Meandering River Research Papers - Academia.edu (original) (raw)

- by and +2
- •
- Fluvial Sedimentology, Meandering River

A selection of humorous epitaphs of many mathematicians and physicists of yesteryear

- by David Halprin
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- Parasitology, Newtonian Dynamics, Calculus of Variations, Quantum Mechanics

Braided rivers are relatively simple to produce in the laboratory, whereas dynamic meandering rivers have not been sustained beyond initial bend formation. Meandering is theoretically explained by bend instability growing from planimetric perturbation, which convects downstream. In this study, we experimentally tested the importance of upstream perturbation and chute cutoff development in the evolution and dynamics of a meandering channel pattern. The initial straight channel had a transversely moving upstream inlet point and silt-sized silica flour was added to the sediment feed to allow floodplain formation. We obtained a dynamic meandering river with scroll bars. Bend growth was alternated by chute cutoffs that formed across the point bars. Meandering was maintained as one channel was disconnected by a plug bar. The curvature at the chute bifurcation transported sediment and build a new floodplain, while the other channel widens. At the end of the experiment, the fluvial plain exhibited a meandering channel, point bars, chutes and abandoned and partially filled channels with a slightly cohesive floodplain surface similar to natural meandering gravel-bed rivers. We conclude that the necessary and sufficient conditions for dynamic meandering gravel-bed river are a sustained dynamic upstream perturbation and floodplain formation.

- by Wout van Dijk
- •
- Fluvial Geomorphology, River Morphology, Meandering River, Chute Cutoffs

Braided rivers are relatively simple to produce in the laboratory, whereas dynamic meandering rivers have not been sustained beyond initial bend formation. Meandering is theoretically explained by bend instability growing from planimetric perturbation, which convects downstream. In this study, we experimentally tested the importance of upstream perturbation and chute cutoff development in the evolution and dynamics of a meandering channel pattern. The initial straight channel had a transversely moving upstream inlet point and silt-sized silica flour was added to the sediment feed to allow floodplain formation. We obtained a dynamic meandering river with scroll bars. Bend growth was alternated by chute cutoffs that formed across the point bars. Meandering was maintained as one channel was disconnected by a plug bar. The curvature at the chute bifurcation transported sediment and build a new floodplain, while the other channel widens. At the end of the experiment, the fluvial plain exhibited a meandering channel, point bars, chutes and abandoned and partially filled channels with a slightly cohesive floodplain surface similar to natural meandering gravel bed rivers. We conclude that the necessary and sufficient conditions for dynamic meandering gravel bed river are a sustained dynamic upstream perturbation and floodplain formation.

- by Wout van Dijk and +1
- •
- Hydrology, Combustion, Heat Transfer, Large Eddy Simulation

This research deals with the surface dynamics and key factors –
hydrological regime, sediment load, and erodibility of floodplain
facies – of frequent channel shifting, intensive meandering, and
lateral instability of the Bhagirathi River in the western part of the
Ganga-Brahmaputra Delta (GBD). At present, the floodplain of
the Bhagirathi is categorized as a medium energy (specific stream
power of 10–300 W m−2), non-cohesive floodplain, which exhibits a
mixed-load and a meandering channel, an entrenchment ratio >2.2,
width–depth ratio >12, sinuosity >1.4, and channel slope <0.02. In
the study area, since 1975, four meander cutoffs have been shaped
at an average rate of one in every 9–10 years. In the active meander
belt and sand-silt dominated floodplains of GBD, frequent shifting
of the channel and meander migration escalate severe bank erosion
(e.g. 2.5 × 106 m3 of land lost between 1999 and 2004) throughout the
year. Remote sensing based spatio-temporal analysis and stratigraphic
analysis reveal that the impact of the Farakka barrage, completed in
1975, is not the sole factor of downstream channel oscillation; rather,
hydrogeomorphic instability induced by the Ajay–Mayurakshi fluvial
system and the erodibility of floodplain sediments control the channel
dynamics of the study area.

