEC-PCD), which defines error tolerances according to eight different scales (from 1:1000 to 1:250,000) and classes A (most strict tolerance, for example, 0.17 m for 1:1000 scale), B, C, and D (least strict tolerance, for example, 50 m for 1:250,000 scale). Considering the class A, the NASADEM_HGT meets 1:250,000 and lower scales, while AW3D30 meets 1:100,000 and lower scales; for class B, NASADEM_HGT meets 1:100,000 scale and AW3D30 meets 1:50,000. AW3D30 presented lower values of root mean square error, standard deviation, and bias, indicating that it presents higher accuracy in relation to the NASADEM_HGT. Within eight of Cerrado’s municipalities with the highest grain production, the differences between average altitudes, measured by the Cohen’s effect size, were statistically insignificant. The results obtained by the PEC-PCD for the Cerrado biome indicate that both models can be employed in different DEM-dependent applications over this biome.

scholarly journals MORPHOTECTONICS OF THE PSATHOPYRGOS ACTIVE FAULT, WESTERN CORINTH RIFT, CENTRAL GREECE

2018 ◽  
Vol 40 (1) ◽  
pp. 500 ◽  
Author(s):  
Ch. Tsimi ◽  
A. Ganas ◽  
N. Soulakellis ◽  
O. Kairis ◽  
S. Valmis
Keyword(s):  
Drainage Basin ◽  
Normal Fault ◽  
Normal Faults ◽  
Rift System ◽  
Gulf Of Corinth ◽  
Digital Elevation ◽  
Hypsometric Integral ◽  
Landsat 7 ◽  
Morphotectonic Indices ◽  
Elevation Model

The study area is located on the western part of the Gulf of Corinth which is considered as a paradigm of an active rift system in Greece. This rift was formed by normal slip on big faults which extend the crust of the Earth in the N-S direction. The morphotectonic indices (hypsometric curve, hypsometric integral, drainage basin asymmetry, ratio of valley floor width to valley height) have been estimated using the 20-m digital elevation model of this area and the ARC software. The normal faults of the study area have been extracted by use of a DEM mosaic of 20-m pixel size, satellite images from Landsat 7 ETM+ and SRTM 90m. Our results highlight the recent activity of the Psathopyrgos normal fault on the basis of a series of morphotectonic evidence and suggest the existence of a single fault segment for a distance of 16 km.

scholarly journals Morphotectonic analysis of Kozani Basin (Western Macedonia, Greece)

2017 ◽  
Vol 47 (2) ◽  
pp. 657
Author(s):  
E. Simou ◽  
V. Karagkouni ◽  
G. Papantoniou ◽  
D. Papanikolaou ◽  
P. Nomikou
Keyword(s):  
Large Scale ◽  
Drainage Pattern ◽  
Tectonic Structure ◽  
Tectonic Structures ◽  
River Terraces ◽  
Digital Elevation ◽  
Combined Use ◽  
Digital Modelling ◽  
Elevation Model ◽  
Topographic Relief

Kozani Basin is located in northern-central Greece and constitutes the southernmost of the Plio-Pleistocene basins of western Macedonia. Quantitative and qualitative analysis of morphological slope values, as well as the analysis of the drainage pattern in Kozani Basin confirms that the current topographic relief reflects intense neotectonic activity. Synthetic Morphotectonic Map of the under study area was carried out by means of the combined use of: (a) Digital Elevation Model (DEM), (b) Slope Distribution Map, (c) Morphological Slope Map and (d) Drainage Pattern Map. The composition of the digital modelling in conjunction with the regional geological setting, allows the identification of the main morphological discontinuities and lineaments that result from morphotectonic interpretation. The high morphological slope values indicate well-defined morphotectonic features, which mainly trend NE - SW and, secondarily, NW - SE. Distinct tectonic structures are mostly recognized in the SE margin of Kozani Basin, which is characterized by intense topographic relief. The main large-scale tectonic structure trends NE - SW and corresponds to the major Aliakmonas marginal fault zone that bounds the Kozani basin to the south. On the other hand, the NW margin’s features are indiscernible; thus, the criteria for their recognition are based on the existence of the river terraces, which reflect the tectonic control. The results of our studies are presented on the Morphotectonic Map, which is followed by our 3D model of Kozani Basin.

scholarly journals Constructing a Comprehensive Tool for Deriving Drainage Network using Semi-Open Source Tools and Comparision on Different DEM Data Sources

2014 ◽  
Vol XL-8 ◽  
pp. 1129-1132
Author(s):  
P. K. Gupta ◽  
P. Yadav
Keyword(s):  
Human Error ◽  
Input Parameter ◽  
Data Sources ◽  
Drainage Network ◽  
Drainage Pattern ◽  
Primary Input ◽  
Aster Gdem ◽  
Digital Elevation ◽  
Cartosat Dem ◽  
Elevation Model

