scholarly journals Biogeochemistry of the Amazonian Floodplains: Insights from Six End-Member Mixing Models*

2010 ◽  
Vol 14 (9) ◽  
pp. 1-83 ◽  
Author(s):  
Vincent Bustillo ◽  
Reynaldo Luiz Victoria ◽  
Jose Mauro Sousa de Moura ◽  
Daniel de Castro Victoria ◽  
Andre Marcondes Andrade Toledo ◽  
...  
Keyword(s):  
Water Storage ◽  
Relevant Information ◽  
Main Channel ◽  
Mixing Models ◽  
Flood Wave ◽  
River Water Chemistry ◽  
Tight Connection ◽  
Submerged Area ◽  
River Corridors ◽  
Main Factor

Abstract The influence of Amazonian floodplains on the hydrological, sedimentary, and biogeochemical river budget was investigated along the Vargem Grande–Óbidos reach, by applying six mixing models based on variable regional and/or variable hydrological sources. By comparing the output of many different models designed for different purposes, the nature and the magnitude of processes linking water and biogeochemical budgets of the Amazonian floodplains were clarified. This study reveals that most of the chemical baseline of the Amazon River basin is acquired before the studied 2000-km Amazonian reach. However, the tight connection between the hydrograph stage of the river and the chemical signals provides insightful information on the dynamics of its floodplains. The chemical expression of biotic and abiotic processes occurring in the Amazonian floodplains can be particularly perceived during falling waters. It appears delayed in time compared to the maximum extension of submerged area, because the alternating water circulation polarity (filling versus emptying) between the main channel and the adjacent floodplains determines delayed emptying of floodplains during falling waters. It results also in a longer time of residence in the hydrograph network, which strengthens the rate of transformation of transiting materials and solutes. Biotic and biologically mediated processes tend to accentuate changes in river water chemistry initiated upstream, in each subbasin, along river corridors, indicating that processes operating downstream prolong those from upstream (e.g., floodplains of the large tributaries). Conversely, the flood wave propagation tends to lessen the seasonal variability as a result of the water storage in the floodplains, which admixes waters of distinct origins (in time and space). The morphology of floodplains, determining the deposition and the diagenesis of the sediments as well as the variable extension of submerged areas or the chronology of floodplains storage/emptying, appears to be the main factor controlling the floodplains biogeodynamics. By coupling classical end-member mixing models (providing insight on hydrological source) with a variable regional contribution scheme, relevant information on the biogeochemical budget of the Amazonian floodplains can be achieved.

Morphological effects of a hydraulic lifting dam on the middle Fenhe River, China

2021 ◽  
Author(s):  
Yufang Ni ◽  
Zhixian Cao ◽  
Wenjun Qi ◽  
Xiangbin Chai ◽  
Aili Zhao
Keyword(s):  
Shallow Water ◽  
General Pattern ◽  
Water Storage ◽  
Main Channel ◽  
Environmental Restoration ◽  
Two Dimensional ◽  
Compound Channel ◽  
Computationally Efficient ◽  
Bed Deformation ◽  
Numerical Predictions

<p>Hydraulic lifting dams become increasingly popular in China for water storage, river landscaping and environmental restoration. Inevitably, dams influence riverine morphology. Unfortunately, current understanding of this topic has remained rather limited. Here, the morphological effects of a hydraulic lifting dam on the middle Fenhe River, China are investigated. This reach features a compound channel and floodplains, and the riverbed is mainly composed of silt that can be easily eroded, indicating potential significant bed deformation. A computationally efficient depth-averaged two-dimensional shallow water hydro-sediment-morphodynamic model is employed. Unstructured meshes are refined around dam structures to accurately present topography. The numerical predictions show discrepancies of morphological responses of the main channel and floodplains to different operation schemes of the hydraulic lifting dam. This work helps to support decisions on the management of hydraulic lifting dams on the middle Fenhe River and reveals a general pattern for the morphological impact of hydraulic lifting dam.</p>

scholarly journals Current and Modified Flood Discharge Capacity of a Reach of Tigris River between Kut and Amarah Barrages

2020 ◽  
Vol 26 (2) ◽  
pp. 129-143
Author(s):  
Maysam S Abbas ◽  
Riyadh Z. Azzubaidi
Keyword(s):  
Cross Section ◽  
Discharge Capacity ◽  
Cross Sections ◽  
Flood Plain ◽  
Main Channel ◽  
Water Levels ◽  
Flood Wave ◽  
Tigris River ◽  
Flood Discharge ◽  
Lateral Inflow