- by Sandipan Ghosh
- •
- Geography, Physical Geography, Geomorphology, Fluvial Geomorphology
- by Maarten Kleinhans
- •
- Geology, Sediment transport, Meandering River, Particle Size

Field studies suggest that a cohesive floodplain is a necessary condition for meandering in contrast to braided rivers. However, it is only partly understood how the balance between floodplain construction by overbank deposition and removal by bank erosion and chutes leads to meandering. This is needed because only then a dynamic equilibrium exists and channels maintain meandering with low width-depth ratios. Our objective is to understand how different styles of floodplain formation such as overbank deposition and lateral accretion cause narrower channels and prevent chute cutoffs that lead to meandering. In this study we present two experiments with a self-forming channel in identical conditions, but to one we added cohesive silt at the upstream boundary. The effect of cohesive silt on bank stability was tested in auxiliary bank erosion experiments and showed that an increase in silt reduced erosion rates by a factor of 2. The experiment without silt developed to a braided river by continuous and extensive shifting of multiple channels. In contrast, in the meandering river silt deposits increased bank stability of the cohesive floodplain and resulted in a reduction of chute cutoffs and increased sinuosity by continuous lateral migration of a single channel. Overbank flow led to deposition of the silt and two styles of cohesive floodplain were observed; first, overbank vertical-accretion of silt, e.g. levee, overbank sedimentation or splays; and second, lateral point bar accretion with silt on the scrolls and in the swales. The first style led to a reduction in bank erosion, while the second style reduced excavation of chutes. We conclude that sedimentation of fine cohesive material on the floodplain by discharge exceeding bankfull is a necessary condition for meandering.

- by Wout van Dijk
- •
- Fluvial Geomorphology, Fluvial Sedimentology, River Morphology, Meandering River
- by Emre ÖZŞAHİN
- •
- Meandering River, River Meandering

Although fundamental types of fluvial meander-bend transformations – expansion, translation, rotation, and combinations thereof – are widely recognised, the relationship between the migratory behaviour of a meander bend, and its resultant accumulated sedimentary architecture and lithofacies distribution remains relatively poorly understood. Three-dimensional data from both currently active fluvial systems and from ancient preserved successions known from outcrop and subsurface settings are limited. To tackle this problem, a 3D numerical forward stratigraphic model – the Point-Bar Sedimentary Architecture Numerical Deduction (PB-SAND) – has been devised as a tool for the reconstruction and prediction of the complex spatio-temporal migratory evolution of fluvial meanders, their generated bar forms and the associated lithofacies distributions that accumulate as heterogeneous fluvial successions. PB-SAND uses a dominantly geometric modelling approach supplemented by process-based and stochastic model components, and is constrained by quantified sedimentological data derived from modern point bars or ancient successions that represent suitable analogues. The model predicts the internal architecture and geometry of fluvial point-bar elements in three dimensions. The model is applied to predict the sedimentary lithofacies architecture of ancient preserved point-bar and counterpoint bar deposits of the middle Jurassic Scalby Formation (North Yorkshire, UK) to demonstrate the predictive capabilities of PB-SAND in modelling 3D architectures of different types of meander-bend transformations. PB-SAND serves as a practical tool with which to predict heterogeneity in subsurface hydrocarbon reservoirs and water aquifers.

