Stream Power Determination in GIS: An Index to Evaluate the Most ’Sensitive’Points of a River

This paper focuses on the problem of measuring stream power in a hydrographic network using the original definition provided by Bagnold in 1996. Recent digital elevation models have enabled the calculation of channel gradients and, consequently, stream power with a finer spatial resolution, and this has created promising and novel opportunities to investigate river geomorphological processes and forms. The work carried out in this study includes defining and implementing a methodological approach that could be automated within a geographic information system and that meets two requirements: (1) it uses a DEM as input data at a suitable resolution; (2) it estimates the stream power Ω , as well as its variability along the considered stream, in the best possible way using available data. In particular, the methodological approach was implemented in a GIS environment (GRASS GIS) and applied to a sample basin to highlight the variability in Ω along the main stream and its most important tributaries. The sudden and more substantial variations in stream power were then related to the processes acting in the fluvial system. This approach made it possible to highlight how erosion, solid transport, and sedimentation phenomena occurring along the fluvial reaches are related to abrupt variations (increase/decrease) in the “power” available. The results of this study support the idea that the automated and standardized screening of stream power variability along a stream can be used as a preliminary diagnostic element to identify the most “sensitive” points of the stream on which to concentrate subsequent investigations (field checks to verify the causes), with the aim of mitigating risks due to the dynamics of the riverbed.

Download Full-text

The stream power variation in a GIS environment as an index to evaluate the most 'sensitive' points of a river

10.7287/peerj.preprints.27181v1 ◽

2018 ◽

Author(s):

Pierluigi De Rosa ◽

Corrado Cencetti ◽

Andrea Fredduzzi

Keyword(s):

Methodological Approach ◽

Specific Weight ◽

Main Stream ◽

Stream Power ◽

Time Rate ◽

Liquid Discharge ◽

Digital Elevation ◽

Original Definition ◽

Solid Transport ◽

Gis Environment

The note deals with the problem of measurement and variability, along the fluvial reaches of a hydrographic network, of the stream power, according to the original definition provided by Bagnold (1966) “The available power supply, or time rate of energy supply, to unit lenght of a stream is clearly the time rate of liberation in kinetic form of the liquid’s potential energy as it descends the gravity slope S”. In formula: Ω = ρ g Q S where: Ω = stream power per unit of flow length (W/m) ρ g = density x gravity acceleration = specific weight of the fluid (kg/m3) Q = liquid discharge (m3/s) S = slope of the considered reach (m/m). Recent digital elevation models allow the calculation of channel gradient and consequently stream power with a finer spatial resolution, opening promising and novel opportunities to investigate river geomorphical processes and forms. The work carried out consisted in defining and implementing a methodological approach that could be automated within a geographic information system and that meets two requirements: 1) use input data that is easy to find as DEM at a low resolution; 2) estimate, in the best possible way and on the basis of the available data, the stream power and its variability along the considered stream. In particular, the methodological approach has been implemented in GIS environment (GRASS Gis, Qgis), and it has been applied to a sample basin, highlighting the variability of Ω along the streams of a higher order (in practice the main stream and its most important tributaries). The sudden and more substantial variations of stream power were then related to the processes acting in the fluvial system. This approach has made it possible to highlight how the erosion, solid transport and sedimentation phenomena occurring along the fluvial reaches (and the geomorphological and geologicalapplicative problems that these involve, especially in anthropized areas), are correlated precisely to abrupt variations (increase/decrease) of the ”power” available. Hence the idea that automated and standardized screening of stream power variability along a stream can be used as a preliminary diagnostic element to identify the most ”sensitive” points of the same, on which to concentrate subsequent investigations (field checks, to verify the causes), aimed at mitigating the risk due to the dynamics of the riverbed.

Download Full-text

The stream power variation in a GIS environment as an index to evaluate the most 'sensitive' points of a river

10.7287/peerj.preprints.27181 ◽

2018 ◽

Author(s):

Pierluigi De Rosa ◽

Corrado Cencetti ◽

Andrea Fredduzzi

Keyword(s):

Methodological Approach ◽

Specific Weight ◽

Main Stream ◽

Stream Power ◽

Time Rate ◽

Liquid Discharge ◽

Digital Elevation ◽

Original Definition ◽

Solid Transport ◽

Gis Environment

Download Full-text

Producing a Digital Hydrographic Map Aiming at Renewable Energy Potential Mapping of Lesotho

Journal of Applied Engineering Sciences ◽

10.2478/jaes-2020-00010 ◽

2020 ◽

Vol 10 (1) ◽

pp. 61-68

Author(s):

Francesco Pasanisi ◽

Sergio Grauso ◽

Carlo Tebano ◽

Mabafokeng Mahahabisa ◽

Muso Raliselo

Keyword(s):

Renewable Energy ◽

Satellite Images ◽

Energy Potential ◽

Hydrological Data ◽

Digital Elevation ◽

Catchment Areas ◽

Potential Mapping ◽

Gis Environment ◽

Elevation Model ◽

Hydrographic Network

AbstractSome of the first outcomes of a project aiming at mapping the renewable energy potential in Lesotho are hereby presented. In particular, the present paper deals with the task of the project devoted to produce a digital hydrographic map of Lesotho and an associated geographic database. Different geographical, meteorological and hydrological data were collected in the first steps of the project. The hydrographic network was derived in vector format from a digital elevation model of Lesotho using geoprocessing tools in GIS environment. Results were compared with existing cartography and satellite images. Moreover, a methodology proposed in literature for the assessment of the theoretical maximum hydroelectric producibility at watershed level in Italy was applied to one of the main catchment areas of Lesotho. The activities planned to fulfil the objectives of the project are finally outlined.