Digital elevation model (DEM) provides elevation information in raster format for an area which help in analysis as these phenomena are gravity depended. Hydrological study requires creation of drainage network map. DEM is the primary input for this process. Generally 6 or more processes are required to be completed to get the drainage network. These are available in form of hydrology tools in the ArcGIS software. These processes are manual and time consuming which increases the chances of human error. An automated process is constructed in this paper which aims to create a tool that can handle multiple files in an intelligent manner. <br><br> The input DEM plays a significant role in hydrological studies. This study attempts to do a comparative study to analyse the variation in the drainage network and the intermediate products with the change in the input DEM. <br><br> A tool is created using ArcPy site package in Python programming language to integrate all required hydrology tools. The script is then used to create a tool in ArcGIS 10 which takes location as an input parameter and perform the process on all the DEM files inside the directory. The tool creates separate directory for every DEM file and thus reduces the chances of file mismanagement. The proposed tool is tested on two different datasets namely ASTER GDEM and Cartosat DEM. The tool runs efficiently on both the datasets and thus provides results to compare the drainage pattern produced by these different data sources.

scholarly journals Delineating small karst watersheds based on digital elevation model and eco-hydrogeological principles

2016 ◽  
Author(s):  
G. J. Luo ◽  
S. J. Wang ◽  
X. Y. Bai ◽  
X. M. Liu ◽  
A. Y. Chen
Keyword(s):  
Digital Elevation Model ◽  
River Basin ◽  
Traditional Method ◽  
Yangtze River ◽  
New Method ◽  
Hydrological Process ◽  
Small Watershed ◽  
Small Watersheds ◽  
Digital Elevation ◽  
Elevation Model

Abstract. Dominated by specific eco-hydrogeological backgrounds, a small watershed delineated by using the traditional method is always inauthentic in karst regions because it cannot accurately reflect the eco-hydrological process of the dual structure of the surface and subsurface. This study proposes a new method for the delineation of small watersheds based on digital elevation model (DEM) and eco-hydrogeological principles in karst regions. This method is applied to one section of the tributary area (Sancha River) of the Yangtze River in China. By comparing the quantity, shape, superimposition, and characteristics of the internal hydrological process of a small watershed extracted by using the digital elevation model with that extracted by using the proposed method of this study, we conclude that the s mall karst watersheds extracted by the new method accurately reflect the hydrological process of the river basin. Furthermore, we propose that the minimum unit of the river basin in karst regions should be the watershed whose exit is the corrosion–erosion datum and a further division of watershed may cause a significant inconsistency with the true eco-hydrological process.

scholarly journals A new glacier inventory for the Jostedalsbreen region, Norway, from Landsat TM scenes of 2006 and changes since 1966

2011 ◽  
Vol 52 (59) ◽  
pp. 153-162 ◽  
Author(s):  
Frank Paul ◽  
Liss M. Andreassen ◽  
Solveig H. Winsvold
Keyword(s):  
Field Measurements ◽  
Glacier Inventory ◽  
Digital Elevation ◽  
Cumulative Length ◽  
Length Changes ◽  
Snow Conditions ◽  
The 1960S ◽  
Elevation Model ◽  
Good Agreement ◽  
Area Determination

AbstractPronounced changes in glacier mass and length were observed for the monitored glaciers in the Jostedalsbreen region, Norway, since the last glacier inventories were compiled in the 1960s and 1980s. However, the current overall extent of the glaciers in the region is not well known. To obtain this information, we have compiled a new inventory from two mosaicked Landsat Thematic Mapper (TM) scenes acquired in 2006 that have excellent snow conditions for glacier mapping, the first suitable scenes for this purpose after 22 years of imaging with TM. Drainage divides and topographic inventory parameters were derived from a 25 m national digital elevation model for 1450 glaciers. By digitizing glacier outlines from 1 : 50 000 scale topographic maps of 1966, we calculated changes in glacier area for ~300 glaciers. Cumulative length changes for the 1997–2006 period were derived from an additional TM scene and compared with field measurements for nine glaciers. Overall, we find a 9% area loss since 1966, with a clear dependence on glacier size; however, seasonal snow in 1966 in some regions made area determination challenging. The satellite-derived length changes confirmed the observed high spatial variability and were in good agreement with field data (±1 pixel), apart from glacier tongues in cast shadow. The new inventory will be freely available from the Global Land Ice Measurements from Space (GLIMS) glacier database.

scholarly journals Assessment of Soil Erosion in Siruvani Watersheds Based on USLE and Hypsometric Curve Methods

2019 ◽  
Vol 8 (6S4) ◽  
pp. 1070-1073
Keyword(s):  
Soil Erosion ◽  
Water Conservation ◽  
Drainage Basin ◽  
Entire Study ◽  
Erosion Risk ◽  
Five Factors ◽  
Hypsometric Analysis ◽  
Digital Elevation ◽  
Hypsometric Integral ◽  
Elevation Model