Özet İnsanların suya olan gereksinimlerinden dolayı insanlığın tatlı su kaynakları etrafında yeşermiş olduğu, kültür ve medeniyetin akarsu havzalarında ortaya çıktığı görüşü belirgin bir genellemedir. Bu bağlamda akarsulara çağlar boyu büyük bir önem bazen de kutsiyet atfedilmiştir. Antikçağ yazarları da bu konuya sıkça değinmişler ve akarsuları eserlerine konu etmişlerdir. Pseudo-Plutarkhos da Nehirler Üzerine adlı eserinde ağırlıklı olarak nehirleri konu edinmiş ve nehirler hakkında okuyucuya bazı bilgiler vermeye çalışmıştır. Pseudo-Plutarkhos'un konu edindiği nehirlerden biri de Maiandros (Büyük Menderes Nehri)'tur. Antikçağda Phrygia Bölgesi'ndeki Kelainai yakınlarından kaynağını almış olan Maiandros sözü edilen bölge boyunca akmış daha sonra Lydia, Karia ve Ionia bölgelerinin arazilerini sulayarak Aigaios Pontos'a (Ege Denizi) dökülmüştür. Uzunluğu ve taşıdığı suların bolluğuyla antikçağ Asia'sının (Küçük Asya) en büyük nehri olarak görülmüş, içinden geçtiği coğrafyaları şekillendirmiş ve sağladığı imkanlarla o bölgelere hayat vermiştir. Maiandros Nehri'nin akıntısının zikzaklı olması son derece ilgi çekici olmuş, antikçağ yazarlarının nehre faklı anlamlar yüklemesine ve antikçağ insanının zihninde farklı imgelemler oluşmasına neden olmuştur. Zikzaklar çizen her nehir ya da zikzaklı olan her şey onun adıyla anılmaya başlamıştır. Nehrin akış şeklini esas alan bir bezeme motifi dahi oluşturulmuş ve nehrin adıyla özdeşleştirilmiştir. Bu çalışmada Pseudo-Plutarkhos'un sözü edilen eseri hakkında kısa bir değerlendirme yapıldıktan sonra yazarın anlatılarına istinaden, nehrin isminin kökeninden, akış rotasına, aktığı güzergahtaki yörelere sağladığı yarardan neden olduğu zararlara ve antikçağdan günümüze ulaşan etkilerine değinilmiştir.

This paper is an extension and continuation of an earlier work by the authors on the phenomenon of meandering in Al-Abbasia reach located in the middle of the Euphrates river, Al-Najaf governorate in Iraq. The authors have developed several power functions and models depending on dimensional analysis and Buckingham π-theorem for modeling and predicting the hydraulic geometry of the selected reach. The paper employs the non-linear regression technique for developing mathematical models for computing the width and mean depth of the reach depending on its hydraulic characteristics. This paper is part of an M. Sc. thesis carried out in 2014. The developed relationships are straightforward to be applied in design and analysis with results of high acceptability; the reach width (W) model has an R2 of 0.97, while the reach mean depth (Dm) model has an R2 of 0.93. Different statistical methods have been utilized to compare the different models. The results reveal that non-linear regression ...

- by Mohammed S H A K I R Mahmood
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- Meandering River
- by Filip Schuurman and +1
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- Geology, Geomorphology, Fluvial Processes, Fluvial Geomorphology

Different methods have been used to determine the stratigraphic position of Pleistocene alluvial deposits, particularly fluvial interglacial deposits. Near-surface deposits of a meandering river, developed in point-bar and oxbow lake facies, in the Samica River valley (near £uków, eastern Poland) have been investigated. The fossil valley is incised into the till plain and the outwash. The fluvial succession is locally overlain by solifluction deposits. All the deposits underwent sedimentological analysis. The petrographic composition of basal till occurring in the vicinity of a fossil valley was determined with the method of indicator erratics. Fluvial deposits were examined by pollen analysis and plant macrofossil analysis of oxbow lake facies.
Absolute dating methods were applied to the deposits (thermoluminescence methods: TL and additionally IRSL).
Lithological differences between fluvial and the surrounding glaciofluvial deposits were identified and their lithostratigraphic
position assigned. Petrographic analysis of till and palaeobotanical analyses of oxbow lake facies gave compatible results. Fluvial deposits were formed after the Sanian 2/Elsterian Glaci ation, during the Mazovian/Holsteinian Interglacial. Luminescence dating of the fluvial deposits by the TLMAX method yielded the most relevant results (412–445 ka), which indicate that these deposits were formed during the end of the MIS 12 and beginning of the MIS 11 stage.