This study was conducted to examine the discharge capacity of the reach of the Tigris River between Kut and Amarah Barrages of 250km in length. The examination includes simulation the current capacity of the reach by using HEC-RAS model. 247cross sections surveyed in 2012 were used in the simulation. The model was calibrated using observed discharges of 533, 800, 1025 and 3000m3/s discharged at Kut Barrage during 2013, 1995, 1995 and 1988, respectively, and its related water level at three gauge stations located along the reach. The result of calibration process indicated that the lowest Root Mean Square Error of 0.095 can be obtained when using Manning’s n coefficient of 0.026, 0.03 for the Kut- Ali Al Garbi and Ali Al Garbi- Amarah reaches respectively, and 0.03 for the flood plain of the whole reach under study. The reach under study has two lateral inflow streams, UmAljury, which joins Tigris River at station 51km, and Aljabab, which joins Tigris River at station 57km. The discharge of Aljabab varies between 0 and 400m3/s and the discharge of UmAljury varies between 0 and 50m3/s.                     The results showed that the current capacity of the main channel of the reach of the Tigris River between Kut and Amarah Barrages is 400m3/s. The water levels kept less 1m than both levees in case of discharging 1800m3/s from Kut Barrage, with no lateral inflows, and 1700m3/s with lateral inflow. The reach of Tigris River fails to accommodate the flood discharge of 3300m3/s which is the discharge of the flood of 1988 measured at Kut Barage. It can be concluded that the reach had large amount of sediment for the period from 1988 to 2012 and the reach capacity reduced to about half its capacity of 1988 during this period.                                                          The results of removing 12 islands and 2 sidebars by reshaping the current condition into trapezoidal cross-section will decrease the surface water levels by 20cm and flow of 1900m3/s can be discharged safely at Kut Barrage without any lateral inflow and 1800m3/s with lateral inflow from the tributaries. While, expand 58 narrow cross-sections that choking the flow, the water levels along the reach are lowered by an average of 20cm in addition to that 20cm when modifying the cross-sections at the islands and sidebars. In this case, flow of 2100m3/s can safely be discharged from Kut Barrage without any lateral inflow and 1900m3/s with lateral inflow. The result when modifying additional 111 cross-sections showed that the reach can safely accommodate a flood wave of 3300m3/s from Kut Barrage without any lateral inflow and 3000m3/s with lateral inflow.                                                                                                            

scholarly journals EFFECT OF LEVEE AND MAIN CHANNEL ALIGNMENTS AND FLOOD CHANNEL WIDTH ON WATER STORAGE DURING FLOOD FLOW

2002 ◽  
Vol 46 ◽  
pp. 433-438
Author(s):  
Shoji FUKUOKA ◽  
Daisuke KURISU ◽  
Alex MUTASINGWA ◽  
Tsuyoshi NAKAMURA ◽  
Masanori TAKAHASHI
Keyword(s):  
Water Storage ◽  
Main Channel ◽  
Channel Width ◽  
Flood Flow

scholarly journals Environmental DNA simultaneously informs hydrological and biodiversity characterization of an Alpine catchment

2021 ◽  
Vol 25 (2) ◽  
pp. 735-753
Author(s):  
Elvira Mächler ◽  
Anham Salyani ◽  
Jean-Claude Walser ◽  
Annegret Larsen ◽  
Bettina Schaefli ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Water Storage ◽  
Environmental Dna ◽  
Main Channel ◽  
Low Flow ◽  
Water Types ◽  
Hydrologic Processes ◽  
Naturally Occurring ◽  
Overbank Flow ◽  
Alpine System

Abstract. Alpine streams are particularly valuable for downstream water resources and of high ecological relevance; however, a detailed understanding of water storage and release in such heterogeneous environments is often still lacking. Observations of naturally occurring tracers, such as stable isotopes of water or electrical conductivity, are frequently used to track and explain hydrologic patterns and processes. Importantly, some of these hydrologic processes also create microhabitat variations in Alpine aquatic systems, each inhabited by characteristic organismal communities. The inclusion of such ecological diversity in a hydrologic assessment of an Alpine system may improve our understanding of hydrologic flows while also delivering biological information. Recently, the application of environmental DNA (eDNA) to assess biological diversity in water and connected habitats has gained popularity in the field of aquatic ecology. A few of these studies have started to link aquatic diversity with hydrologic processes but hitherto never in an Alpine system. Here, we collected water from an Alpine catchment in Switzerland and compared the genetic information of eukaryotic organisms conveyed by eDNA with the hydrologic information conveyed by naturally occurring hydrologic tracers. Between March and September 2017, we sampled water at multiple time points at 10 sites distributed over the 13.4 km2 Vallon de Nant catchment (Switzerland). The sites corresponded to three different water types and habitats, namely low-flow or ephemeral tributaries, groundwater-fed springs, and the main channel receiving water from both previous mentioned water types. Accompanying observations of typical physicochemical hydrologic characteristics with eDNA revealed that in the main channel and in the tributaries, the biological richness increases according to the change in streamflow, dq/dt, whereas, in contrast, the richness in springs increased in correlation with electrical conductivity. At the catchment scale, our results suggest that transport of additional, and probably terrestrial, DNA into water storage or flow compartments occurs with increasing streamflow. Such processes include overbank flow, stream network expansion, and hyporheic exchange. In general, our results highlight the importance of considering the at-site sampling habitat in combination with upstream connected habitats to understand how streams integrate eDNA over a catchment and to interpret spatially distributed eDNA samples, both for hydrologic and biodiversity assessments. At the intersection of two disciplines, our study provides complementary knowledge gains and identifies the next steps to be addressed for using eDNA to achieve complementary insights into Alpine water sources. Finally, we provide recommendations for future observation of eDNA in Alpine stream ecosystems.

