Hydrodynamic and geomorphic controls on mouth bar evolution

Esposito, C. R.; Georgiou, Ioannis Y.; Kolker, Alexander S.

doi:10.1002/grl.50333

Cited by 55 publications

(49 citation statements)

References 22 publications

(39 reference statements)

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“…[3] Researchers have analyzed both large-scale structure of deltaic systems [Edmonds, 2012b;Edmonds et al, 2009Edmonds et al, , 2011aEdmonds et al, , 2011bEdmonds and Slingerland, 2010;Canestrelli et al, 2010, Geleynse et al, 2010, 2011Jerolmack, 2009;Jerolmack and Paola, 2007;Fagherazzi, 2008;Jerolmack and Swenson, 2007;Fagherazzi and Overeem, 2007] and their morphological units, such as mouth bars [Esposito et al, 2013;Nardin et al, 2013;Nardin and Fagherazzi, 2012;Edmonds and Slingerland, 2007;Wang, 1984;Wright, 1977;Bates, 1953].…”

Section: Introductionmentioning

confidence: 99%

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Effect of tides on mouth bar morphology and hydrodynamics

et al. 2013

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[1] Mouth bars are morphological units important for deltas, estuaries, or rivers debouching into the sea. Several processes affect the formation of these deposits. This paper focuses on the role of tides on shaping mouth bars, presenting both hydrodynamic and morphodynamic results. The effect of tides is analyzed in two end-member configurations: a river with a small tidal discharge compared to the fluvial discharge (fluvial dominated) and a river with a very large tidal discharge (tidal dominated). Mouth bar formation is analyzed using the coupled hydrodynamic and morphodynamic model Delft3D. The presence of tides influences the hydrodynamics of the jet exiting the river mouth and causes an increase in the averaged jet spreading. At low tide the lower water depth in the basin promotes a drawdown water profile in the river and an accelerated flow near the mouth. The resulting velocity field is characterized by residual currents affecting growth and final shape of the mouth bar. Simulations indicate that mouth deposits are characterized by the presence of two channels for negligible tidal discharge, whereas three principal channels are present in the tidal-dominated case, with a central channel typical of tidal inlets. On the basis of our numerical analyses, we present a robust criterion for the occurrence of mouth deposits with three channels. Trifurcations form when the tidal discharge is large with respect to the fluvial one and the tidal amplitude is small compared to the water depth. Finally, predicted mouth bar morphologies are compared with good agreement to river mouths in the Gulf of Mexico, USA.

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Section: Introductionmentioning

confidence: 99%

“…Esposito et al [2013] successfully tested Edmonds and Slingerland [2007] model for mouth bar evolution by means of field data near the mouth of the Mississippi River.…”

Section: Introductionmentioning

confidence: 99%

Effect of tides on mouth bar morphology and hydrodynamics

et al. 2013

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“…Importantly, the point where the channel loses definition is also near the maximum elevation in an axial transect of the channel. Although dimensions vary, this general morphology has been observed on the Wax Lake Delta (Shaw et al, 2016b;Shaw and Mohrig, 2014), Brant's Pass crevasse on the birds-foot delta of the Mississippi River (Esposito et al, 2013), the Mobile and Apalachicola river deltas (Edmonds et al, 2011b) and the St. Clair River Delta (Figure 1b; NOAA, 2017). Additionally, numerical models often produce this morphology (Caldwell and Edmonds, 2014;Geleynse et al, 2010;5 Liang et al, 2016).…”

Section: Bathymetry and Flow Patterns On River-dominated Deltasmentioning

confidence: 89%

Measuring Subaqueous Progradation of the Wax Lake Delta with a Model of Flow Direction Divergence

Shaw¹,

Estep²,

Whaling³

et al. 2018

Preprint

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Abstract.Remotely sensed flow patterns can reveal the location of the subaqueous distal tip of a distributary channel on a prograding river delta. Morphodynamic feedbacks produce distributary channel tips that become shallower over their final reaches before becoming deeper over the unchannelized foreset. The flow direction field over this morphology tends to diverge 10 and then converge providing a diagnostic signature that can be captured in flow or remote sensing data. Twenty-one measurements from the Wax Lake Delta (WLD) in coastal Louisiana, and 317 measurements from numerically simulated deltas show that the transition from divergence to convergence occurs in a distribution that is centered just downstream of the channel tip, on average 132 m in the case of the WLD. With these data we validate the Flow Direction to Channel tips (FD2C) inverse model for remotely estimating subaqueous channel tip location. We apply this model to 33 remotely sensed images of 15 the WLD between its initiation in 1974 and 2016. We find that the distributaries grew unevenly, 6 of the primary channels grew at rates of 60-80 m/yr while one grew at 116 m/yr. We also estimate the growth rate of the total area enclosed by the subaqueous delta platform to be 1.83 km 2 /yr with no obvious rate changes over time.

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“…The closest two existing analogs for sediment diversion in coastal Louisiana (West Bay Diversion and Wax Lake Outlet) both discharge into water bodies with depths that typically range from 1 to 3 m [39,40], whereas the Mid-Barataria Sediment Diversion will empty into an area consisting of broken, degraded marsh and shallow, open water before reaching Barataria Bay (2 m water depth) [41]. Wetlands in existing diversions and diversion analogue settings, such as the West Bay Mississippi River Diversion and the Cubit's Gap Delta can accrete 1-5 cm of sediment during a seasonal flood pulse, enough to match or offset regional rates of relative sea-level rise in many locations [39,42]. Although the basin has an existing network of natural and man-made channels, it does not currently have the delta channels or distributary channel system to efficiently convey 2100 m 3 /s of water and sediment through the basin [40].…”

Section: Geology and Hydrodynamicsmentioning

confidence: 99%

Optimizing Sediment Diversion Operations: Working Group Recommendations for Integrating Complex Ecological and Social Landscape Interactions

Peyronnin

Caffey

Cowan

et al. 2017

Water

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Future conditions of coastal Louisiana are highly uncertain due to the dynamic nature of deltas, climate change, tropical storms, and human reliance on natural resources and ecosystem services. Managing a system in which natural and socio-economic components are highly integrated is inherently difficult. Sediment diversions are a unique restoration tool that would reconnect the Mississippi River to its deltaic plain to build and sustain land. Diversions are innately adaptable as operations can be modified over time. An expert working group was formed to explore how various operational strategies may affect the complex interactions of coastal Louisiana's ecological and social landscape and provide preliminary recommendations for further consideration and research. For example, initial operations should be gradually increased over 5 to 10 years to facilitate the development of a distributary channel network, reduce flood risk potential to communities, limit erosion of adjacent marshes and reduce stress to vegetation and fish and wildlife species. Diversions should operate over winter peaks to capture the highest sediment concentration, reduce vegetation loss while dormant, and reduce detrimental effects to fish and wildlife. Operations during the spring/summer should occur over shorter periods to capture the highest sediment load during the rising limb of the flood peak and minimize impacts to the ecosystem. Operational strategies should strive to build and sustain as much of the coastal landscape as possible while also balancing the ecosystem and community needs.

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Hydrodynamic and geomorphic controls on mouth bar evolution

Cited by 55 publications

References 22 publications

Effect of tides on mouth bar morphology and hydrodynamics

Effect of tides on mouth bar morphology and hydrodynamics

Measuring Subaqueous Progradation of the Wax Lake Delta with a Model of Flow Direction Divergence

Optimizing Sediment Diversion Operations: Working Group Recommendations for Integrating Complex Ecological and Social Landscape Interactions

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