Soil in braided rivers: An overlooked component of braided river morphodynamics

2014 ◽  
pp. 445-452
Author(s):  
N Bätz ◽  
E Verrecchia ◽  
S Lane
Keyword(s):  
Braided River ◽  
Braided Rivers

scholarly journals Sedimentary facies analysis of the fluvial systems in the Siwalik Group, Karnali River section, Nepal Himalaya, and their significance for understanding the paleoclimate and Himalayan tectonics

2016 ◽  
Vol 51 ◽  
pp. 11-26 ◽  
Author(s):  
Ashok Sigdel ◽  
Tetsuya Sakai
Keyword(s):  
River System ◽  
Precipitation Pattern ◽  
Braided River ◽  
River Section ◽  
Meandering River ◽  
Braided Rivers ◽  
Facies Associations ◽  
Siwalik Group ◽  
Himalayan Tectonics ◽  
Flood Flow

Fluvial sediments of the Siwalik successions in the Himalayan Foreland Basin are one of the most important continental archives for the history of Himalayan tectonics and climate change during the Miocene Period. This study reanalyzes the fluvial facies of the Siwalik Group along the Karnali River, where the large paleo-Karnali River system is presumed to have flowed. The reinterpreted fluvial system comprises fine-grained meandering river (FA1), flood-flow dominated meandering river with intermittent appearance of braided rivers (FA2), deep and shallow sandy braided rivers (FA3, FA4) to gravelly braided river (FA5) and finally debris-flow dominated braided river (FA6) facies associations, in ascending order. Previous work identified sandy flood-flow dominated meandering and anastomosed systems, but this study reinterprets these systems as a flood-flow dominated meandering river system with intermittent appearance of braided rivers, and a shallow sandy braided system, respectively. The order of the appearance of fluvial depositional systems in the Karnali River section is similar to those of other Siwalik sections, but the timing of the fluvial facies changes differs. The earlier appearance (3-4 Ma) of the flood-flow dominated meandering river system in the Karnali River section at about 13.5 Ma may have been due to early uplift of the larger catchment size of the paleo-Karnali River which may have changed the precipitation pattern i.e. intensification of the Indian Summer Monsoon. The change from a meandering river system to a braided river system is also recorded 1 to 3 Ma earlier than in other Siwalik sections in Nepal. Differential and diachronous activities of the thrust systems could be linked to change in catchment area as well as diachronous uplift and climate, the combination of which are major probable causes of this diachronity.

scholarly journals Short communication: Challenges and applications of structure-from-motion photogrammetry in a physical model of a braided river

2019 ◽  
Vol 7 (1) ◽  
pp. 97-106 ◽  
Author(s):  
Pauline Leduc ◽  
Sarah Peirce ◽  
Peter Ashmore
Keyword(s):  
Structure From Motion ◽  
Short Communication ◽  
Successful Implementation ◽  
Braided River ◽  
Large Dataset ◽  
Automatic Target Detection ◽  
Braided Rivers ◽  
Digital Elevation ◽  
Communication Challenges ◽  
Close Range

Abstract. For extending the applications of structure-from-motion (SfM) photogrammetry in river flumes, we present the main challenges and methods used to collect a large dataset (>1000 digital elevation models, DEMs) of high-quality topographic data using close-range SfM photogrammetry with a resulting vertical precision of ∼1 mm. Automatic target detection, batch processing, and considerations for image quality were fundamental to the successful implementation of the SfM technique on such a large dataset, which was used primarily for capturing details of gravel-bed braided river morphodynamics and sedimentology. While the applications of close-range SfM photogrammetry are numerous, we include sample results from DEM differencing, which was used to quantify morphology change and provide estimates of water depth in braided rivers, as well as image analysis for mapping bed surface texture. These methods and results contribute to the growing field of SfM applications in geomorphology and close-range experimental settings in general.