- by Tomasz Zieliński and +2
- •
- Glacial Geology, Pleistocene, Chronostratigraphy, Meandering River

In analytical and numerical models of river meandering, initiation of meandering typically occurs uniformly along the streamwise coordinate in the channel. Based on a historical analysis of the Nierskanaal, here we show how and under which circumstances meandering has initiated in isolated sections of a channel. The Nierskanaal was constructed by the end of the 18th century, as a straight channel between the river Niers and the river Meuse. The purpose of this measure was to reduce flood risk in the downstream reaches of the river Niers. The banks on the Dutch part of the channel were left unprotected and developed into a morphodynamically active channel, featuring a meandering planform and valley incision. The planform development and incision process is analysed using topographic maps and airborne LiDAR data. Meandering initiated in three sections of the channel, where the channel sinuosity developed asynchronously. Sedimentary successions in the study area show layers of iron oxide, indicating groundwater seepage from aeolian river dunes and river deposits located nearby. Only at the spots where meandering has initiated iron oxide is found close to the surface level. This provides a clue that seepage triggered bank erosion by increasing moisture content of the banks. The isolated meandering sections expanded in the longitudinal direction. Valley incision has developed in the first decades after the construction of the channel, and diminished after a gravel layer was reached. Gravel was deposited in the downstream half of the channel bed, acting as an armouring layer. The spatial variation in meandering behaviour, as observed in the Nierskanaal, justifies efforts to implement the influence of floodplain heterogeneity and the effect of seepage on bank erosion in meander models. Copyright © 2013 John Wiley & Sons, Ltd.

- by Joris Eekhout and +1
- •
- Historical maps, Fluvial Geomorphology, Meandering River

Stratification in channel belts is the key to reconstructing formative channel dimensions and palaeoflow conditions; this requires an understanding of the relation between river morphodynamics and set thickness. So far, theories for reconstruction of the original morphology from preserved stratification have not been tested for meandering river channels due to the lack of detailed bathymetry. This paper reports the results of an experiment that reproduced a dynamic meandering gravel-bed river with the objectives to: (i) test the prediction of set thickness as a function of the morphology formed by a meandering river channel; and (ii) explore and explain spatial and temporal set thickness variations in the resulting channel belt. High-resolution measurements of time-dependent surface elevation were used to quantitatively relate the preserved stratification to the meandering river morphology. Mean set thickness agrees well with the theoretical prediction from channel morphology. The mean preserved set thickness was 30% of the mean channel depth. Due to the absence of aggradation during the experiment, this provides a lower limit for the preserved mean set thickness which is also to be expected for aggrading systems, because reworking is some orders of magnitude faster than aggradation. Furthermore, the time required to mature a channel belt and its set thickness distribution was about the same as the time required to develop and propagate bends that fill the channel belt surface. Finally, there was much systematic spatial variation in set thickness related to repetitive point bar growth and chute cut-off. Undisturbed and thick sets occurred close to channel belt margins and more irregular stratification with stacked thinner sets was observed in the centre of the channel belt.

- by Wout van Dijk and +1
- •
- Alluvial deposits, Fluvial Sedimentology, Meandering River, River Pattern

Abstract Frequent floods around the globe including recent events in several states in Malaysia have damaged the residential properties, infrastructures and crops or even deaths. Clearing vegetation or trees on the floodplain has been pointed out as a contributing factor to the damages. Thus, the influence of floodplain vegetation on the river hydraulics during flooding must be better understood. The hydraulics of flood flows in non-erodible vegetated meandering channel was experimented in the laboratory where two-lined steel rods were installed along a riparian zone to simulate as trees. The stage-discharge relationship, flow resistance, depth-averaged velocity, streamwise vorticity and boundary shear stress patterns during shallow and deep flood inundations were studied. The findings showed that floodplain vegetation had increased the channel flow depth by 32% and its flow resistance. The velocity in vegetated zone was lowered and the shear stress reduced by 86.5% to 91% along the river meander. In addition, the trees also limit flow interaction between main channel and floodplain. Abstrak Kejadian banjir di seluruh dunia termasuklah di beberapa negeri di Malaysia telah memusnahkan harta benda kediaman, infrastruktur, tanam-tanaman dan juga kehilangan nyawa. Penebangan pokok di dataran banjir telah menyumbangkan kepada tahap kemusnahan tersebut. Oleh itu, adalah penting untuk memahami kesan kehadiran pokok-pokok tersebut terhadap hidraulik sungai ketika banjir. Satu kajian makmal ke atas sistem sungai berliku telah dijalankan. Dua barisan rod besi yang digunakan sebagai pokok-pokok telah disusun di atas dataran banjir di sepanjang sungai. Hubungan aras air-kadaralir, rintangan aliran, corak halaju-halaju primer dan sekunder dan tegasan ricih ketika banjir telah dikaji. Hasil kajian telah menunjukkan bahawa kehadiran pokok-pokok tersebut telah meningkatkan kedalaman aliran sebanyak 32% dan juga rintangan aliran. Halaju aliran telah berkurang dan tegasan ricih jugan menurun di antara 86.5% dan 91%. Pokok-pokok juga telah menghadkan aliran di antara saluran utaman dan dataran banjir. Kata kunci: Permodelan fizikal; eksperimen makmal, saluran berliku, pokok dataran banjir, hidraulik banjir

