scholarly journals A methodology for the preliminary characterisation of the river boundary condition in finite difference groundwater flow numerical models

2019 ◽  
Vol 8 (3) ◽  
Author(s):  
Manuel M. Oliveira ◽  
Tiago N. Martins
Keyword(s):  
Boundary Condition ◽  
Finite Difference ◽  
Numerical Models ◽  
Regional Scale ◽  
River Stage ◽  
Digital Elevation ◽  
Model Cell ◽  
Gis Environment ◽  
Elevation Model

The characterization of the river boundary condition in finite difference numerical models based on MODFLOW requires the quantification of a set of parameters, some of them usually difficult to define. A methodology is presented based on the digital elevation model (DEM) and the river network, to characterize two of these parameters: the stage of the river and the length of the river in each model cell. Suggestions are presented for the other parameters such as the riverbed bottom elevation and the width of the river to be calculated as a function of the river stage, and the riverbed thickness and hydraulic conductivity. The part of the methodology depending on the DEM is explained and demonstrated using a GIS environment with reference to the GIS tools needed to produce the main steps. This methodology produces more representative values of the river stage parameter if at least 9 DEM cells per model cell are used. This methodology allows a first approximation, at a regional scale, for the characterization of the river boundary condition in numerical modelling.

2020 hurricane impact assessment for the northern Gulf of Mexico: Hurricane Sally and Hurricane Zeta

Shore & Beach ◽  
2021 ◽  
pp. 56-64
Author(s):  
S. McGill ◽  
C. Sylvester ◽  
L. Dunkin ◽  
E. Eisemann ◽  
J. Wozencraft
Keyword(s):  
Change Detection ◽  
Gulf Coast ◽  
Regional Scale ◽  
Shoreline Change ◽  
Airborne Lidar ◽  
Digital Elevation ◽  
The Status ◽  
Northern Gulf Coast ◽  
Elevation Model ◽  
Beach Volume

Regional-scale shoreline and beach volume changes are quantified using the Joint Airborne Lidar Bathymetry Technical Center of Expertise’s digital elevation model products in a change detection framework following the passage of the two landfalling hurricanes, Hurricanes Sally and Zeta, along the northern Gulf Coast in late fall 2020. Results derived from this work include elevation change raster products and a standard set of beach volume and shoreline change metrics. The rapid turn-around and delivery of data products to include volume and shoreline change assessments provide valuable information about the status of the coastline and identification of areas of significant erosion or other impacts, such as breaching near Perdido Key, FL, from Hurricane Sally’s impact. These advanced change detection products help inform sediment budget development and support decisions related to regional sediment management and coastal storm risk management.

scholarly journals Compartimentação dos elementos do relevo da bacia hidrográfica do arroio Pantanoso – Canguçu/RS, através da proposta dos geomorphons

2020 ◽  
Vol 13 (2) ◽  
pp. 713
Author(s):  
Danilo Da Silva Dutra ◽  
André Ricardo Furlan ◽  
Luís Eduardo De Souza Robaina
Keyword(s):  
Digital Elevation Model ◽  
River Basin ◽  
Spatial Resolution ◽  
Advantages And Disadvantages ◽  
Digital Elevation ◽  
Relief Elements ◽  
Gis Environment ◽  
Elevation Model

O relevo é a base onde todas as populações vivem e desenvolvem suas atividades, derivando dessa relação vantagens e desvantagens, daí a importância de conhecê-lo através do estudo de suas diferentes formas e elementos. Nesse contexto insere-se a importância de metodologias para o seu estudo, sendo que atualmente vivencia-se a expressividade de dados disponíveis para aplicação de geoprocessamento. A partir das geotecnologias pode-se empreender diversas análises sobre o relevo, destacando-se nesse contexto, a proposta dos geomorphons a qual foi aplicada na bacia hidrográfica do arroio Pantanoso. O objetivo da pesquisa é a identificação e análise dos elementos do relevo definido por geomorphons, quais sejam: 1) Planos, 2) Picos, 3) Cristas, 4) Ressaltos, 5) Crista secundária, 6) Encostas, 7) Escavado, 8) Base de encosta, 9) Vales e 10) Fosso. A determinação dos geomorphons foi a partir do processamento em ambiente SIG do Modelo Digital de Elevação (MDE) do Shuttle Radar Topograph Mission (SRTM) com resolução espacial 3 arcsec (90 metros), “L” Lookup (distância em metros) definiu-se como de 20 pixels (1800 metros) e o “T” Theresholdt (nivelamento em graus) definiu-se em 2º. Para visualização do comportamento dos elementos do relevo na área de estudo realizaram-se trabalhos de campo, o que contribuiu para evidenciar a padronização desses elementos. Os quatro elementos geomorphons mais representativos são encostas, vales, cristas e planos. Subdivision of relief elements through the proposal of geomorphons: river basin of arroio Pantanoso - Canguçu/RS A B S T R A C TRelief is the basis where all populations live and develop their activities, deriving from this relation advantages and disadvantages, hence the importance of knowing it through the study of its different forms and elements. In this context, the importance of methodologies for its study is inserted and geoprocessing application for data available for is currently experienced. From the geotechnologies one can undertake several analyzes on the relief, highlighting in this context, the proposal of the geomorphons which was applied in Pantanoso stream basin. The objective of the research is to identify and analyze the elements of the relief defined by geomorphons, namely: 1) Flats, 2) Peaks, 3) Ridges, 4) Shoulders, 5) Spurs, 6)Slopes, 7) Hollows, 8) Footslope, 9) Valley and 10) Pits. The determination of the geomorphons was based on the GIS environment of the Shuttle Radar Topograph Mission (SRTM) Digital Elevation Model (DEM) with spatial resolution 3 arcsec (90 meters), "L" Lookup (distance in meters) was defined as of 20 pixels (1800 meters) and the "T" Theresholdt (leveling in degrees) was defined in 2º. In order to visualize the behavior of the relief elements in the study area, fieldwork was carried out, which contributed to the standardization of these elements. The four most representative geomorphons, which are: Slopes, Valleys, Ridges and Flat.Keywords: SIG, Geomorphons; Canguçu/RS; relief

