scholarly journals Vegetation and Geomorphic Connectivity in Mountain Fluvial Systems

Water ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 593
Author(s):  
Piotr Cienciala
Keyword(s):  
Literature Review ◽  
Clastic Material ◽  
Channel Networks ◽  
Lateral Connectivity ◽  
Fluvial Systems ◽  
Sediment Fluxes ◽  
Emergent Phenomena ◽  
Longitudinal Connectivity ◽  
Basin Scale ◽  
Material Fluxes

Rivers are complex biophysical systems, constantly adjusting to a suite of changing governing conditions, including vegetation cover within their basins. This review seeks to: (i) highlight the crucial role that vegetation’s influence on the efficiency of clastic material fluxes (geomorphic connectivity) plays in defining mountain fluvial landscape’s behavior; and (ii) identify key challenges which hinder progress in the understanding of this subject. To this end, a selective literature review is carried out to illustrate the pervasiveness of the plants’ effects on geomorphic fluxes within channel networks (longitudinal connectivity), as well as between channels and the broader landscape (lateral connectivity). Taken together, the reviewed evidence lends support to the thesis that vegetation-connectivity linkages play a central role in regulating geomorphic behavior of mountain fluvial systems. The manuscript is concluded by a brief discussion of the need for the integration of mechanistic research into the local feedbacks between plants and sediment fluxes with basin-scale research that considers emergent phenomena.

Sediment slugs: large-scale fluctuations in fluvial sediment transport rates and storage volumes

1995 ◽  
Vol 19 (4) ◽  
pp. 500-519 ◽  
Author(s):  
A.P. Nicholas ◽  
P.J. Ashworth ◽  
M.J. Kirkby ◽  
M.G. Macklin ◽  
T. Murray
Keyword(s):  
Sediment Transport ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Event Scale ◽  
Fluvial Sediment ◽  
Sediment Routing ◽  
Basin Scale ◽  
Wide Range ◽  
And Storage ◽  
Fluvial Sediment Transport

Variations in fluvial sediment transport rates and storage volumes have been described previously as sediment waves or pulses. These features have been identified over a wide range of temporal and spatial scales and have been categorized using existing bedform classifications. Here we describe the factors controlling the generation and propagation of what we term sediment slugs. These can be defined as bodies of clastic material associated with disequilibrium conditions in fluvial systems over time periods above the event scale. Slugs range in magnitude from unit bars (Smith, 1974) up to sedimentary features generated by basin-scale sediment supply disturbances (Trimble, 1981). At lower slug magnitudes, perturbations in sediment transport are generated by local riverbank and/or bed erosion. Larger-scale features result from the occurrence of rare high- magnitude geomorphic events, and the impacts on water and sediment production of tectonics, glaciation, climate change and anthropogenic influences. Simple sediment routing functions are presented which may be used to describe the propagation of sediment slugs in fluvial systems. Attention is drawn to components of the fluvial system where future research is urgently required to improve our quantitative understanding of drainage-basin sediment dynamics.

scholarly journals Efficacy of bedrock erosion by subglacial water flow

2015 ◽  
Vol 3 (3) ◽  
pp. 849-908 ◽  
Author(s):  
F. Beaud ◽  
G. E. Flowers ◽  
J. G. Venditti
Keyword(s):  
Water Flow ◽  
Water Pressure ◽  
Water Discharge ◽  
Sediment Supply ◽  
Fluvial Systems ◽  
Glacial Meltwater ◽  
Erosion Rates ◽  
Subglacial Environment ◽  
Basin Scale ◽  
Bedrock Erosion

Abstract. Bedrock erosion by sediment-bearing subglacial water remains little-studied, however the process is thought to contribute to bedrock erosion rates in glaciated landscapes and is implicated in the excavation of tunnel valleys and the incision of inner gorges. We adapt physics-based models of fluvial abrasion to the subglacial environment, assembling the first model designed to quantify bedrock erosion caused by transient subglacial water flow. The subglacial drainage model consists of a one-dimensional network of cavities dynamically coupled to one or several Röthlisberger channels (R-channels). The bedrock erosion model is based on the tools and cover effect, whereby particles entrained by the flow impact exposed bedrock. We explore the dependency of glacial meltwater erosion on the structure and magnitude of water input to the system, the ice geometry and the sediment supply. We find that erosion is not a function of water discharge alone, but also depends on channel size, water pressure and on sediment supply, as in fluvial systems. Modelled glacial meltwater erosion rates are one to two orders of magnitude lower than the expected rates of total glacial erosion required to produce the sediment supply rates we impose, suggesting that glacial meltwater erosion is negligible at the basin scale. Nevertheless, due to the extreme localization of glacial meltwater erosion (at the base of R-channels), this process can carve bedrock (Nye) channels. In fact, our simulations suggest that the incision of bedrock channels several centimetres deep and a few meters wide can occur in a single year. Modelled incision rates indicate that subglacial water flow can gradually carve a tunnel valley and enhance the relief or even initiate the carving of an inner gorge.

