scholarly journals ANALYSIS OF MORPHOLOGICAL AND HYDROLOGICAL CHANGES IN THE CORRENTES RIVER

GEOGRAFIA ◽  
2018 ◽  
Vol 42 (3) ◽  
pp. 9-25
Author(s):  
Edson Rodrigo dos Santos da SILVA ◽  
Aguinaldo SILVA ◽  
Beatriz Lima de Paula SILVA ◽  
Luciana Escalante PEREIRA ◽  
Edward Limin LO ◽  
...  
Keyword(s):  
Morphological Changes ◽  
Rapid Change ◽  
Field Work ◽  
Temporal Analysis ◽  
Downstream Migration ◽  
Meandering Rivers ◽  
Channel Adjustment ◽  
Landuse Planning ◽  
Hydroelectric Dam ◽  
Rectilinear Channel

Meandering rivers have a number of features that differentiate them from rectilinear and anastomosing channels, such as the rapid change of course, which is the result of continuous adjustments of hydro-sedimentary factors. Studying these changes helps to inform on the potential future changes, and generates valuable data for landuse planning. This study aims to identify the morphological changes in the lower Correntes River between 1984 and 2016, and generate information that is currently scarce about the watershed. A temporal analysis of migrating meanders using remote sensing, literature search, and field work was conducted. This river is highly mobile with lateral and downstream migration, exhibiting a rectilinear channel tendency as shown by the decreased sinuosity between 1984 and 2016. This trend reflects channel adjustment in relation to hydro-sedimentary factors. Because the upstream hydroelectric dam retained sediment and enhanced flow velocity, erosion and meander migration increased. In addition to the channel modification, the dam caused observable changes to the river stage and discharge

scholarly journals MODELLING LANDSCAPE MORPHODYNAMICS BY TERRESTRIAL PHOTOGRAMMETRY: AN APPLICATION TO BEACH AND FLUVIAL SYSTEMS

2016 ◽  
Vol XLI-B8 ◽  
pp. 1175-1182 ◽  
Author(s):  
E. Sánchez-García ◽  
A. Balaguer-Beser ◽  
R. Taborda ◽  
J. E. Pardo-Pascual
Keyword(s):  
Morphological Changes ◽  
Spatial Scales ◽  
Cost Effective ◽  
Point Clouds ◽  
Field Work ◽  
Fluvial Systems ◽  
Natural Systems ◽  
3D Point Clouds ◽  
Pilot Channel ◽  
Terrestrial Photogrammetry

Beach and fluvial systems are highly dynamic environments, being constantly modified by the action of different natural and anthropic phenomena. To understand their behaviour and to support a sustainable management of these fragile environments, it is very important to have access to cost-effective tools. These methods should be supported on cutting-edge technologies that allow monitoring the dynamics of the natural systems with high periodicity and repeatability at different temporal and spatial scales instead the tedious and expensive field-work that has been carried out up to date. The work herein presented analyses the potential of terrestrial photogrammetry to describe beach morphology. Data processing and generation of high resolution 3D point clouds and derived DEMs is supported by the commercial Agisoft PhotoScan. Model validation is done by comparison of the differences in the elevation among the photogrammetric point cloud and the GPS data along different beach profiles. Results obtained denote the potential that the photogrammetry 3D modelling has to monitor morphological changes and natural events getting differences between 6 and 25 cm. Furthermore, the usefulness of these techniques to control the layout of a fluvial system is tested by the performance of some modeling essays in a hydraulic pilot channel.

scholarly journals Long-term hydrological changes after various river regulation measures: are we responsible for flow extremes?

2019 ◽  
Vol 50 (2) ◽  
pp. 417-430 ◽  
Author(s):  
Tímea Kiss ◽  
Károly Fiala ◽  
György Sipos ◽  
Gábor Szatmári
Keyword(s):  
Human Impacts ◽  
Morphological Changes ◽  
River Regulation ◽  
Mass Movements ◽  
Channel Adjustment ◽  
Flood Level ◽  
Flow Changes ◽  
Tisza River ◽  
Natural Channel

Abstract Engineering works have affected the morphology of rivers (e.g., by cut-offs, artificial levees, revetments, and reservoir and dam constructions). These human impacts also have hydrological impacts, as they alter the natural channel geometry, affect the carrying capacity of the channel and confine the floodplains. The goals of the present paper are to analyse flow changes for the Tisza River (in Hungary) with its highly regulated channel using a long (141 y) daily hydrologic dataset and to evaluate the engineering works from the point of hydrological and morphological equilibrium. Since the late 19th century, the flood level along the Lower Tisza River has increased by 216 cm; further, since 1998, flood levels increased by over 80 cm without an increase in discharge. In addition, river stages for low flows have decreased, and the water slope has decreased. These changes are likely connected to morphological changes in the channel (e.g., incision, narrowing, disappearance of point bars, intensifying mass movements), which have been driven by the complex response to human impacts. While the channel could adjust itself to convey larger floods after the cut-offs, the revetments impede the channel adjustment and contribute to the hydrological and morphological disequilibrium state along the Tisza River.