scholarly journals Steady/Unsteady Flow Through Small Earthfill Dams

2018 ◽  
Vol 8 (1) ◽  
pp. 39-44
Author(s):  
Marius Lucian Botoș ◽  
Zsombor Kisfaludi-Bak
Keyword(s):  
Control Systems ◽  
Water Storage ◽  
Maximum Level ◽  
Point Of View ◽  
The Body ◽  
Flood Wave ◽  
Partially Saturated ◽  
Specific Complex ◽  
Flow Through ◽  
Earthfill Dams

Abstract Small earthfill dams, without permanent water storage, are simple operation constructions without any outlet operation or control systems, and which provide water storage in flood wave periods. From the seepage point of view, these simple constructions have a specific complex behavior. Even if generally the body of the dam can be considered to be homogeneous, infiltration through partially saturated materials is unsteady. The water level rapidly increases from the minimum to the maximum level as the water storage volume is relatively low.

scholarly journals Neutrosophic Logic-Based Document Summarization

2021 ◽  
Vol 2021 ◽  
pp. 1-7
Author(s):  
O. G. El Barbary ◽  
Radwan Abu Gdairi
Keyword(s):  
Relevant Information ◽  
Text Summarization ◽  
The Internet ◽  
Document Summarization ◽  
Neutrosophic Logic ◽  
Increasing Knowledge ◽  
Main Factor ◽  
Word Feature

Nowadays, rich quantity of information is offered on the Net which makes it hard for the clients to detect necessary information. Programmed techniques are desirable to effectively filter and search useful data from the Net. The purpose of purported text summarization is to get satisfied content handling with information variety. The main factor of document summarization is to extract benefit feature. In this paper, we extract word feature in three group called important words. Also, we extract sentence feature depending on the extracted words. With increasing knowledge on the Internet, it turns out to be an extremely time-consuming, exhausting, and boring mission to read the whole content and papers and get the relevant information on precise topics

scholarly journals Environmental DNA simultaneously informs hydrological and biodiversity characterization of an Alpine catchment

2020 ◽  
Author(s):  
Elvira Mächler ◽  
Anham Salyani ◽  
Jean-Claude Walser ◽  
Annegret Larsen ◽  
Bettina Schaefli ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Water Storage ◽  
Environmental Dna ◽  
Main Channel ◽  
Low Flow ◽  
Multiple Time ◽  
Water Types ◽  
Naturally Occurring ◽  
Overbank Flow ◽  
Alpine System

Abstract. Alpine streams are particularly valuable for downstream water resources and of high ecological relevance, however a detailed understanding of water storage and release in such heterogeneous environments is still often lacking. Observations of naturally occurring tracers, such as stable isotopes of water or electrical conductivity, are frequently used to track and explain hydrological patterns and processes. Importantly, some of these hydrological processes also create microhabitat variations in Alpine aquatic systems, each inhabited by characteristic organismal communities. The inclusion of such ecological diversity in a hydrologic assessment of an Alpine system may improve our understanding of hydrologic flows while also delivering biological information. Recently, the application of environmental DNA (eDNA) to assess biological diversity in water and connected habitats has gained popularity in the field of aquatic ecology. A few of these studies have started to link aquatic diversity with hydrologic processes, but hitherto never in an Alpine system. Here, we collected water from an Alpine catchment in Switzerland and compared the genetic information of eukaryotic organisms conveyed by eDNA with the hydrologic information conveyed by naturally-occurring, hydrologic tracers. Between March and September 2017, we sampled water at multiple time points at 10 sites distributed over the 13.4 km2 Vallon de Nant catchment (Switzerland). The sites corresponded to three different water types and habitats, namely low flow or ephemeral tributaries, groundwater fed springs, and the main channel receiving water from both previous mentioned water types. Accompanying observations of typical physico-chemical hydrologic characteristics with eDNA revealed that in the main channel and in the tributaries the biological richness increases according to change in streamflow, dq/dt. Whereas, in contrast, the richness in springs increased in correlation with electrical conductivity. At the catchment scale, our results suggest that transport of additional, and probably terrestrial, DNA into water storage or flow compartments occurs with increasing streamflow. Such processes include overbank flow, stream network expansion, and hyporheic exchange. In general, our results highlight the importance of considering the at-site sampling habitat in combination with upstream connected habitats to understand how streams integrate eDNA over a catchment and to interpret spatially distributed eDNA samples, both for hydrologic and biodiversity assessments. At the intersection of two disciplines, our study provides complementary knowledge gains and identifies the next steps to be addressed for using eDNA to achieve complementary insights into Alpine water sources. Finally, we provide recommendations for future observation of eDNA in Alpine stream ecosystems.