- by Zulkiflee IBRAHIM and +2
- •
- Meandering River, Flood Hydraulics, Experimental hydraulics

Rivers are significant geomorphic agents which can carry huge amounts of sediments and water from their catchments to depositional basins. Due course of flow they can bring various hazards such as flooding, inundation of flood plains, erosion of banks and trigger various slope movements. To understand nature and behavior of the Bagmati River, which is a perennial, storm and spring-fed, eight order river of central Nepal, the planiform morphological parameters of this river were analysed and river segments along the main stem stretches were classified into various stream-types, using topographic maps, aerial photographs, and satellite imageries. The Bagmati River is an 8th order perennial river. The Bagmati River basin comprises 39 sub-basins of 4th order and higher. The averages of meander wavelengths (Lm), meander belt width (Wblt), radius of curvature (Rc) and sinuosity (K) of the 7th order main stem Bagmati River are 598.27 m, 164.07 m, 252.35 m and 1.38, respectively. Similarly,...

- by Naresh Tamrakar
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- Meandering River

La planicie aluvial del río Portoviejo es parte de un sistema geomorfológico fluvial dinámico que, ha experimentado cambios espaciales en el tiempo y sobre ellos, la acción humana ha sido cada vez más influyente y determinante. Uno de los aspectos necesarios para comprender este complejo esquema evolutivo, además de conocer el comportamiento hidrológico de la cuenca y de sus aspectos geomorfológicos, es el análisis de la dinámica espacio-temporal del canal principal del río en diferentes períodos y, a lo largo de su recorrido en la llanura aluvial, pues ello guarda relación con la movilidad de los escenarios de inundaciones. Los parámetros geométricos del canal principal de un río son muy sensibles a experimentar cambios, como consecuencia de intervenciones antrópicas o de la intensificación de las mismas así, como también, cambios en los patrones de meandros, debido a la carga de sedimentos y a las afectaciones en la geometría del canal. Debido a ello, es propósito de este trabajo, analizar los cambios espacio-temporales de los patrones de meandros del canal principal del río Portoviejo en su planicie aluvial, mediante el análisis de los parámetros morfométricos de sus patrones de meandros. La metodología de trabajo consistió en la revisión y análisis de informes técnicos, imágenes de satélite de Google Earth, cartografía base de la temática existente y observaciones de campo, a partir de las cuales se realizaron fotointerpretaciones de los patrones de meandro y, una matriz de información detallada. Se realizó un muestreo en cada patrón de meandros, para los distintos períodos considerados en el estudio, sobre los cuales se cuantificaron los siguientes parámetros geométricos: longitud del cuello de meandro (L), longitud del eje (A), ancho del meandro del río (W), radio de la curvatura (R), longitud de la curvatura (S) y sinuosidad (C). Los resultados muestran de manera preliminar que, la variabilidad espacio-temporal más significativa de los meandros se observa en el tramo entre las localidades de Colón y Ciudadela Nuevo Portoviejo, correspondiente a áreas con asentamientos poblacionales no planificados y, con intensificación de actividades antrópicas. En este segmento del río se aprecian cambios importantes en la posición de los meandros, determinados por procesos de migración, estrangulamiento o acortamiento, los cuales se expresan considerablemente en la variabilidad de los valores del R. Por el contrario, en el tramo del río, correspondiente al área consolidada de la ciudad de Portoviejo, no se perciben variaciones considerables, lo que define un patrón meandriforme.

