Impact of dredging and dumping on the stability of ebb–flood channel systems

Jeuken, M.; Wang, Zheng Bing

doi:10.1016/j.coastaleng.2009.12.004

Cited by 64 publications

(65 citation statements)

References 8 publications

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“…These main channels are separated by subtidal and intertidal shoals and linked by connecting channels. (Van den Berg et al 1996;Jeuken 2000;Van Veen et al 2005;Toffolon and Crosato 2007). Winterwerp et al (2001) schematized this system into a chain of so-called macro-cells and meso-cells (Fig.…”

Section: Physical System Descriptionmentioning

confidence: 99%

“…Smaller-scale connecting channels link the large ebb and flood channels in macro-cells, forming meso-cells. These smaller channels often display a quasi-cyclic morphologic behaviour, characterized by processes of channel origination, migration and degeneration at a timescale of years to decades (Jeuken 2000;Van Veen et al 2005).…”

Section: Physical System Descriptionmentioning

confidence: 99%

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Eco-Morphological Problems in the Yangtze Estuary and the Western Scheldt

et al. 2011

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This paper compares the Yangtze Estuary in China and the Western Scheldt Estuary in The Netherlands by their morphodynamic and ecological systems, their engineering works and estuarine management issues, and the major challenges in studying them. Physically speaking, the two estuaries are very different. The Yangtze Estuary is much larger and much more influenced by the upstream river than the Western Scheldt. Yet, they also have a number of morphological and ecological features in common. Both estuaries have a multi-channel system and extensive intertidal flats and wetlands with ecologically valuable flora and fauna. These eco-morphological systems are influenced by similar societal developments and human activities. Examples of the latter are engineering works and dredging activities for improving and maintaining the navigation channels, and shoreline management activities including land reclamations and setbacks. The fundamental eco-morphological phenomena that remain to be analysed and understood are the same for the two estuaries and will be discussed in this paper.

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Section: Physical System Descriptionmentioning

confidence: 99%

Section: Physical System Descriptionmentioning

confidence: 99%

Eco-Morphological Problems in the Yangtze Estuary and the Western Scheldt

et al. 2011

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“…More extreme changes in the bed level of mudflats can, however, happen during storm events, either by erosion of the top centimetres of the sediment or by deposition of new sediment (Hu et al, 2015;Marion et al, 2009). Besides natural processes, anthropogenic factors influencing sedimentation are prominent in the estuary, among which dredging in the main channels to ensure access to the port of Antwerp and dumping of the dredged material to retain sediment within the estuary are the most important (Jeuken and Wang, 2010;Meire et al, 2005). Most of this dredged sediment is disposed of near shoals and tidal flats and can thus affect the intertidal ecosystem (Bolam and Whomersley, 2005;De Vriend et al, 2011;Zheng, 2015).…”

Section: Introductionmentioning

confidence: 99%

Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

et al. 2018

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Abstract. Human activities, among which dredging and land use change in river basins, are altering estuarine ecosystems. These activities may result in changes in sedimentary processes, affecting biodiversity of sediment macrofauna. As macrofauna controls sediment chemistry and fluxes of energy and matter between water column and sediment, changes in the structure of macrobenthic communities could affect the functioning of an entire ecosystem. We assessed the impact of sediment deposition on intertidal macrobenthic communities and on rates of an important ecosystem function, i.e. sediment community oxygen consumption (SCOC). An experiment was performed with undisturbed sediment samples from the Scheldt river estuary (SW Netherlands). The samples were subjected to four sedimentation regimes: one control and three with a deposited sediment layer of 1, 2 or 5 cm. Oxygen consumption was measured during incubation at ambient temperature. Luminophores applied at the surface, and a seawater-bromide mixture, served as tracers for bioturbation and bio-irrigation, respectively. After incubation, the macrofauna was extracted, identified, and counted and then classified into functional groups based on motility and sediment reworking capacity. Total macrofaunal densities dropped already under the thinnest deposits. The most affected fauna were surficial and low-motility animals, occurring at high densities in the control. Their mortality resulted in a drop in SCOC, which decreased steadily with increasing deposit thickness, while bio-irrigation and bioturbation activity showed increases in the lower sediment deposition regimes but decreases in the more extreme treatments. The initial increased activity likely counteracted the effects of the drop in low-motility, surficial fauna densities, resulting in a steady rather than sudden fall in oxygen consumption. We conclude that the functional identity in terms of motility and sediment reworking can be crucial in our understanding of the regulation of ecosystem functioning and the impact of habitat alterations such as sediment deposition.