Download Full-text

Geomorphometric analysis of cave ceiling channels mapped with 3D terrestrial laser scanning

10.5194/hess-2016-74 ◽

2016 ◽

Cited By ~ 2

Author(s):

Michal Gallay ◽

Zdenko Hochmuth ◽

Ján Kaňuk ◽

Jaroslav Hofierka

Keyword(s):

Laser Scanning ◽

Methodological Approach ◽

Three Dimensional ◽

Terrestrial Laser Scanning ◽

Scalar Fields ◽

Complex Environments ◽

Digital Elevation ◽

Unique Manner ◽

Elevation Model ◽

Different Levels

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organised vertically in different levels. Studying such complex environments traditionally requires tedious mapping, however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterisation and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional scalar fields which is sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a three-dimensional entity therefore a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3D computer graphics which can be applied to study other 3-D geomorphological forms

Download Full-text

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

Revista Brasileira de Geografia Física ◽

10.26848/rbgf.v13.2.p713-726 ◽

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

Download Full-text

Photogrammetric Survey and 3DGIS Management of Mesh in the Integrated Investigation of Complex Sites

Conservation, Restoration, and Analysis of Architectural and Archaeological Heritage - Advances in Religious and Cultural Studies ◽

10.4018/978-1-5225-7555-9.ch003 ◽

2019 ◽

pp. 48-80 ◽

Cited By ~ 2

Author(s):

Ilaria Trizio ◽

Francesca Savini ◽

Romolo Continenza ◽

Alessandro Giannangeli ◽

Alessio Marchetti ◽

...

Keyword(s):

Structure From Motion ◽

Seismic Vulnerability ◽

Methodological Approach ◽

Three Dimensional ◽

Digital Technologies ◽

The State ◽

3D Gis ◽

Archaeological Data ◽

Gis Environment ◽

The University

This chapter illustrates the results of an experimentation carried out by a group of multidisciplinary researchers from the ITC-CNR of L'Aquila and of archaeologists and engineers from the University of L'Aquila. This research project is based on the analysis of architectural and archaeological artefacts (the state of conservation of the artefacts, seismic vulnerability, stratigraphic analysis, construction phases) using methods linked to innovative digital technologies such as digital photogrammetric restitution, based on structure from motion (SfM) algorithms and the generation of photorealistic textures. The innovative methodological approach specifically refers to the management of archaeological data concerning the state of conservation of structures, damages and to their seismic vulnerability in a 3D GIS environment, with particular attention to three-dimensional stratigraphic readings of the artefacts.

Download Full-text

Geomorphometric analysis of cave ceiling channels mapped with 3-D terrestrial laser scanning

Hydrology and Earth System Sciences ◽

10.5194/hess-20-1827-2016 ◽

2016 ◽

Vol 20 (5) ◽

pp. 1827-1849 ◽

Cited By ~ 14

Author(s):

Michal Gallay ◽

Zdenko Hochmuth ◽

Ján Kaňuk ◽

Jaroslav Hofierka

Keyword(s):

Laser Scanning ◽

Methodological Approach ◽

Terrestrial Laser Scanning ◽

Scalar Fields ◽

Complex Environments ◽

New Methods ◽

Digital Elevation ◽

Unique Manner ◽

Elevation Model ◽

Different Levels

Abstract. The change of hydrological conditions during the evolution of caves in carbonate rocks often results in a complex subterranean geomorphology, which comprises specific landforms such as ceiling channels, anastomosing half tubes, or speleothems organized vertically in different levels. Studying such complex environments traditionally requires tedious mapping; however, this is being replaced with terrestrial laser scanning technology. Laser scanning overcomes the problem of reaching high ceilings, providing new options to map underground landscapes with unprecedented level of detail and accuracy. The acquired point cloud can be handled conveniently with dedicated software, but applying traditional geomorphometry to analyse the cave surface is limited. This is because geomorphometry has been focused on parameterization and analysis of surficial terrain. The theoretical and methodological concept has been based on two-dimensional (2-D) scalar fields, which are sufficient for most cases of the surficial terrain. The terrain surface is modelled with a bivariate function of altitude (elevation) and represented by a raster digital elevation model. However, the cave is a 3-D entity; therefore, a different approach is required for geomorphometric analysis. In this paper, we demonstrate the benefits of high-resolution cave mapping and 3-D modelling to better understand the palaeohydrography of the Domica cave in Slovakia. This methodological approach adopted traditional geomorphometric methods in a unique manner and also new methods used in 3-D computer graphics, which can be applied to study other 3-D geomorphological forms.