Diet of mammalian predators in braided river beds in the central South Island, New Zealand

2004 ◽  
Vol 31 (6) ◽  
pp. 631 ◽  
Author(s):  
Elaine C. Murphy ◽  
Rachel J. Keedwell ◽  
Kerry P. Brown ◽  
Ian Westbrooke
Keyword(s):  
New Zealand ◽  
Bird Species ◽  
Gut Contents ◽  
Frequency Of Occurrence ◽  
Braided River ◽  
Braided Rivers ◽  
Rabbit Haemorrhagic Disease ◽  
Mammalian Predators ◽  
Mustela Furo ◽  
Haemorrhagic Disease

In New Zealand, five of the six endemic bird species that breed primarily in South Island braided river beds are classed as threatened. A major cause of decline for these species is predation by introduced mammals, and predator-trapping programs are undertaken in the braided rivers of the Mackenzie Basin to protect them. Trapping programs carried out between September 1997 and April 2001 provided the opportunity to investigate predator diet from the gut contents of 375 cats (Felis catus), 371 ferrets (Mustela furo) and 86 stoats (Mustela erminea). As a percentage frequency of occurrence of the main prey items, cat diet consisted of lagomorphs (present in 70% of guts), birds (in 47%), lizards (30%) and invertebrates (36%). Ferret diet consisted of lagomorphs (69%) and birds (28%). Stoat diet consisted of lagomorphs (50%), birds (51%), lizards (21%) and invertebrates (23%). The frequency of occurrence of birds in all three predators was higher in the spring/summer of 1997 – immediately after rabbit haemorrhagic disease (RHD) was introduced – than in any other previous diet study on these braided rivers. This suggests that RHD did lead to increased predation pressure on birds, at least in the short term.

scholarly journals Braided-river and hyperconcentrated-flow deposits from the Carboniferous of the Lublin Basin (SE Poland) – a sedimentological study of core data

Geologos ◽  
2012 ◽  
Vol 18 (3) ◽  
pp. 135-161 ◽  
Author(s):  
Maria I. Waksmundzka
Keyword(s):  
Source Area ◽  
High Energy ◽  
Coarse Grained ◽  
Type I ◽  
Braided River ◽  
River Channels ◽  
Fine Grained ◽  
Braided Rivers ◽  
Base Level ◽  
Se Poland

Abstract Fining-upwards cyclothems found in five boreholes in the Carboniferous (Lower Bashkirian) of the Lublin Basin were analysed sedimentologically. It was established that the cyclothems represent fluvial deposits, and the lithofacies were grouped into lithofacies associations. Most lithofacies associations represent three types of sand-bed braided rivers: (1) high-energy, (2) deep and (3) distal sheetflood-affected. Other associations represent hyperconcentrated flows. Both coarse-grained (type I) and fine-grained (types IIa and IIb) occur among the fining-upward cyclothems. The formation of most thick cyclothems was related mainly to allocyclic factors, i.e. a decrease in the river’s gradient. The thickest fining-upward cyclothems are characteristic of hyperconcentrated flows and braided-river channels. The aggradation ratios were commonly high. During the early Namurian C and early Westphalian A (Early Bashkirian), the eastern part of the Lublin Basin was located close to the source area. The sedimentary succession developed due to a transition from high-energy braidedrivers and hyperconcentrated flows to lower-energy braided rivers, controlled by a rise of the regional base level.

scholarly journals Short Communication: Challenges and Applications of Structure-from-Motion Photogrammetry in a Physical Model of a Braided River

2018 ◽  
Author(s):  
Pauline Leduc ◽  
Sarah Peirce ◽  
Peter Ashmore
Keyword(s):  
Structure From Motion ◽  
Short Communication ◽  
Successful Implementation ◽  
Braided River ◽  
Large Dataset ◽  
Automatic Target Detection ◽  
Braided Rivers ◽  
Digital Elevation ◽  
Communication Challenges ◽  
Close Range