scholarly journals Marine and anthropogenic controls on the estuary of the Suriname River over the past 50 years

2016 ◽  
Vol 95 (4) ◽  
pp. 419-428
Author(s):  
K. Gersie ◽  
P.G.E.F. Augustinus ◽  
R.T. Van Balen
Keyword(s):  
Tidal Current ◽  
River Flow ◽  
Sediment Load ◽  
Anthropogenic Activities ◽  
Fluvial Systems ◽  
Sediment Fluxes ◽  
Fine Grained ◽  
The Past ◽  
The Impact ◽  
Strong Tidal Current

AbstractHumans have played an important role in fluvial systems because of the impact of their land-use activities, frequently leading to degradation of environmental conditions. Rivers, which are the primary agents in sediment transport, have thus been subject to changes in sediment fluxes. The Suriname River has been affected by anthropogenic activities since colonial times, and has experienced strong discharge and sediment-load changes since the construction of the Afobaka Dam in 1964. The river's estuary sediments largely consist of fine-grained sediments, originating, ultimately, from the Amazon River and transported by the strong tidal current. The influence of this tidal current is diminished at the head of the estuary, allowing the river flow to become dominant. Also remarkable is the interaction of the Suriname River and the westward-migrating mudbanks which is evident in the changing magnitude and volume of Braamspunt, a mudcape located at the mouth of the estuary. The regulated discharge of the river results in a change of the river's morphology, resulting, among other things, in the growth of river bars.

Paleohydraulic investigation of the Ebro Basin: Implications for Mars

2021 ◽  
Author(s):  
Heath Geil-Haggerty
Keyword(s):  
Water Discharge ◽  
Sedimentary Basins ◽  
Mass Conservation ◽  
Sediment Supply ◽  
Sediment Flux ◽  
River Channels ◽  
Ebro Basin ◽  
Fluvial Systems ◽  
Sediment Size ◽  
Basin Scale

<p>The stratigraphy preserved in Earth’s sedimentary basins offers a record of how landscapes have evolved with time.  This stratigraphy provides insights into the dynamic processes that shaped the surface of the earth.  Fluvial stratigraphy contains many elements that can be used to recreate past conditions in ancient river channels.  Paleohydraulic reconstruction uses measurements of fluvial stratigraphy to model the conditions in the system that created them.  This allows us to answer questions related to water discharge, sediment flux, and duration of fluvial activity.  These are key questions when investigated in the context of Mars.  Paleohydraulic models can be used as compelling analogs for similar systems on Earth as well as Mars and other rocky planets.           </p><p>This study examines what the record of Oligocene-Miocene fluvial stratigraphy in northeastern Spain’s Ebro Basin can tell us about water discharge and sediment flux across distributive fluvial systems at a basin scale.  The Cenozoic stratigraphy of northeastern Spain’s triangular shaped Ebro Basin embodies a classic example of the formation of a closed sedimentary basin.  The Ebro Basin contains a number of remarkably well exposed fluvial sedimentary deposits.  These deposits outcrop as distinctive laterally contiguous channel sand bodies.  Clastic sediment supply in the Ebro Basin is largely governed by tectonic uplift and basin subsidence related to the Pyrenean orogen with peripheral contributions from the Catalan Coast and Iberian Ranges.  We test the idea that the record of conditions in the fluvial systems should reflect the record of lacustrine chemical sediments through sediment mass conservation.  In order to test this hypothesis measurements of bedform height, barform height, sediment size, and paleochannel dimensions were collected in the field.  Our paleohydraulic model uses previously derived theoretical and empirical relationships to recreate the conditions in these ancient fluvial systems.  These results are scaled up by accounting for drainage density and intermittency in order to address the principal question at a basin scale.  Paleodischarges from the fluvial sediments are comparable to those from river chemistry calculations for the lacustrine facies. </p>

Improving Upstream and Downstream Fish Passage at Retis Dam on Hârtibaciu River - Sibiu County (Transylvania)