There-dimensional change detection in coastal cliffs using UAV and TLS

2020 ◽  
Author(s):  
Yuichi S. Hayakawa ◽  
Hiroyuki Obanawa
Keyword(s):  
Point Cloud ◽  
Morphological Changes ◽  
Three Dimensional ◽  
Dimensional Change ◽  
Point Clouds ◽  
Temporal Analysis ◽  
Small Island ◽  
Cloud Data ◽  
Tidal Waves ◽  
Coastal Cliffs

<p>Measuring three-dimensional morphological changes in rocky coasts is essential in protecting the </p><p>coastal areas and evaluating the sediment dynamics therein. In this study, we carried out repeated </p><p>measurements of the three-dimensional morphology of a small rocky island using terrestrial laser </p><p>scanning (TLS) and unmanned aerial vehicle (UAV)-based structure-from-motion (SfM) </p><p>photogrammetry for 5 years. The TLS-derived point cloud data is used to align the UAV-SfM point </p><p>cloud with a better accuracy at a centimeters scale, for which iterative closest point (ICP) method was </p><p>applied. Aligned UAV-derived point clouds were then compared each other to extract changed mass </p><p>for each time period. The extracted point cloud of changed mass was converted to 3D mesh polygons, </p><p>by which the total volume of eroded mass was calculated.</p><p>The temporal analysis of the point cloud revealed spatially variable rockfalls and wave cuts. The </p><p>eroded mass volume for each period varied from 10.6 to 527.7 m3, which is equivalent to the horizontal </p><p>erosion rates of 0.03 to 0.63 m/y. The temporal changes in the eroded volume is roughly associated </p><p>with that in the frequency of high tidal waves (higher than 3 m) observed in this area. However, less </p><p>correlation was found with the frequency of large ground shakes by earthquakes. The modern erosion </p><p>rate is lower than the previously reported cliff retreat rates, but this suggests that the small island will </p><p>disappear in decades. Three-dimensional structural analysis will also help understand the dynamic </p><p>processes of the erosion of the bedrock cliffs in the island.</p>

Publishing in the round: a role for CD-ROM in the publication of archaeological field-work results

Antiquity ◽  
1997 ◽  
Vol 71 (274) ◽  
pp. 1062-1066 ◽  
Author(s):  
Dominic Powlesland
Keyword(s):  
Rapid Change ◽  
Field Work ◽  
Compact Disk ◽  
Cd Rom ◽  
Read Only Memory ◽  
Available Technology

Some five months have elapsed since I was invited to write this paper and, as seems always to be the case, the continued rapid change in applied computing and available technology has transformed my view of the potentials offered by CD-ROM (Compact Disk-Read Only Memory) as a publishing medium. The paper I now offer is substantially different in content; the conclusions, however, are the same.

scholarly journals UAV Photogrammetry and Ground Surveys as a Mapping Tool for Quickly Monitoring Shoreline and Beach Changes

2020 ◽  
Vol 8 (1) ◽  
pp. 52 ◽  
Author(s):  
Antonio Zanutta ◽  
Alessandro Lambertini ◽  
Luca Vittuari
Keyword(s):  
Morphological Changes ◽  
Three Dimensional ◽  
Temporal Analysis ◽  
Anthropogenic Factors ◽  
Engineering Structures ◽  
Northern Adriatic ◽  
Mapping Tool ◽  
Multi Temporal ◽  
Maintenance Work ◽  
Three Dimensional Models

