A laboratory study on the behavior of mud from the Western Scheldt under tidal conditions

Winterwerp, Johan C.; Cornelisse, John M.; Kuijper, C.

doi:10.1029/ce042p0295

Cited by 14 publications

(17 citation statements)

References 9 publications

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“…Our experiments have some similarities with those of Winterwerp et al (1993), in which the same sediments were subjected to several "tidal" cycles of erosion and deposition. In Winterwerp et al (1993) experiments the bed was deposited from the water column, was highly erodible, suspended sediment concentration reached values up to 10 g L −1 , and fluid mud formed in the slack water phase.…”

Section: Introductionmentioning

confidence: 52%

“…In Winterwerp et al (1993) experiments the bed was deposited from the water column, was highly erodible, suspended sediment concentration reached values up to 10 g L −1 , and fluid mud formed in the slack water phase. On the contrary, our experiment had placed beds, which are known to be well consolidated and are likely to experience Type II erosion (Winterwerp et al, 2012).…”

Section: Introductionmentioning

confidence: 99%

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Repeated erosion of cohesive sediments with biofilms

2014

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Abstract. This study aims to explore the interplay between biofilms and erodability of cohesive sediments. Erosion experiments were run in four laboratory annular flumes with natural sediments. After each erosion the sediment was allowed to settle, mimicking intermittent physical processes like tidal currents and waves. The time between consecutive erosion events ranged from 1 to 12 days. Turbidity of the water column caused by sediment resuspension was used to determine the erodability of the sediments with respect to small and moderate shear stresses. Erodability was also compared on the basis of the presence of benthic biofilms, which were quantified using a Pulse-Amplitude Modulation (PAM) Underwater Fluorometer. We found that frequent erosion lead to the establishment of a weak biofilm, which reduced sediment erosion at small shear stresses (around 0.1 Pa). If prolonged periods without erosion were present, the biofilm fully established, resulting in lower erosion at moderate shear stresses (around 0.4 Pa). We conclude that an unstructured extracellular polymeric substances (EPS) matrix always affect sediment erodability at low shear stresses, while only a fully developed biofilm mat can reduce sediment erodability at moderate shear stresses.

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Section: Introductionmentioning

confidence: 52%

Section: Introductionmentioning

confidence: 99%

Repeated erosion of cohesive sediments with biofilms

2014

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“…Similar features were reported in other Chinese turbid estuaries, e.g., the Hangzhou Bay (Shi, 1998), the Jiaojiang River estuary (Jiang and Wolanski, 1998). Theoretical and experimental studies of those features can be found in the literature (e.g., Smith and Kirby, 1989;Adams et al, 1993;Mehta and Srinivas, 1993;Scarlatos and Mehta, 1993;Winterwerp et al, 1993). Those interfacial wave motions could enhance turbulence and hence affect vertical fine sediment transport.…”

Section: Significance Of Fine-sediment Plumesmentioning

confidence: 96%

Bottom fine sediment boundary layer and transport processes at the mouth of the Changjiang Estuary, China

Shi

Zhang

Hamilton

2006

Journal of Hydrology

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“…We postulate that these fluctuations are induced by internal waves on the mud-water interface. At the interface of such two-layer systems, internal waves are generated, known as Kelvin-Helmholtz instabilities or Holmboe waves (Winterwerp et al 1992). Such progressive internal waves have been explicitly measured on the fluid mud-water interface just down-estuary of Leerort with acoustic methods.…”

Section: Spm Variations On the Semi-diurnal Tidal Timescalementioning

confidence: 99%

SPM response to tide and river flow in the hyper-turbid Ems River

et al. 2017

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In this paper, we analyse the behaviour of fine sediments in the hyper-turbid Lower Ems River, with focus on the river's upper reaches, a stretch of about 25 km up-estuary of Terborg. Our analysis is based on long records of suspended particulate matter (SPM) from optical backscatter (OBS) measurements close to the bed at seven stations along the river, records of salinity and water level measurements at these stations, acoustic measurements on the vertical mud structure just up-estuary of Terborg and oxygen profiles in the lower 3 m of the water column close to Leerort and Terborg. Further, we use cross-sectionally averaged velocities computed with a calibrated numerical model. Distinction is made between four timescales, i.e. the semi-diurnal tidal timescale, the springneap tidal timescale, a timescale around an isolated peak in river flow (i.e. about 3 weeks) and a seasonal timescale. The data suggest that a pool of fluid/soft mud is present in these upper reaches, from up-estuary of Papenburg to a bit downestuary of Terborg. Between Terborg and Gandersum, SPM values drop rapidly but remain high at a few gram per litre. The pool of fluid/soft mud is entrained/mobilized at the onset of flood, yielding SPM values of many tens gram per litre. This suspension is transported up-estuary with the flood. Around high water slack, part of the suspension settles, being remixed during ebb, while migrating down-estuary, but likely not much further than Terborg. Around low water slack, a large fraction of the sediment settles, reforming the pool of fluid mud. The rapid entrainment from the fluid mud layer after low water slack is only possible when the peak flood velocity exceeds a critical value of around 1 m/s, i.e. when the stratified water column seems to become internally supercritical. If the peak flood velocity does not reach this critical value, f.i. during neap tide, fluid mud is not entrained up to the OBS sensors. Thus, it is not classical tidal asymmetry, but the peak flood velocity itself which governs the hyper-turbid state in the Lower Ems River. The crucial role of river flow and river floods is in reducing these peak flood velocities. During elongated periods of high river flow, in e.g. wintertime, SPM concentrations reduce, and the soft mud deposits consolidate and possibly become locally armoured as well by sand washed in from the river. We have no observations that sediments are washed out of the hyper-turbid zone. Down-estuary of Terborg, where SPM values do not reach hyper-turbid conditions, the SPM dynamics are governed by classical tidal asymmetry and estuarine circulation. Hence, nowhere in the river, sediments are flushed from the upper reaches of the river into the Ems-Dollard estuary during high river flow events. However, exchange of sediment between river and estuary should occur because of tide-induced dispersion.

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A laboratory study on the behavior of mud from the Western Scheldt under tidal conditions

Cited by 14 publications

References 9 publications

Repeated erosion of cohesive sediments with biofilms

Repeated erosion of cohesive sediments with biofilms

Bottom fine sediment boundary layer and transport processes at the mouth of the Changjiang Estuary, China

SPM response to tide and river flow in the hyper-turbid Ems River

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