scholarly journals The UAS-Based 3D Image Characterization of Mozarabic Church Ruins in Bobastro (Malaga), Spain

2020 ◽  
Vol 12 (15) ◽  
pp. 2377
Author(s):  
Carlos Enríquez ◽  
Juan Manuel Jurado ◽  
Alexandro Bailey ◽  
Danilo Callén ◽  
María José Collado ◽  
...  
Keyword(s):  
3D Reconstruction ◽  
Archaeological Site ◽  
Semantic Classification ◽  
Spatial Features ◽  
Digital Elevation ◽  
Dense Point ◽  
Critical Slope ◽  
Rgb Images ◽  
Elevation Model

In recent years, the application of geomatics tools in archaeology has proved to be very useful to obtain meaningful knowledge of the 3D reconstruction of archaeological remains and semantic classification of the 3D surface. These techniques have proven to be an effective solution for the 3D modeling and the extraction of many spatial features on an archaeological site. However, novel methodologies as well as new data exploitation strategies are required to exploit these geospatial data for natural and cultural heritage documentation, monitoring, and preservation. In this paper, we have studied unique archaeological ruins, a Mozarab church in Al-Andalus, using high-resolution RGB images, which was taken by a drone. Thus, a 3D reconstruction of the ruins and the surrounding environment is carried out in order to characterize it on a dense point cloud. Then, a digital elevation model (DEM) was calculated in order to identify critical slope lines, which are significant to determine where the structure of the church was built. Our results can be used for the development of an architectural project and thus a virtual recreation of these archaeological ruins was performed.

scholarly journals MORPHOMETRIC CHARACTERIZATION OF THE HYDROGRAPHIC BASIN OF JAUQUARA RIVER IN THE TRANSITION BETWEEN THE CERRADO AND AMAZON BIOMES IN MATO GROSSO-BRAZIL

FLORESTA ◽  
2019 ◽  
Vol 49 (2) ◽  
pp. 325
Author(s):  
Gabriel Americo Cassettari ◽  
Tadeu Miranda De Queiroz
Keyword(s):  
Shuttle Radar Topography Mission ◽  
Mato Grosso ◽  
Digital Elevation ◽  
Circularity Index ◽  
Elevation Model ◽  
Basin Area ◽  
Morphometric Characterization ◽  
Effective Water ◽  
Unpublished Information

This study aimed to perform the Jauquara river watershed morphometric characterization. To watershed delimitation was used SRTM 30 type Digital Elevation Model (Shuttle Radar Topography Mission, with spatial resolution of 30 m) provided by USGS Earth Explorer platform. The geographic information system used to watershed delimitation process and maps generation was ArcGIS 10.1 from ESRI®. The morphometric variables calculus was based on classic methodologies of Applied Hydrology. The watershed has an area of 1408,03 km2 and perimeter of 288,43 km with compactness coefficient and circularity index of Kc = 2.15 and Ic = 0.21, respectively, which show an elongated shape. The drainage was classified as 5th order, reinforcing the configuration of the drainage network with a wide hydric distribution. The predominant altitude range is between 368 and 552 m, which corresponds to an area of 478.10 km2. It was observed that there is a predominance of smooth-wavy and undulated reliefs (3-8%, 8-20% slope), which correspond to 38,05% and 23,04% of the total basin area respectively. The morphometric characterization of the basin made it possible to obtain unpublished information that contributes to the decision making regarding the effective water management in the studied area, being this a guiding study for other works

scholarly journals The new remote-sensing-derived Swiss glacier inventory: I. Methods