The aim of this work is to evaluate UAV photogrammetric and GNSS techniques to investigate coastal zone morphological changes due to both natural and anthropogenic factors. Monitoring morphological beach change and coastline evolution trends is necessary to plan efficient maintenance work, sand refill and engineering structures to avoid coastal drift. The test area is located on the Northern Adriatic coast, a few kilometres from Ravenna (Italy). Three multi-temporal UAV surveys were performed using UAVs supported by GCPs, and Post Processed Kinematic (PPK) surveys were carried out to produce three-dimensional models to be used for comparison and validation. The statistical method based on Crossover Error Analysis was used to assess the empirical accuracy of the PPK surveys. GNSS surveys were then adopted to evaluate the accuracy of the 2019 photogrammetric DTMs. A multi-temporal analysis was carried out by gathering LiDAR dataset (2013) provided by the “Ministero dell’Ambiente e della Tutela del Territorio e del Mare” (MATTM), 1:5000 Regional Technical Cartography (CTR, 1998; DBTR 2013), and 1:5000 AGEA orthophotos (2008, 2011). The digitization of shoreline position on multi-temporal orthophotos and maps, together with DTM comparison, permitted historical coastal changes to be highlighted.

scholarly journals Morphological Changes Detection of a Large Earthflow Using Archived Images, LiDAR-Derived DTM, and UAV-Based Remote Sensing

2020 ◽  
Vol 13 (1) ◽  
pp. 120
Author(s):  
Massimo Conforti ◽  
Michele Mercuri ◽  
Luigi Borrelli
Keyword(s):  
Morphological Changes ◽  
Source Area ◽  
Temporal Analysis ◽  
Earth Satellite ◽  
Google Earth ◽  
Aerial Photographs ◽  
Temporal Data ◽  
Transport Zone ◽  
Multi Temporal ◽  
System Data

In mountainous landscapes, where strongly deformed pelitic sediments outcrop, earthflows can dominate denudation processes and landscape evolution. This paper investigated geological and geomorphological features and space-time evolution over a 65-year time span (1954–2019) of a large earthflow, representative of wide sectors of the Apennine chain of southern Italy. The landslide, with a maximum length of 1.85 × 103 m, affects an area of 4.21 × 105 m2 and exhibits two source zones: a narrow and elongated transport zone and a lobate accumulation zone. Spatial and temporal morphological changes of the earthflow were assessed, comparing multi-source and multi-temporal data (aerial photographs, Google Earth satellite images, Light Detection and Ranging (LiDAR) and Unmanned Aerial Vehicles (UAV) system data). Geomorphic changes, quantified using Digital Terrain Models (DTMs) of differences, highlighted an extensive lowering of the topographic surface in the source area and a significant uplift at the landslide toe. Moreover, the multi-temporal analysis showed a high increase of landslide surface (more than 66%) during the last 65 years. The volumetric analyses showed that different sectors of the earthflow were active at different times, with different rates of topographic change. Overall, the used approach highlighted the great potentiality of the integration of multi-source and multi-temporal data for the diachronic reconstruction of morphological landslide evolution.

scholarly journals MODELLING LANDSCAPE MORPHODYNAMICS BY TERRESTRIAL PHOTOGRAMMETRY: AN APPLICATION TO BEACH AND FLUVIAL SYSTEMS

2016 ◽  
Vol XLI-B8 ◽  
pp. 1175-1182
Author(s):  
E. Sánchez-García ◽  
A. Balaguer-Beser ◽  
R. Taborda ◽  
J. E. Pardo-Pascual
Keyword(s):  
Morphological Changes ◽  
Spatial Scales ◽  
Cost Effective ◽  
Point Clouds ◽  
Field Work ◽  
Fluvial Systems ◽  
Natural Systems ◽  
3D Point Clouds ◽  
Pilot Channel ◽  
Terrestrial Photogrammetry

Beach and fluvial systems are highly dynamic environments, being constantly modified by the action of different natural and anthropic phenomena. To understand their behaviour and to support a sustainable management of these fragile environments, it is very important to have access to cost-effective tools. These methods should be supported on cutting-edge technologies that allow monitoring the dynamics of the natural systems with high periodicity and repeatability at different temporal and spatial scales instead the tedious and expensive field-work that has been carried out up to date. The work herein presented analyses the potential of terrestrial photogrammetry to describe beach morphology. Data processing and generation of high resolution 3D point clouds and derived DEMs is supported by the commercial Agisoft PhotoScan. Model validation is done by comparison of the differences in the elevation among the photogrammetric point cloud and the GPS data along different beach profiles. Results obtained denote the potential that the photogrammetry 3D modelling has to monitor morphological changes and natural events getting differences between 6 and 25 cm. Furthermore, the usefulness of these techniques to control the layout of a fluvial system is tested by the performance of some modeling essays in a hydraulic pilot channel.