2017 ◽  
Vol 17 (1) ◽  
pp. 47-57 ◽  
Author(s):  
Răzvan Voicu ◽  
Pete Baki
Keyword(s):  
Fish Fauna ◽  
Fish Passage ◽  
Hydraulic Structures ◽  
Fish Migration ◽  
Lateral Connectivity ◽  
Longitudinal Connectivity ◽  
Barbatula Barbatula ◽  
Cobitis Taenia ◽  
Misgurnus Fossilis ◽  
Squalius Cephalus

Abstract Retis (dam Retis), hydro-technical development like many other transverse hydraulic structures cancel the longitudinal connectivity of Hârtibaciu water course, blocking the migration of different (migrating) species of fish in the river. Also, the lateral connectivity was heavily affected on this water course at a rate of 60%. Therefore, proposing engineering solutions to recover both (lateral and longitudinal) types of connectivity is vital to restore the local ecobiom. The purpose of this article is to establish longitudinal connectivity through an engineering solution that facilitates the fish migration upstream - downstream of Retis dam. This paper proposes an engineered fish passage solution for Retiș Dam on the Hârtibaciu River, using the criteria described in the Water Framework Directive 2000/60/EC document. Anthropogenic barriers located in the Hârtibaciu River disrupt and delay movement of local fish fauna including: Alburnoides bipunctatus (Bloch, 1782), Squalius cephalus (Linnaeus, 1758), Alburnus alburnus (Linnaeus, 1758), Rhodeus amarus (Bloch, 1782), Gobio gobio (Linnaeus, 1758), Romanogobio kessleri (Dybowski, 1862), Barbatula barbatula (Linnaeus, 1758), Barbus meridionalis Risso, 1827 Misgurnus fossilis (Linnaeus, 1758), Cobitis taenia Linnaeus, 1758, Cobitis romanica (Băcescu, 1943), and Cobitis aurata (De Filippi, 1863).

Three Dimensions of the Ecological Connectivity of Fluvial Greenway

2014 ◽  
Vol 1065-1069 ◽  
pp. 2785-2788
Author(s):  
Shuai Sun
Keyword(s):  
Cross Section ◽  
Flood Pulse ◽  
Three Dimensions ◽  
Flood Pulse Concept ◽  
Lateral Connectivity ◽  
Multiple Dimensions ◽  
Longitudinal Connectivity ◽  
Natural Flow ◽  
Section Design ◽  
River Cross Section

Fluvial greenway connectivity has multiple dimensions, so it is the complex ecosystems of nature. The longitudinal connectivity of fluvial greenway is directly related to the natural flow of water, and is sensible and cognizable. The lateral Connectivity of fluvial greenway is closely linked to the Flood Pulse Concept and river cross-section design. The vertical connectivity of fluvial greenway refers to the vertical materials and energy circulation performance and the biocoenosis relevancy in the cross section of the river. They constitute the complicated continuum system of fluvial greenway.

scholarly journals Human impact on fluvial systems in Europe with special regard to today’s river restorations

2021 ◽  
Vol 33 (1) ◽  
Author(s):  
Anna-Lisa Maaß ◽  
Holger Schüttrumpf ◽  
Frank Lehmkuhl
Keyword(s):  
Human Impact ◽  
Sediment Load ◽  
Human Impacts ◽  
Channel Morphology ◽  
Natural Sediment ◽  
Fluvial Systems ◽  
River Floodplain ◽  
The Holocene ◽  
Sediment Fluxes ◽  
Fluvial Morphology

AbstractClimate, geology, geomorphology, soil, vegetation, geomorphology, hydrology, and human impact affect river–floodplain systems, especially their sediment load and channel morphology. Since the beginning of the Holocene, human activity is present at different scales from the catchment to the channel and has had an increasing influence on fluvial systems. Today, many river–floodplain systems are transformed in course of river restorations to “natural” hydrodynamic and morphodynamic conditions without human impacts. Information is missing for the historical or rather “natural” as well as for the present-day situation. Changes of the “natural” sediment fluxes in the last centuries result in changes of the fluvial morphology. The success of river restorations depends on substantial knowledge about historical as well as present-day fluvial morphodynamics. Therefore, it is necessary to analyze the consequences of historical impacts on fluvial morphodynamics and additionally the future implications of present-day human impacts in course of river restorations. The objective of this review is to summarize catchment impacts and river channel impacts since the beginning of the Holocene in Europe on the fluvial morphodynamics, to critically investigate their consequences on the environment, and to evaluate the possibility to return to a “natural” morphological river state.

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