Classification of clastic coastal depositional environments

Boyd, Ron; Dalrymple, Robert W.; Zaitlin, Brian A.

doi:10.1016/0037-0738(92)90037-r

Cited by 517 publications

(327 citation statements)

References 17 publications

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“…An expanded version of this classification system includes all coastal environments in which larger river influence leads to delta development and low or absent river influence leads to lagoons, strandplains and tidal flats Boyd et al, 1992). Qualitatively our results also show that for higher river discharge the estuarine system transitions to a deltaic system (Fig.…”

Section: Transition From Estuary To Deltasupporting

confidence: 63%

“…We observe similar behaviour in the model scenarios but here this is related not merely to grain size but to the supply rate. Alternatively, Dalrymple et al (1992) and Boyd et al (1992) developed a classification system with a fourth dimension based on the evolution of coastal systems by defining it as a progradating or transgressive system on the basis of sea level rise and sediment supply. This system disregards the possibility of an equilibrium without progradation and without transgression through combinations of sediment supply but otherwise similar hydrodynamic conditions.…”

Section: Transition From Estuary To Deltamentioning

confidence: 99%

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Effects of mud supply on large-scale estuary morphology and development over centuries to millennia

et al. 2017

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Abstract. Alluvial river estuaries consist largely of sand but are typically flanked by mudflats and salt marshes. The analogy with meandering rivers that are kept narrower than braided rivers by cohesive floodplain formation raises the question of how large-scale estuarine morphology and the late Holocene development of estuaries are affected by cohesive sediment. In this study we combine sand and mud transport processes and study their interaction effects on morphologically modelled estuaries on centennial to millennial timescales. The numerical modelling package Delft3D was applied in 2-DH starting from an idealised convergent estuary. The mixed sediment was modelled with an active layer and storage module with fluxes predicted by the Partheniades-Krone relations for mud and Engelund-Hansen for sand. The model was subjected to a range of idealised boundary conditions of tidal range, river discharge, waves and mud input. The model results show that mud is predominantly stored in mudflats on the side of the estuary. Marine mud supply only influences the mouth of the estuary, whereas fluvial mud is distributed along the whole estuary. Coastal waves stir up mud and remove the tendency to form muddy coastlines and the formation of mudflats in the downstream part of the estuary. Widening continues in estuaries with only sand, while mud supply leads to a narrower constant width and reduced channel and bar dynamics. This self-confinement eventually leads to a dynamic equilibrium in which lateral channel migration and mudflat expansion are balanced on average. However, for higher mud concentrations, higher discharge and low tidal amplitude, the estuary narrows and fills to become a tidal delta.

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Section: Transition From Estuary To Deltasupporting

confidence: 63%

Section: Transition From Estuary To Deltamentioning

confidence: 99%

Effects of mud supply on large-scale estuary morphology and development over centuries to millennia

et al. 2017

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“…Several studies have demonstrated a broad link between wave energy and tidal-flat morphology (Boyd et al 1992;Ryan and Cooper 1998). At a local scale, Carling (1982) investigated the role of waves by deploying a wave pole at a single location and using time-averaged results as a measure of wave intensity.…”

Section: Introductionmentioning

confidence: 99%

Relationships Between Wave-Induced Currents and Sediment Grain Size on a Sandy Tidal-Flat

Málvarez¹,

Cooper²,

Jackson³

2001

Journal of Sedimentary Research

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Studies of sedimentation on sandy tidal-flats have long acknowledged that tidal flows and waves are the most influential hydrodynamic forcing factors operating on surficial sediments. Tidal flows influence the long-term evolution of tidal-flats because of the asymmetry of tidal regimes (flood and ebb). Tidal current activity is mainly confined to channels. Outside the channels, mainly on the upper tidalflats, tidal current velocities decrease and sediment entrainment is frequently ascribed to wave action. The role of wave-induced processes on intertidal-flat sediments is frequently stated but has seldom been investigated, apparently because of methodological constraints.In this paper we report on investigations into the role of wave processes in determining surficial sediment distribution patterns on a sandy tidal-flat at Newtownards, at the northern end of Strangford Lough, Northern Ireland (spring tidal range 3.5 m). The main aim of this paper is to investigate the potential relationship between waveinduced processes and surficial sediments without attempting to achieve a comprehensive analysis of other sedimentation. The methodological approach involves numerically modeling wave propagation and comparing this with sediment distribution on a controlled field site. The method enables the role of waves on tidal-flats to be more fully assessed. Waves were modeled at a variety of tidal levels and wave data were extracted from the model grid at positions co-incident with sediment sampling locations. Multiple correlation of sediment mean grain size with simulated wave-induced orbital velocity showed a distinctive variation in correlation coefficients according to water level. The best (and statistically significant) correlations occur when water levels occupy a vertical range between Ϫ0.15 and 1.0 m local Ordnance Level (OD). In the absence of strong tidal currents, sediment distribution appears to be best explained by waves acting at these water levels.It is inferred that at lower-than-optimum water levels, wave energy is less influential on sediment texture since (1) part of the tidal-flat is still exposed and (2) the fetch over which the waves are generated is reduced. At higher-than-optimum water levels, wave energy may be sufficient to transport sediment, but the wave penetration in the column of water is not sufficient to permit wave energy dissipation at the sediment surface. Tidal currents are dominant at low tidal elevations so outside channels wave-induced currents exert most influence on the tidal-flats.

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“…Although coastal environments and associated deposits are extremely diverse, sedimentological models promote the notion that coastal deposits can be identified as wave or tide dominated based upon their sedimentary character (BOYD et al, 1992). In fact, wave and tide dominated settings are distinctive in terms of physical processes and geomorphology, which cause these two settings to develop distinctive sedimentary deposits.…”

Section: Introductionmentioning

confidence: 99%

Siltation rate and main anthropic impacts on sedimentation of the São Luís tidal inlet - State of Maranhão, Brazil

2016

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In recent decades, intense human intervention in the coastal zone has given rise to severe siltation and erosion problems. This scenario is located the São Luís tidal inlet, formed by the mouths of the Anil and Bacanga rivers which due to various kinds of interference have been changing their sediment transport and deposition processes. With these changes in mind, this study sought to evaluate the evolution of the siltation and sedimentation rates in this area, as well as the main anthropogenic influences associated with this process. The methodology consisted in verifying the morphological evolution on the basis of the scanning and vectorization of nautical charts of 1947 and 1966, bathymetric surveys conducted in 2006, and aerial photos dating from 2011. The results show a silting up process coincident with interventions that occurred in the Anil and Bacanga river basins, with a volume of silt estimated at 8.5x106 m3, over the period from 1944 to 2011 (64 years), at a rate of 1.6 cm.yr-1. These processes are associated mainly with the construction of the Bacanga dam and land reclamation projects undertaken for the purpose of providing new areas for urban expansion. The evaluation of the results showed intense and advanced silting up of the São Luís tidal inlet, at rates proportionally greater than those of other estuaries, calling for corrective actions and the implementation of coastal management policies for this area.

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Classification of clastic coastal depositional environments

Cited by 517 publications

References 17 publications

Effects of mud supply on large-scale estuary morphology and development over centuries to millennia

Effects of mud supply on large-scale estuary morphology and development over centuries to millennia

Relationships Between Wave-Induced Currents and Sediment Grain Size on a Sandy Tidal-Flat

Siltation rate and main anthropic impacts on sedimentation of the São Luís tidal inlet - State of Maranhão, Brazil

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