scholarly journals DYNAMIC MORPHOLOGICAL CHANGES OF SPIT IN APRIL–MAY 2014 IN OPAK RIVER MOUTH, BANTUL, DAERAH ISTIMEWA YOGYAKARTA

2015 ◽  
Vol 6 (2) ◽  
Author(s):  
Yan Restu Freski ◽  
Agung Setianto ◽  
Srijono Srijono
Keyword(s):  
Global Positioning System ◽  
Wind Direction ◽  
Morphological Changes ◽  
River Mouth ◽  
Field Work ◽  
Google Earth ◽  
Aerial Photographs ◽  
Ocean Energy ◽  
Global Positioning ◽  
Periodic Models

As an oceanic coast, the beaches in the southern part of Java Island are predominantly influenced by ocean energy which is driven by periodical monsoon. This periodical process impacts the dynamic changes of spit in the river mouth system. Therefore, spit is a key to study the process in the southern coast of Java Island especially in Opak River Mouth. It needs a deep-root explanation about the morphological changes and the sedimentological mechanism. This research project was built by data such as spit geometry, aerial photographs and spontaneous wind direction. The supporting data included multitemporal IKONOS-Quickbird images from Google Earth and aerial photographs. These data were collected from field-work investigation and laboratorywork. The spit geometry was compiled by Global Positioning System handheld tracking along the edge of spit and crosschecked by aerial photograph using pole. The ultimate interpretation and periodic models were built by data reconstruction based on the geometry of spit and spontaneous wind direction. Spit changed weekly due to monsoon transition in April to May 2014. The morphological changes could be noted as the spit starting to be cut off by the highrate flow of Opak River. The process continued until the net drift moving westward. Keywords: April, coast, May, Opak river mouth, spit.

scholarly journals UAV-based evaluation of morphological changes induced by extreme rainfall events in meandering rivers

PLoS ONE ◽  
2020 ◽  
Vol 15 (11) ◽  
pp. e0241293
Author(s):  
Semih Sami Akay ◽  
Orkan Özcan ◽  
Füsun Balık Şanlı ◽  
Tolga Görüm ◽  
Ömer Lütfi Şen ◽  
...  
Keyword(s):  
Water Level ◽  
Extreme Precipitation ◽  
Morphological Changes ◽  
Extreme Rainfall ◽  
Precipitation Event ◽  
River Channels ◽  
Meandering Rivers ◽  
Erosion And Deposition ◽  
Extreme Rainfall Events ◽  
Rainfall Events

Morphological changes, caused by the erosion and deposition processes due to water discharge and sediment flux occur, in the banks along the river channels and in the estuaries. Flow rate is one of the most important factors that can change river morphology. The geometric shapes of the meanders and the river flow parameters are crucial components in the areas where erosion or deposition occurs in the meandering rivers. Extreme precipitation triggers erosion on the slopes, which causes significant morphological changes in large areas during and after the event. The flow and sediment amount observed in a river basin with extreme precipitation increases and exceeds the long-term average value. Hereby, erosion severity can be determined by performing spatial analyses on remotely sensed imagery acquired before and after an extreme precipitation event. Changes of erosion and deposition along the river channels and overspill channels can be examined by comparing multi-temporal Unmanned Aerial Vehicle (UAV) based Digital Surface Model (DSM) data. In this study, morphological changes in the Büyük Menderes River located in the western Turkey, were monitored with pre-flood (June 2018), during flood (January 2019), and post-flood (September 2019) UAV surveys, and the spatial and volumetric changes of eroded/deposited sediment were quantified. For this purpose, the DSAS (Digital Shoreline Analysis System) method and the DEM of Difference (DoD) method were used to determine the changes on the riverbank and to compare the periodic volumetric morphological changes. Hereby, Structure from Motion (SfM) photogrammetry technique was exploited to a low-cost UAV derived imagery to achieve riverbank, areal and volumetric changes following the extreme rainfall events extracted from the time series of Tropical Rainfall Measuring Mission (TRMM) satellite data. The change analyses were performed to figure out the periodic morphodynamic variations and the impact of the flood on the selected meandering structures. In conclusion, although the river water level increased by 0.4–5.9 meters with the flood occurred in January 2019, the sediment deposition areas reformed after the flood event, as the water level decreased. Two-year monitoring revealed that the sinuosity index (SI) values changed during the flood approached the pre-flood values over time. Moreover, it was observed that the amount of the deposited sediments in September 2019 approached that of June 2018.

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