Abstract. Extending the applications of Structure-from-Motion (SfM) photogrammetry in river flumes, we present the main challenges and methods used to collect a large dataset (> 1000 digital elevation models) of high-quality topographic data using close-range SfM photogrammetry with a resulting vertical precision of ~ 1 mm. Automatic target-detection, batch processing, and considerations for image quality were fundamental to successful implementation of SfM on such a large dataset, which was used primarily for capturing details of gravel-bed braided river morphodynamics and sedimentology. While the applications of close-range SfM photogrammetry are numerous, we include sample results from DEM differencing, which was used to quantify morphology change and provide estimates of water depth in braided rivers, as well as image analysis for mapping bed surface texture. These methods and results contribute to the growing field of SfM applications in geomorphology and close-range experimental settings in general.

scholarly journals Sedimentation style of a Pleistocene kame terrace from the Western Sudety Mountains, S Poland

Geologos ◽  
2010 ◽  
Vol 16 (2) ◽  
pp. 101-110 ◽  
Author(s):  
Małgorzata Pisarska-Jamroży ◽  
Katarzyna Machowiak ◽  
Dariusz Krzyszkowski
Keyword(s):  
Ice Sheet ◽  
River System ◽  
High Energy ◽  
Braided River ◽  
Braided Rivers ◽  
Mountain Valley ◽  
Sedimentary Succession ◽  
Sudety Mountains ◽  
S Poland ◽  
Lithofacies Association

Sedimentation style of a Pleistocene kame terrace from the Western Sudety Mountains, S PolandThe depositional conditions of kame terraces in a mountain valley were analysed sedimentologically and petrologically through a series of kame terraces in the Rudawy Janowickie mountains. The kame terraces comprise five lithofacies associations. Lithofacies association GRt, Sp originates from deposition in the high-energy, deep gravel-bed channel of a braided river. Lithofacies association GC represents a washed out glacial till. Probably a thin layer of till was washed out by sandy braided rivers (Sp). The fourth association (Fh, Fm) indicates a shallow and quite small glaciomarginal lake. The last association (GRt, GRp) indicates the return of deposition in a sandy-bed braided channel. The petrography of the Janowice Wiekie pit and measurements of cross-stratified beds indicate a palaeocurrent direction from N to S. The Janowice Wielkie sedimentary succession accumulated most probably during the Saalian (Odranian, Saale I, Drenthe) as the first phase of ice-sheet melting, because the kame terrace under study is the highest one, 25-27 m above the Bóbr river level. The deposits under study are dominated by local components. The proglacial streams flowed along the margin of the ice sheet and deposited the kame terrace. The majority of the sedimentary succession was deposited in a confined braided-river system in quite deep channels.

scholarly journals Braided rivers networks dynamics: analyzing topographic data from a large flume experiment

2020 ◽  
Author(s):  
Daniel Papa ◽  
Christophe Ancey
Keyword(s):  
Single Channel ◽  
Quantitative Description ◽  
Stochastic Simulations ◽  
Braided River ◽  
Dimensionless Numbers ◽  
Braided Rivers ◽  
Braided Channel ◽  
Open Questions ◽  
Digital Elevation ◽  
Elevation Model

<p>Braided rivers are highly dynamical systems characterized by varying network-like structures even under quasi-steady conditions. Understanding their dynamics is crucial in geomorphology and river engineering (e.g., river restoration in Alpine and piedmond streams). Open questions about these dynamics include the definition and quantitative description of bed equilibrium. Here we propose to tackle this problem using a new method based on graph theory. This algorithm, called low-path allows one to extract the network structure of a braided river from its Digital Elevation Model (DEM). It is then possible to quantify and analyse the dynamics of the braided system, and not just the bed evolution, as has been done in earlier studies. To assess the dynamics and equilibrium of a braided river, we study two runs representing two distinct phases of the same braided river: the transition from a single channel to a braided river (run 1) and the equilibrium state of this river (run 2). A set of control parameters was used to characterise both runs and supplement the low-path method. We find that although a clear distinction can be made between straight channel and braided channel for both methods, it is more difficult to distinguish between transitional braided and equilibrium braided rivers. Finally we propose a set of dimensionless numbers that specify the braided network and can be used with numerical or stochastic simulations of a braided network. To illustrate their utility, we apply the Low Path method to a real Alpine braided river (the River Navisence, Wallis, Switzerland) and compare the results to our experimental data.</p>

scholarly journals Determining flow directions in river channel networks using planform morphology and topology