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“…Differences in bed-level profiles between ideal and non-ideal estuaries are further enhanced by damming, dredging, dumping, land reclamation and other human engineering (e.g. O'Connor, 1987;Wang and Winterwerp, 2001;Lesourd et al, 2001;Jeuken and Wang, 2010;Wang et al, 2015). All these natural deviations from the ideal 5 estuary mean that there is no straightforward relation between the planform geometry of the estuary and the hypsometry or distribution of depths.…”

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confidence: 99%

“…For example, landward and seaward of the pointbar in the Western Scheldt (Plaat van Ossenisse) transects were inclined, covering a larger part of the channel than perpendicular transects, resulting in higher z-values as a consequence of the apparent channel- For the Western Scheldt and Eems it is known at which locations major dredging and dumping takes place (e.g. Swinkels et al, 2009;Jeuken and Wang, 2010;Bolle et al, 2010;Dam et al, 2015;Plancke and Vos, 2016). Even though the resulting z-values at these locations do not cause major outliers, the quality of fits are typically lower and the inverted Strahler function 5 (Eq.4) fitted better.…”

mentioning

confidence: 99%

Morphology of bar-built estuaries: relation between planform shape and depth distribution

Leuven

Selaković

Kleinhans

2018

Preprint

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Abstract. Fluvial-tidal transitions in estuaries are used as major shipping fairways and are characterised by complex bar and channel patterns with a large biodiversity. Habitat suitability assessment and study of interactions between morphology and ecology therefore require bathymetric data. While imagery offers data of planform estuary dimensions, only for a few natural estuaries bathymetries are available. Here we study the relation between along-channel planform geometry, obtained as the outline from imagery, and hypsometry, which characterises the distribution of along-channel and cross-channel bed-levels. 5We fitted the original function of Strahler (1952) to bathymetric data along four natural estuaries. Comparison to planform estuary shape shows that hypsometry is concave at narrow sections with large channels, while complex bar morphology results in more convex hypsometry. We found a relation between hypsometric function shape and the degree to which the estuary width deviates from an ideal convergent estuary, which is calculated from river width and mouth width. This implies that the occurring bed level distributions depend on inherited Holocene topography and lithology. Our new empirical function 10 predicts hypsometry and along-channel variation in intertidal and subtidal width. Combination with the tidal amplitude allows an estimate of inundation duration. A validation of the results on available bathymetry shows that predictions of intertidal and subtidal area are accurate within a factor 2 for estuaries of different size and character. Locations with major human influence deviate from the general trends, because dredging, dumping, land reclamation and other engineering measures cause local deviations from the expected bed-level distributions. The bathymetry predictor can be used to characterise and predict 15 estuarine subtidal and intertidal morphology in data-poor environments.

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Impact of dredging and dumping on the stability of ebb–flood channel systems

Cited by 64 publications

References 8 publications

Eco-Morphological Problems in the Yangtze Estuary and the Western Scheldt

Eco-Morphological Problems in the Yangtze Estuary and the Western Scheldt

Functional trait responses to sediment deposition reduce macrofauna-mediated ecosystem functioning in an estuarine mudflat

Morphology of bar-built estuaries: relation between planform shape and depth distribution

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