Soil erosion poses a serious threat over the maintenance activities of a reservoir and its watershed. This study has been taken us to assess the extent of soil erosion in the watersheds of the Siruvani Reservoir located in the district of Kerala. Two methods namely, Universal Soil Loss equation (USLE) and Hypsometric curve methods are adapted in this study. Hypsometry of watersheds (area-elevation analysis) has generally been used to reveal the stages of geomorphic development (stabilized, mature and young). The watersheds of Siruvani Reservoir were delineated from the generated Digital Elevation Model (DEM) using Geographic Information System (GIS). Various set of data like land use map, rainfall and soil map have been used for this analysis to generate five factors namely finally, the soil erosion risk map was created to identify the regions which are susceptible to erosion. Hypsometric analysis deals with measurement of the interrelationships between basin area and altitude of basin which has been used to understand the influence of various factors such as climate, geology and tectonic changes. GIS provides advanced tools to obtain hypsometric information and also helps to estimate the associated parameters of landforms. The entire study area has been sub-divided into 5 watersheds for hypsometric analysis and their area ranges from 1.77 to 6.94 km2. The hypsometric curve of the whole the watersheds reflects the mature geomorphic terrain whereas hypsometric integral indicates that the drainage basin has already eroded per cent of land masses. These findings would emphasize the importance of soil and water conservation measures to be taken up in the Siruvani watersheds for controlling further erosion, reducing the sediment outflows and conserve water.

scholarly journals Efficient delineation of nested depression hierarchy in digital elevation models for hydrological analysis using level-set method

2018 ◽  
Author(s):  
Qiusheng Wu ◽  
Charles R. Lane ◽  
Lei Wang ◽  
Melanie K. Vanderhoof ◽  
Jay R. Christensen ◽  
...  
Keyword(s):  
Level Set Method ◽  
Level Set ◽  
Large Scale ◽  
Hydrological Modeling ◽  
Watershed Modeling ◽  
Hydrological Process ◽  
Terrain Analysis ◽  
Digital Elevation ◽  
Elevation Model ◽  
Fine Resolution

In terrain analysis and hydrological modeling, surface depressions (or sinks) in a digital elevation model (DEM) are commonly treated as artifacts and thus filled and removed to create a depressionless DEM. Various algorithms have been developed to identify and fill depressions in DEMs during the past decades. However, few studies have attempted to delineate and quantify the nested hierarchy of actual depressions, which can provide crucial information for characterizing surface hydrologic connectivity and simulating the fill-merge-spill hydrological process. In this paper, we present an innovative and efficient algorithm for delineating and quantifying nested depressions in DEMs using the level-set method based on graph theory. The proposed level-set method emulates water level decreasing from the spill point along the depression boundary to the lowest point at the bottom of a depression. By tracing the dynamic topological changes (i.e., depression splitting/merging) within a compound depression, the level-set method can construct topological graphs and derive geometric properties of the nested depressions. The experimental results of two fine-resolution LiDAR-derived DEMs show that the raster-based level-set algorithm is much more efficient (~150 times faster) than the vector-based contour tree method. The proposed level-set algorithm has great potential for being applied to large-scale ecohydrological analysis and watershed modeling.

scholarly journals Reliability assessment of three topographic methods for generating digital elevation models (DEMs)

2020 ◽  
Vol 12 (2) ◽  
pp. 159-171
Author(s):  
Rodrigo Roblero-Hidalgo ◽  
Jorge Flores-Velázquez ◽  
Jesús Chávez-Morales ◽  
Aurelio Reyes-Ramírez
Keyword(s):  
Management Strategies ◽  
Three Dimensions ◽  
Design Management ◽  
Aerial Photogrammetry ◽  
Contour Lines ◽  
Digital Elevation ◽  
Gps Rtk ◽  
Elevation Model ◽  
Cloud Of Points ◽  
Topographic Surveys

Introduction: A digital elevation model (DEM) allows for the analysis of specific features on the earth’s surface in three dimensions. The engineering DEM is useful to evaluate resources and design management strategies. Objective: To evaluate the technical-operational feasibility of generating DEMs from total station (TS) topographic surveys, GPS RTK and aerial photogrammetry using an unmanned aerial vehicle (UAV). Methodology: A 20x20 m grid was traced in a plot without vegetation (1.4 ha) located in Montecillo, Estado de México, and topographic surveys were carried out with three methods, from which DEMs were generated for graphic and statistical evaluation and by tracing contour lines. Results: The estimated statistical errors were 0.15, 0.15 and 0.02 m, for TS vs. UAV, GPS RTK vs. UAV and TS vs. GPS RTK, respectively. Study limitations: The instruments used and the geographical conditions of central Mexico may be a reason for variation when extrapolating the results with other devices. Originality: A methodology is provided to generate DEMs accurately. The results allow the user to make reasoned choices based on the equipment available. Conclusion: The DEMs generated with TS and GPS RTK data have a smaller error than the one obtained from UAVs. The use of UAV helps in the representation of the terrain, since it generates a dense cloud of points that strengthens the procedure for topographic surveys.

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