This paper is intended to reveal the absurdity of some alleged "progressive" attempts to alter well-tried-and-true beliefs in a deity, to the extent that all they really achieve is an inconsistent kowtowing to overt feminism, assorted... more

- by David Halprin
- •
- Parasitology, Newtonian Dynamics, Philosophy Of Religion, Calculus of Variations
- by Filip Schuurman
- •
- Geology, Geomorphology, Fluvial Processes, Fluvial Geomorphology

Lithological controls increase the range of bend lengths, increase radii of curvatures, simplify bend shapes, increase the distribution of wavelengths, and reduce the length of the dominant wavelength of sinuous rivers. Statistical analyses agree with Stolum (1996) statement that meandering cannot occur in valley widths less than 50 * the channel width (w).

- by James Pizzuto and +1
- •
- Fluvial Geomorphology, Alluvial fans, Meandering River, Bedrock Rivers
- by Adrian Bejan
- •
- Engineering, Mechanical Engineering, Chemical Engineering, Physics
- by Wietse van de Lageweg
- •
- Geology, Fluvial Processes, Fluvial Geomorphology, Meandering River

El río Portoviejo a lo largo de su recorrido ha experimentado una serie de cambios geomorfológicos en sus patrones de meandros, producto de la interrelación entre factores naturales propios de la morfodinámica fluvial de su cuenca, y factores antrópicos prolongados y crecientes en su planicie aluvial. Desde esa perspectiva, en este trabajo se analizan, bajo un enfoque cuantitativo, los procesos geomorfológicos-evolutivos que controlan los cambios espaciales en tres patrones de meandros de la planicie aluvial del río Portoviejo. La metodología desarrollada contempló: (a) análisis estadístico descriptivo para los meandros correspondientes a cada uno de los patrones (segmentos) y según sus parámetros morfométricos; (b) construcción de curvas evolutivas de los meandros de cada segmento en atención a cada parámetro morfométrico; (c) análisis comparativo entre patrones de meandros para cada uno de los años considerados en el período de estudio y por cada parámetro morfométrico; y (d) análisis Biplot Dinámico desarrollado mediante el modelo HJ-Biplot. Los análisis estadísticos fueron desarrollados con los software InfoStat y Rstudio. El análisis estadístico descriptivo reveló que existen amplias diferencias geométricas entre meandros de un mismo segmento, lo que evidencia una movilidad espacio-temporal distinta entre ellos; y entre los segmentos de meandros, indicando un control diferencial de los factores que condicionan la génesis y evolución de cada patrón. Los resultados del Hj-Biplot estático permitieron ver la relación entre los parámetros morfométricos y los meandros por cada segmento o patrón. Se observó que los parámetros R, L y S están correlacionados entre sí, mientras que, las correlaciones negativas entre los parámetros W y C, no son significativas. El análisis dinámico, aparte de exhibir la relación existente entre los parámetros morfométricos, muestra las variaciones de los meandros según esos parámetros a lo largo del período estudiado, observándose que para algunos casos existen variaciones importantes y, para otros, no son muy significativas.

- by Williams José Méndez Mata
- •
- Geomorphology, Ecuador, Fluvial Geomorphology, Geomorfologia Fluvial
- by Janrik van den Berg
- •
- Geology, Sediment transport, Meandering River, Particle Size

Present paper deals with the study of a meander in River Barak around Silchar town in Assam using remote sensing and GIS, encompassing a period of thirty-four years between 1976 and 2010. Changes in planform characteristics of River Barak are analysed with the help of six remote sensing images of the years 1976, 1979, 1988, 1999, 2003, and 2010. The sinuosity of the meander is observed to be quite high (>2.3) exhibiting a decreasing trend in thirty-four years. The meander ratio ranging from 1.05 to 1.12 also exhibited a decreasing trend. The decreasing trends of sinuosity and meander ratio undermine the probability of cut-off across the meander in near future. To analyse the meander shift, three Ground Control Points (GCPs) were selected. It is observed that the western arm of the meander bend around Silchar town has shifted about 132.45 m towards northwest while the eastern arm of the bend has shifted about 61.59 m towards east and 9.88 m towards northwest at two locations respe...