2020 ◽  
Vol 8 (1) ◽  
pp. 87-102 ◽  
Author(s):  
Jon Schwenk ◽  
Anastasia Piliouras ◽  
Joel C. Rowland
Keyword(s):  
Flow Direction ◽  
Remotely Sensed ◽  
River Channel ◽  
Braided River ◽  
Channel Network ◽  
Channel Networks ◽  
Braided Rivers ◽  
Morphologic Characteristic ◽  
Network Topologies ◽  
Flow Directions

Abstract. The abundance of global, remotely sensed surface water observations has accelerated efforts toward characterizing and modeling how water moves across the Earth's surface through complex channel networks. In particular, deltas and braided river channel networks may contain thousands of links that route water, sediment, and nutrients across landscapes. In order to model flows through channel networks and characterize network structure, the direction of flow for each link within the network must be known. In this work, we propose a rapid, automatic, and objective method to identify flow directions for all links of a channel network using only remotely sensed imagery and knowledge of the network's inlet and outlet locations. We designed a suite of direction-predicting algorithms (DPAs), each of which exploits a particular morphologic characteristic of the channel network to provide a prediction of a link's flow direction. DPAs were chained together to create “recipes”, or algorithms that set all the flow directions of a channel network. Separate recipes were built for deltas and braided rivers and applied to seven delta and two braided river channel networks. Across all nine channel networks, the recipe-predicted flow directions agreed with expert judgement for 97 % of all tested links, and most disagreements were attributed to unusual channel network topologies that can easily be accounted for by pre-seeding critical links with known flow directions. Our results highlight the (non)universality of process–form relationships across deltas and braided rivers.

scholarly journals Hydraulics of braided river dynamics. Insights from flume experiments

2018 ◽  
Vol 40 ◽  
pp. 02020
Author(s):  
Riccardo Vesipa ◽  
Carlo Camporeale ◽  
Luca Ridolfi
Keyword(s):  
Probability Distribution ◽  
Measurement System ◽  
Water Discharge ◽  
Flowing Water ◽  
Braided River ◽  
Flume Experiments ◽  
Braided Rivers ◽  
Bed Elevation ◽  
Active Channels ◽  
Set Up

We focus on the measurement of the topography and bathymetry in flume-models of braided rivers. To this aim, an innovative measurement system is adopted. It consists of a laser-ultrasonic sensor and can survey the bed elevation under flowing water. This measurement system was used to profile a flume transect with a frequency of 2 minutes, without stopping the water discharge. By this technique, the topography and the bathymetry of a single transect was continuously acquired in 3 braided rivers generated with the same experimental set-up. The main results are: (i) the quantification of the variability of the number of channels and number of active channels; (ii) the assessment of the probability distribution of some key hydraulic and morphodynamic parameters; and (iii) the verification of the repeatability of results obtained from flume-models of braided rivers.

scholarly journals Confluence Dynamics in a Modelled Large Sand-Bed Braided River

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1829
Author(s):  
Haiyan Yang ◽  
Peitong Cong
Keyword(s):  
Laboratory Experiments ◽  
Controlling Factors ◽  
Dynamic Processes ◽  
Suspended Sediment Transport ◽  
Braided River ◽  
Complex Flow ◽  
Field Surveys ◽  
Braided Rivers ◽  
Bed Deformation ◽  
Morphologic Changes

Confluences are key morphological nodes in braided rivers where flow converges, creating complex flow patterns and rapid bed deformation. Field surveys and laboratory experiments have been carried out to investigate the morphodynamic features in individual confluences, but few have investigated the evolution processes of confluences in large braided rivers. In the current study, a physics-based numerical model was applied to simulate a large lowland braided river dominated by suspended sediment transport, and analyze the morphologic changes at confluences and their controlling factors. It was found that the confluences in large braided rivers exhibit some dynamic processes and geometric characteristics that are similar to those observed in individual confluences arising from two tributaries. However, they also show some unique characteristics that may result from the influence of the overall braided pattern and especially of their neighboring upstream channels.

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