Channel form and adjustment: characterization, measurement, interpretation and analysis

Simon, Andrew; Castro, Janine; Rinaldi, Massimo

doi:10.1002/9781118648551.ch11

Cited by 9 publications

(3 citation statements)

References 113 publications

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“…Despite its simplicity and (as our results suggests) usefull application to describe tidal and bed level data, exponential decay functions are rarely, if ever, used to quantify adaptation timescales. Exponential functions have been fitted to bed level data in order to distinguish erosion minima and multiple erosion phases (Simon et al, 2016) but not, to the authors knowledge, to extract adaptation timescales. A change in tidal range has not been quantified using exponential decay functions (again to the authors knowledge), and therefore also never to extract adaptation timescales.…”

Section: Methodsmentioning

confidence: 99%

Adaptation timescales of estuarine systems to human interventions

Maren

Alonso

Engels³

et al. 2023

Front. Earth Sci.

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Many estuaries and tidal basins are strongly influenced by various human interventions (land reclamations, infrastructure development, channel deepening, dredging and disposal of sediments). Such interventions lead to a range of hydrodynamic and morphological responses (a changing channel depth, tidal amplitude and/or suspended sediment concentration). The response time of a system to interventions is determined by the processes driving this change, the size of the system, and the magnitude of the intervention. A quantitative understanding of the response time to an intervention therefore provides important insight into the processes driving the response. In this paper we develop and apply a methodology to estimate the response timescales of human interventions using available morphological and hydraulic data. Fitting an exponential decay function to data with sufficient temporal resolution yields an adaptation timescale (and equilibrium value) of the tidal range and deposited sediment volumes. The method has been applied in the Dutch Wadden Sea, where two large basins were reclaimed and where long-term and detailed bathymetric maps are available. Exponential fitting the morphological data revealed that closure of a very large part of a tidal basin in the Wadden Sea initially led to internal redistribution and import of coarse and fine sediments, and was followed by a phase of extensive redistribution while only fine-grained sediments are imported. Closure of a smaller part of a smaller basin led to shorter response timescales, and these response timescales are also more sensitive to rising mean sea levels or high waters. The method has also been applied to tidal water level observations in the Scheldt and Ems estuaries. Exponential fits to tidal data reveal that adaptation timescales are shortest at the landward limit of dredging. The adaptation time increases in the landward direction because of retrogressive erosion (Scheldt) or lowering of the hydraulic roughness (Ems). The seaward increase in adaptation time is related to the seaward widening of both systems.

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Section: Methodsmentioning

confidence: 99%

Adaptation timescales of estuarine systems to human interventions

Maren

Alonso

Engels³

et al. 2023

Front. Earth Sci.

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“…The channel banks were easily detected since the Kolubara River banks are mostly arable land, with non-vegetated (or grass only) parts. For the purpose of consistency, one person carried out all of the digitizing; furthermore, the two digitized channel boundary lines were processed using GeoMedia Professional software tools to generate a channel centerline, which was used to calculate the channel length and channel migration rate [56][57][58][59][60].…”

Section: Methodsmentioning

confidence: 99%

Spatial and Temporal Variability of Bank Erosion during the Period 1930–2016: Case Study—Kolubara River Basin (Serbia)

Dragićević

Pripužić

Živković

et al. 2017

Water

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Abstract:The fluvial process is characterized by an intense meandering riverbed. The aim of this study was to perform a reconstruction of the lateral migration of a 15 km length of an active meandering river during the period 1930-2016. River morphological changes were analyzed and quantified from cadastral maps and aerial photographs as well as by geodetic survey and GIS. Hydrological characteristics and extreme hydrological events were evaluated in relation to bank erosion rate. The rate of bank erosion was markedly different from the long-term studied meanders, just like in the short-term period. During the 87 years of observation (from 1930 to 2016), the length of the Kolubara River was enlarged by 3.44 km. The average migration rate of the Kolubara River for monitored meanders in the period 1930-2010 was 1.9 m·year −1 , while in the period 2010-2016, the average migration rate was 3.3 m·year −1 . The rate of bank erosion was more intensive across the entire short-term period than during the longer period, and the maximum annual rate of bank erosion during the period 2010-2016 varied between 0.3 and 11.5 m. It is very likely that in the period from 2010, frequent discharge variations and rapid change of its extreme values caused more intensive bank erosion. These research results will be valuable for river channel management, engineering (soft and hard engineering), and planning purposes (predicting changes in river channel form) in the Kolubara River Basin.

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“…Los procesos geomorfológicos y sus formas asociadas determinan la estructura de un sistema fluvial (Brierley et al, 2013), y ambos componentes son críticos para la rehabilitación sostenible de los ecosistemas acuáticos (Brierley et al, 2002). En los ríos aluviales, la dinámica y las características geomorfológicas del cauce reflejan las condiciones biofísicas de la cuenca y los procesos que ahí se desarrollan (Simon et al, 2016;Ibisate et al, 2011). No obstante, las condiciones "duras" de los ríos (tramos) en roca actúan como elementos control de la dinámica longitudinal del río (Garzón et al, 2008;Wohl, 1998).…”

Section: Geodiversidad Fluvial Y Gestión: Una "Necesidad Necesaria"unclassified

Aproximación a la identificación y caracterización de ríos en roca a escala regional mediante variables topo-geomorfológicas (Galicia, Noroeste de la Península Ibérica)

García

Pérez‐Alberti²

2022

CGUV

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Las clasificaciones de ríos son un procedimiento técnico de utilidad para simplificar la realidad y discriminar en tipos con características homogéneas. El ensayo experimental que se presenta, desarrollado sobre la red fluvial de Galicia, tiene el objetivo de combinar Sistemas de Información Geográfica y tres variables geomorfológicas (litología, pendiente y densidad de fracturas) para identificar potenciales tramos de ríos en roca. El método aplicado se estructuró en cuatro etapas secuenciales: (i) inventariado de tramos en roca, (ii) caracterización de los tramos inventariados, (iii) tipificación de la red de drenaje, y (iv) validación del método aplicado. Los resultados obtenidos arrojan una primera cartografía de probabilidad de presencia de ríos en roca para más de 30.000 km de cauces. Un 37% de la red tiene una probabilidad alta de ser río en roca y un 21% una probabilidad baja o nula. El 42% restante se mueve en una probabilidad media. Conocer la distribución espacial de este tipo de ríos debería ser de utilidad para los organismos de cuenca y el establecimiento de protocolos de actuación que consideren, primero, las características de los ríos en roca en la gestión de las masas de agua por su singularidad y repercusión en la dinámica del río, y, segundo, el florecimiento de figuras de protección basadas en la geodiversidad.

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Channel form and adjustment: characterization, measurement, interpretation and analysis

Cited by 9 publications

References 113 publications

Adaptation timescales of estuarine systems to human interventions

Adaptation timescales of estuarine systems to human interventions

Spatial and Temporal Variability of Bank Erosion during the Period 1930–2016: Case Study—Kolubara River Basin (Serbia)

Aproximación a la identificación y caracterización de ríos en roca a escala regional mediante variables topo-geomorfológicas (Galicia, Noroeste de la Península Ibérica)

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