- by Ahmed Fawzi
- •
- Geology, Environmental Impact Assessment, Meandering River, River bank erosion

В статье выявлена взаимосвязь выбросов энергии в пространстве речных излучин со строительством объектов культового назначения (О.К.Н.) на территории Месопотамии и Египта. На примере гидротопографии Древнего Вавилона, его окрестностей (Борсиппа), а также Древнего Египта раскрыта закономерность в месторасположении ряда известных культовых сооружений. По мнению автора, существует прямая зависимость между локализациией О.К.Н. и особенностями местной гидрографии. Кроме того, в работе были произведены расчеты основных
физических параметров импульсного (энергетического) воздействия в речных излучинах / The article reveals the relationship between energy releases in the space of river bends and the construction of religious-purpose
objects within the territory of Mesopotamia and Egypt. By the example of the hydrotopography of Ancient Babylon, its environs
(Borsippa), and also of Ancient Egypt, the study reveals regularity in the location of a number of famous religious buildings.
In the author’s opinion, there is direct relationship between the localization of religious-purpose objects and the features of local
hydrography. In addition, the calculations of the main physical parameters of impulse (energy) effect in river bends are made.

- by Yurchenko Stepan
- •
- Egyptian Archaeology, Energy, Meandering River, Babilonia
- by Wout van Dijk and +1
- •
- Sediment transport and morphodynamics, River Morphology, Meandering River, Floodplains
- by Anna Godlewska and +1
- •
- Geology, Glacial Geology, Pleistocene, Chronostratigraphy

Abstract This research deals with the surface dynamics and key factors – hydrological regime, sediment load, and erodibility of floodplain facies – of frequent channel shifting, intensive meandering, and lateral instability of the Bhagirathi River in the western part of the Ganga-Brahmaputra Delta (GBD). At present, the floodplain of the Bhagirathi is categorized as a medium energy (specific stream power of 10–300 W m−2), non-cohesive floodplain, which exhibits a mixed-load and a meandering channel, an entrenchment ratio >2.2, width–depth ratio >12, sinuosity >1.4, and channel slope <0.02. In the study area, since 1975, four meander cutoffs have been shaped at an average rate of one in every 9–10 years. In the active meander belt and sand-silt dominated floodplains of GBD, frequent shifting of the channel and meander migration escalate severe bank erosion (e.g. 2.5 × 106 m3 of land lost between 1999 and 2004) throughout the year. Remote sensing based spatio-temporal analysis and stratigraphic analysis reveal that the impact of the Farakka barrage, completed in 1975, is not the sole factor of downstream channel oscillation; rather, hydrogeomorphic instability induced by the Ajay–Mayurakshi fluvial system and the erodibility of floodplain sediments control the channel dynamics of the study area.

- by Sandipan Ghosh
- •
- Geography, Physical Geography, Geology, Geomorphology

ABSTRACT Recent studies suggest that braided river could be single-thread channel by colonization of riparian vegetation; however, this kid of mutual interactions between physical and ecological processes in rivers are still poorly understood. Here we investigate the development of meandering channel in a river, which was originally braided and currently vegetated, the Otofuke River in Japan. The significant morphological processes of this river during a destructive flood event was studied using a two-dimensional morphodynamic model. Using well-calibrated parameters, this model qualitatively reproduced observed morphological changes such as the co-development of sand bars, bar-induced meandering and a chute cutoff. We find that for vegetated channels, meandering could maintain moderate sinuosity; in contrast, in the absence of riparian vegetation, bar-induced meandering channels could become braided. This suggests that distinct meandering channels could be a fundamental channel morphology in the originally braided, but currently vegetated river; however, the simultaneous occurrence of the chute cutoff and meandering indicates that this channel could not be a fully-developed high amplitude meandering channel.