2002 ◽  
Vol 34 ◽  
pp. 355-361 ◽  
Author(s):  
Frank Paul ◽  
Andreas Kääb ◽  
Max Maisch ◽  
Tobias Kellenberger ◽  
Wilfried Haeberli
Keyword(s):  
Satellite Data ◽  
Accuracy Assessment ◽  
Three Dimensional ◽  
Geographical Information ◽  
Glacier Inventory ◽  
Ratio Image ◽  
Digital Elevation ◽  
First Results ◽  
Gis Environment ◽  
Elevation Model

AbstractA new Swiss glacier inventory is to be compiled from satellite data for the year 2000. The study presented here describes two major tasks: an accuracy assessment of different methods for glacier classification with Landsat Thematic Mapper (TM) data and a digital elevation model (DEM); the geographical information system (GIS)-based methods for automatic extraction of individual glaciers from classified satellite data and the computation of three-dimensional glacier parameters (such as minimum, maximum and median elevation or slope and orientation) by fusion with a DEM. First results obtained by these methods are presented in Part II of this paper (Kääb and others, 2002). Thresholding of a ratio image from TM4 and TM5 reveals the best-suited glacier map. The computation of glacier parameters in a GIS environment is efficient and suitable for worldwide application. The methods developed contribute to the U. S. Geological Survey-led Global Land Ice Measurements from Space (GLIMS) project which is currently compiling a global inventory of land ice masses within the framework of global glacier monitoring (Haeberli and others, 2000).

scholarly journals Flood Impact Assessment Using HEC-RAS and GIS Techniques Dinder River, Southeast Sudan

2021 ◽  
Vol 1 (3) ◽  
pp. 14-19
Keyword(s):  
River Flow ◽  
Flow Behavior ◽  
Normal Height ◽  
Discharge Data ◽  
Four Seasons ◽  
Statistical Computation ◽  
Digital Elevation ◽  
Gis Environment ◽  
Flooded Area ◽  
Elevation Model

Abstract: Dinder River is largest tributary of the Blue Nile. It is seasonal river that flows from June to November and reaches its high peak in September. Frequently, the water level exceeds the normal height causing over bank flow and consequently floods. The floods generally ring about losses properties and crops close to river banks. This study is attempts to figure out the river flow behavior and find out the aerial extent of inundated lands in four flooding seasons. The investigated area is located in Sennar State, SE Sudan. Discharge data collected over the period from 2015 to 2018 and Digital Elevation Model (DEM) have been used to model the River flow regime, while land cover data was used to determine the affected LU/LC types in the area. HEC-RAS software was used to create 2D unsteady flow model in order to simulate Dinder River flooded area in four seasons. The largest flooded area extent in each season was used as input in GIS environment for further spatial analysis. Statistical computation for the affected area and consequent analysis revealed that: the affected urban area in 2018 was around 28.152km2, in 2017 was 29.205 km2, in 2016 was 16.531km2, and in 2015 was 10.422km2. Similar calculations were carried out for the other LU/LC types. According to the present study, the year 2017 witnessed the largest extent of flooding in the area.

Magma system pressurisation and long-term surface deformation at Soufrière Hills Volcano, Montserrat

2021 ◽  
Author(s):  
James Hickey ◽  
Karen Pascal ◽  
Matthew Head ◽  
Jo Gottsmann ◽  
Nico Fournier ◽  
...  
Keyword(s):  
Surface Deformation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Magmatic System ◽  
System Pressure ◽  
Digital Elevation ◽  
Elevation Model ◽  
Magma System ◽  
Continuous Gps

<p>Soufrière Hills Volcano (SHV) is an andesitic dome-building volcano on the island of Montserrat (British West Indies). SHV began its current, and anomalously long, eruption in 1995, but eruptive activity has been intermittent with phases of lava extrusion separated by periods of relative quiescence. The current pause in eruption started in February 2010 and is the longest yet recorded, 10 years and 11 months at the time of writing (January 2021). Continuous GPS measurements show island-wide inflation from 2010 onwards, with the rate of inflation slowly decreasing with time. However, the length of the eruptive pause raises questions as to whether there have been significant changes to the magmatic system and/or the eruption at SHV might have ended. To assess the behaviour and evolution of the SHV magmatic system since 2010 and the relation to ongoing hazard assessment, we analyse the continuous GPS temporal deformation trends using a suite of geodetic numerical models. Our models incorporate a temperature-dependent viscoelastic rheology, topography derived from a Digital Elevation Model and three-dimensional variations in mechanical properties derived from seismic tomography. The models are driven using one of four possible time-dependent source functions, to simulate differences in the temporal evolution of the magmatic system. The results show that the observed deformation data requires a temporal source function whereby the magmatic system pressure is increasing with time. A viscoelastic crustal response cannot explain the long-term deformation trends alone. The nature of the source pressurisation is unclear, and could be due, for example, to one or a combination of, magma supply, degassing/volatile influx, or overturning within a transcrustal magmatic system. Continued pressurisation within the magmatic system highlights the need for sustained vigilance in the monitoring and management of the volcano and its surroundings.</p>

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