scholarly journals Assessing the retention capacity of a floodplain using a 2D numerical model

2010 ◽  
Vol 58 (4) ◽  
pp. 221-232 ◽  
Author(s):  
Jana Valentová ◽  
Petr Valenta ◽  
Lenka Weyskrabová
Keyword(s):  
Numerical Model ◽  
Water Storage ◽  
Wave Transformation ◽  
Flood Wave ◽  
Retention Capacity ◽  
Water Storage Capacity ◽  
Meandering Channels ◽  
Linear Reservoir ◽  
Flood Flow ◽  
2D Numerical Model

Assessing the retention capacity of a floodplain using a 2D numerical modelThis paper presents a method for assessing the retention capacity of a floodplain in the course of flooding and for estimating the significance of its water storage for transforming a flood wave. The method is based on two-dimensional numerical modeling of the flood flow in a river channel and in the adjacent floodplains, and is suitable for cases when the morphology of the flooding area is variable and complex, e.g. broad inundation areas with meandering channels. The approach adopted here enables us to quantify the retention capacity for inundation areas of various characters and with various land uses, and provides a tool for estimating the efficiency of possible measures for increasing the water storage capacity of a floodplain. The retention capacity is estimated using an evaluation of a series of detailed flood flow modeling results; the flood wave transformation effect is predicted with the aim of creating a non-linear reservoir model. A parametric study of the floodplain retention capacity for the upper branch of the Lužnice River is presented here, and the results for the current state and for various hypothetical scenarios of changes in geometry and land use are evaluated and compared.

What sentimentalists should say about emotion

2019 ◽  
Vol 42 ◽  
Author(s):  
Charlie Kurth
Keyword(s):  
Moral Judgment ◽  
Recent Work ◽  
Relevant Information ◽  
Moral Cognition ◽  
Multilevel Structure

Abstract Recent work by emotion researchers indicates that emotions have a multilevel structure. Sophisticated sentimentalists should take note of this work – for it better enables them to defend a substantive role for emotion in moral cognition. Contra May's rationalist criticisms, emotions are not only able to carry morally relevant information, but can also substantially influence moral judgment and reasoning.

Automatic analysis of Kikuchi diffraction patterns

1994 ◽  
Vol 52 ◽  
pp. 900-901
Author(s):  
H. Weiland ◽  
D. P. Field
Keyword(s):  
Electron Beam ◽  
Electron Microscope ◽  
Spatial Resolution ◽  
Relevant Information ◽  
Crystalline Materials ◽  
Large Size ◽  
Transmission Electron ◽  
New Type ◽  
Diffraction Patterns ◽  
Orientation Determination

Recent advances in the automatic indexing of backscatter Kikuchi diffraction patterns on the scanning electron microscope (SEM) has resulted in the development of a new type of microscopy. The ability to obtain statistically relevant information on the spatial distribution of crystallite orientations is giving rise to new insight into polycrystalline microstructures and their relation to materials properties. A limitation of the technique in the SEM is that the spatial resolution of the measurement is restricted by the relatively large size of the electron beam in relation to various microstructural features. Typically the spatial resolution in the SEM is limited to about half a micron or greater. Heavily worked structures exhibit microstructural features much finer than this and require resolution on the order of nanometers for accurate characterization. Transmission electron microscope (TEM) techniques offer sufficient resolution to investigate heavily worked crystalline materials.Crystal lattice orientation determination from Kikuchi diffraction patterns in the TEM (Figure 1) requires knowledge of the relative positions of at least three non-parallel Kikuchi line pairs in relation to the crystallite and the electron beam.

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