- by Yasuyuki Shimizu
- •
- Environmental Engineering, Civil Engineering, Water resources, Meandering River

- by Zaid Hashim
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- Meandering River

Researching the behavior of the river. Especially at the bend, where the morphology of the river is not always straightforward. Flow velocity high water and grinding at river bends occur at different points. This research was conducted on five adjacent bends on the Sidoan River section. This study examined the condition of riverbed sediment, knowing the stability of riverbed sediment granules based on shearing velocity, and stability of riverbed sediment granules based on shear stress. The method used in this study is geometric measurement. Q 50 discharge calculation. produces hydraulic simulation. d 50 sediment diameter. HEC-RAS software simulation and Shields graphs analysis. The results of the study on five bends for Q 50 discharge are the condition of the riverbed in five bends all moving, the critical shear velocity relationship and flow depth are directly proportional, the highest condition at bend 2, otherwise the lowest condition at bend 3. The relationship between particle dimensions and shear velocity is inversely proportional to the value of sliding velocity. if the particle dimensions are small then the large shear stress occurs at bend 5 and vice versa, the dimensions of large particles then the small shear velocity occurs at bend 4, sliding velocity is directly proportional to the shear stress. The highest critical shear stress at bend 2, while the lowest condition at bend 4, the greater the radius of the bend the scouring was deeper.

Rivers is one of the complex natural systems. Classification of the river plan change is very important to know the river problems in early stage, where the classification database can help to understand the behavior of the river in each part. This article discusses about the classification of river plan change at the mainstream of Pahang River, Malaysia. Based on Geographical Information System (GIS) and Remote Sensing (RS) database, analysis of Types Of Lateral Activity (TYLAT) method and Modes of Meander Movement (MOME) method have been used to identify the evolution of the river plan change. The study results indicated, methods of TYLAT are more suitable to use for examining the evolution of river plan change for large and width rivers. While, method of analysis MOME index is more suitable for smaller types of rivers as the upper and middle reaches of the river. From this result, this study can be produced the basic information or database to understanding the characteristics or behavior parts in parts of the main Pahang River. This result also is very important to local authorities to know the early river problems in this area.

- by Azman Azid and +4
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- Remote sensing and GIS applications in Landscape Research, Meandering River, Pahang, Geographic Information Systems (GIS)

Natural rivers are characterized by continuous variations in bed topography, especially along curved reaches. High resolution topographic data are necessary to analyze the mutual
interactions between the downstream flow and the cross-stream flow, which determine the distribution of the bed-shear stress along the channel. Because of the difficulty in acquiring good and
accurate data in rivers, the major part of studies have been conducted in laboratory flumes. This paper reports on a laboratory study in which the automatic digital photogrammetric survey was applied to derive the high-resolution Digital Surface Model (DSM) of the bed topography in a large amplitude meandering flume. In order to assess the advantages of the procedure, the bed profiles obtained by the DSM have been compared with those obtained using a servo-controlled vertical profiler (PV09) has been operated and discussed.

- by donatella termini and +1
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- Close-range Photogrammetry, DSM, Meandering River
- by Eder Merino
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- Meandering River, Pantanal
- by Piotr Czubla
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- Geology, Glacial Geology, Pleistocene, Chronostratigraphy

The Upper Triassic succession in S Poland in which dinosaur bones have been found consists predominantly of siltstones and claystones. Three units are distinguished. The lowermost and the uppermost units reflect an alluvial environment, whereas the middle one represents lacustrine facies. The lower alluvial unit is interpreted as a record of ephemeral, sinuous, suspended-load channels with rapid vertical accretion. Channel barforms are lacking. The environment is interpreted as a low-energy anastomosing fluvial system. The clayey middle unit is interpreted as having formed in a wide long-lived lake. The top of the lacustrine deposits shows signs of vertisol-type pedogenesis, most probably under subtropical conditions, with seasonally-induced wet and dry intervals. The upper unit reflects a low-energy meandering river system. Silty point bars were abundant and the channels migrated freely. The energy level of this fluvial system was slightly higher than that of the earlier one, which...

- by Beata Gruszka
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- Geology, Sedimentology, Sedimentary geology and stratigraphy, Triassic

"On the continuous migrating of meander bends W.M. van Dijk1, W.I. van de Lageweg1, F. Schuurman 1 and M.G. Kleinhans 1 1 Faculty of Geosciences, Department of Physical Geography, Utrecht University, PObox 80115, 3508 TC, Utrecht, The... more

- by Wout van Dijk
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- Hydrology, Sediment transport, Meandering River, Flume Experiments
- by Junya Harpo
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- Software Engineering, Iconoclasm, Intuition, Transactional Leadership