Download Full-text

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

Annals of Glaciology ◽

10.3189/172756402781817941 ◽

2002 ◽

Vol 34 ◽

pp. 355-361 ◽

Cited By ~ 254

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).

Download Full-text

Google Earth Pro, Panoramio e Youtube como auxílio ao reconhecimento de knickpoints em afluentes dos rios das Velhas e Paraopeba, em Minas Gerais / Google Earth Pro, Panoramio and YouTube as an aid to recognition of the knickpoints in tributaries (...)

Caderno de Geografia ◽

10.5752/p.2318-2962.2018v28n52p226 ◽

2018 ◽

Vol 28 (52) ◽

pp. 226

Author(s):

Renata Jordan Henriques ◽

Roberto Célio Valadão

Keyword(s):

Minas Gerais ◽

Google Earth ◽

A Posteriori ◽

Digital Elevation ◽

Longitudinal Profiles ◽

Fast Flow ◽

Central South ◽

Identification And Characterization ◽

Hydrographic Network

Os elementos constituintes da rede hidrográfica que compõem a superfície terrestre são fundamentais na investigação da morfogênese e morfodinâmica das formas de relevo. Nesse contexto se destacam as rupturas de declividade – os knickpoints – presentes nos perfis longitudinais dos principais afluentes do trecho centro-sul do divisor hidrográfico entre as bacias dos rios das Velhas e Paraopeba, em Minas Gerais. Na investigação desses knickpoints, objeto de análise neste trabalho, foram empregados na identificação da geometria das rupturas por modelos digitais de elevação, imagens orbitais disponibilizadas no Google Earth Pro, fotografias arquivadas no Panoramio e vídeos compartilhados pela plataforma Youtube. Os resultados indicaram rupturas que geram cachoeiras, corredeiras, além de alguns knickpoints utilizados para a construção de barragens. Esse conjunto de recursos se revelou eficiente na identificação e caracterização de knickpoints em canais fluviais, bem como exerceu papel fundamental no planejamento de trabalhos de campo, conduzidos a posteriori.Palavras–chave: geomorfologia fluvial, geotecnologias, perfil longitudinal fluvial.Abstract The elements of the hydrographic network that make up the terrestrial surface are fundamental in the investigation of the morphogenesis and morphodynamics of the relief forms. In this context, the slope ruptures - the knickpoints - present in the longitudinal profiles of the main tributaries of the central-south section of the hydrographic divisor between the Velhas and Paraopeba river basins in Minas Gerais. In the investigation of these knickpoints, object of analysis in this work, were used to identify the geometry of the ruptures by digital elevation models, orbital images available in Google Earth Pro, photographs archived in the Panoramio and videos shared by the Youtube platform. The results indicate ruptures that generate waterfalls, stretches of fast flow, and some knickpoints used for dam construction. This set of resources proved efficient in the identification and characterization of knickpoints in fluvial channels, as well as played a fundamental role in the planning of fieldwork, conducted in the future.Keywords: fluvial geomorphology, geotechnologies, longitudinal river profile.

Download Full-text

REVIEW AND COMPARISON OF WATER EROSION INTENSITY IN THE WESTERN BALKAN AND EU COUNTRIES

Contributions Section of Natural Mathematical and Biotechnical Sciences ◽

10.20903/csnmbs.masa.2015.36.1.63 ◽

2017 ◽

Vol 36 (1) ◽

Author(s):

Ivan Blinkov

Keyword(s):

Methodological Approach ◽

Secondary Data ◽

Water Erosion ◽

European Level ◽

Recent Period ◽

Erosion Risk ◽

Balkan Countries ◽

Gis Environment ◽

National Databases ◽

Erosion Intensity

The south and southeast region of Europe is significantly prone to water erosion. In parts of the region, erosion has reached a stage of irreversibility and in some places erosion has practically ceased because there is no soil left. In the recent period several models and approaches in a GIS environment were developed using available database for erosion factors on the European level on which data about water erosion in Western Balkan countries is missing. Sci-entists in the Western Balkan countries faced with the erosion problem for years, developed own models or prepared various erosion risk maps using national databases. The aim of this study is to compare results of water erosion inten-sity in the Western Balkan countries using models on wider level (European maps) and national researches. The basic methodological approach in this paper is an analysis of secondary data, using the method of "content analysis" of various data sources. Inductive and deductive qualitative analyses were used and finally the method of "comparative analysis" is applied, too. Through the analysis of national researches it was estimated that erosion intensity in the WB countries is 656 m3/ha (similar to 6.56 t/ha) and the total amount of annual produced erosive material is 373.8·106 m3. The most erosive countries in Europe are Albania and Montenegro where mean annual intensity of erosion is > 10 t/ha. Macedonia together with Italy, Portugal, Slovenia and Romania is in the second group of countries, where ero-sion intensity is 5–10 t/ha.

Download Full-text