Velocity variations in salt marsh creeks, Norfolk, England

Healey, Roberta; Pye, Kenneth; Stoddart, D. R.; Bayliss‐Smith, Tim

doi:10.1016/s0302-3524(81)80056-4

Cited by 67 publications

(56 citation statements)

References 3 publications

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“…Similarly, the ebb surge takes place after the drainage of the marsh for a water elevation just below the marsh surface, and it is therefore confined in the channels (Figure 3). The stage-discharge and stage-velocity curves therefore present an asymmetry as observed in the field by many researchers (Pethick 1980;Healey et al 1981).…”

Section: Fluxes Of Watermentioning

confidence: 73%

“…This model implies that when there is a sharp increase in flooded area A, the discharge surges because more water is needed to flood a larger surface (or more water must be removed to drain it; see Figure 1B result, two distinct surges are occurring in the channels, one when the marsh platform is first flooded and one when the marsh platform is drained. These surges have been measured in salt marsh channels by several authors (Myrick and Leopold 1963;Bayliss-Smith et al 1978;Healey et al 1981;French and Stoddart 1992). However, the static model implies that the water is instantaneously delivered to the entire marsh, when in reality it takes a finite time to reach each marsh location, depending on the travel path both within the channels and on the marsh platform.…”

Section: Fluxes Of Watermentioning

confidence: 99%

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Fluxes of water, sediments, and biogeochemical compounds in salt marshes

et al. 2013

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Tidal oscillations systematically flood salt marshes, transporting water, sediments, organic matter, and biogeochemical elements such as silica. Here we present a review of recent studies on these fluxes and their effects on both ecosystem functioning and morphological evolution of salt marshes. We reexamine a simplified model for the computation of water fluxes in salt marshes that captures the asymmetry in discharge between flood and ebb. We discuss the role of storm conditions on sediment fluxes both in tidal channels and on the marsh platform. We present recent methods and field instruments for the measurement of fluxes of organic matter. These methods will provide long-term data sets with fine temporal resolution that will help scientists to close the carbon budget in salt marshes. Finally, the main processes controlling fluxes of biogenic and dissolved silica in salt marshes are explained, with particular emphasis on the uptake by marsh macrophytes and diatoms.

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Section: Fluxes Of Watermentioning

confidence: 73%

Section: Fluxes Of Watermentioning

confidence: 99%

Fluxes of water, sediments, and biogeochemical compounds in salt marshes

et al. 2013

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“…As observed by BaylissSmith et al (1979), Leopold et al (1993), Myrick and Leopold (1963), Healey et al (1981) and Green et al (1986), the two velocity peaks are not identical and occur at different water stages, producing the characteristic velocity asymmetry. This velocity asymmetry is a direct consequence of over-marsh flow, with a flood peak occurring for water elevation higher than the marsh surface and ebb peak for water depths below bankfull (BaylissSmith et al, 1979;Healey et al, 1981;Green et al, 1986). The velocity asymmetry is ascribed to a sudden increase in tidal prism as the marsh surface is flooded, and to flow convergence to the creek during ebb (BaylissSmith et al, 1979).…”

Section: Introductionmentioning

confidence: 82%

“…Moreover, differential resistance coefficients for the channel and over-marsh portions of the flow attenuate the transient above-bankfull stage (French and Stoddart, 1992) favouring a shorter slack near high water and ebb dominance (Friedrichs and Perry, 2001). Often the ebb velocity exceeds the flood velocity (BaylissSmith et al, 1979;Leopold et al, 1993;Myrick and Leopold, 1963;Healey et al, 1981;Green et al, 1986), but this is not a strict rule, since several tidal channels are flood-dominated particularly when the corresponding marsh areas are limited (Ayles and Lapointe, 1996). In other cases peak flooding currents are, on average, stronger than ebb currents, but with peak ebb velocities maintained for a longer period of time (Leonard et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

The effect of bidirectional flow on tidal channel planforms

Fagherazzi¹,

Gabet²,

Furbish³

2004

Earth Surf Processes Landf

113

104

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Salt marsh tidal channels are highly sinuous. For this project, field surveys and aerial photographs were used to characterize the planform of tidal channels at China Camp Marsh in the San Francisco Bay, California. To model the planform evolution, we assume that the topographic curvature of the channel centreline is a key element driving meander migration. Extraction of curvature data from a planimetric survey, however, presents certain problems because simple calculations based on equally distanced points on the channel axis produce numerical noise that pollutes the final curvature data. We found that a spline interpolation and a polynomial fit to the survey data provided us with a robust means of calculating channel curvature. The curvature calculations, combined with data from numerous cross-sections along the tidal channel, were used to parameterize a computer model. With this model, based on recent theoretical work, the relationship between planform shape and meander migration as well as the consequences of bidirectional flow on planform evolution have been investigated. Bank failure in vegetated salt marsh channels is characterized by slump blocks that persist in the channel for several years. It is therefore possible to identify reaches of active bank erosion and test model predictions. Our results suggest that the geometry and evolution of meanders at China Camp Marsh, California, reflect the ebb-dominated regime.

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“…Later on, observations in fair weather indicated that well-defined velocity surges also occur during almost every tidal cycle in lower tidal channels Nowacki and Ogston, 2013). Continuity arguments were used to explain this phenomenon (Boon, 1975;Bayliss-Smith et al, 1979;Pethick, 1980;Healey et al, 1981;Wang et al, 1999). Nowacki and Ogston (2013) deepened the theory and suggested that maintenance of continuity produces the velocity pulse, and the pulse magnitude is determined by tidal range.…”

Section: Introductionmentioning

confidence: 99%

Velocity and sediment surge: What do we see at times of very shallow water on intertidal mudflats?

Zhang

Gong

Zhang

et al. 2016

Continental Shelf Research

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A self-designed "bottom boundary layer hydrodynamic and suspended sediment concentration (SSC) measuring system" was built to observe the hy- large vertical velocity gradient and a "surge" feature. We conclude that the very shallow water stages are transient and may not contribute much to the whole water and sediment transport, while they can play a significant role in the formation and evolution of micro-topographies on tidal flats.

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Velocity variations in salt marsh creeks, Norfolk, England

Cited by 67 publications

References 3 publications

Fluxes of water, sediments, and biogeochemical compounds in salt marshes

Fluxes of water, sediments, and biogeochemical compounds in salt marshes

The effect of bidirectional flow on tidal channel planforms

Velocity and sediment surge: What do we see at times of very shallow water on intertidal mudflats?

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