Riverine sediment inflow to Louisiana Chenier Plain in the Northern Gulf of Mexico

Rosen, Timothy; Xu, Y. Jun

doi:10.1016/j.ecss.2011.09.013

Cited by 18 publications

(14 citation statements)

References 13 publications

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“…However, the increase should not be attributed to land use effects because the river discharge increased during the past eight years while the TP concentration in the river was relatively unchanged ( Table 5). The Vermilion River receives partial flow from the Atchafalaya River through river diversion [16] and it is not clear whether the discharge increase was caused by an increased diversion from the Atchafalaya River or an increased rainfall within the drainage area. In any case, the findings indicate the important role of river discharge in TP export.…”

Section: Flow and Rainfall Effects On Phosphorus Fluxesmentioning

confidence: 99%

“…The Mermentau River drains a land area of 16,997 km 2 with a length of 115 km [23], and discharges into the Grand Lake before reaching the NGOM. The Vermilion River is 116 km long with a basin area of 4470 km 2 [16,24], draining into the Vermilion Bay. Except for some navigational locks, no dams were constructed along the main channels of these two rivers.…”

Section: Introductionmentioning

confidence: 99%

“…Land use conditions are different among the three river basins. The Mermentau and Vermilion River Basins are dominated much more by agricultural land uses (67% and 61%, respectively) when compared with the Calcasieu River Basin (26%) [16,[25][26][27]. The difference in land use dominance may have profound effects on nutrient input from the river basins.…”

Section: Introductionmentioning

confidence: 99%

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Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

2018

Water

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This study aims to evaluate recent total phosphorus (TP) and dissolved inorganic phosphorus (DIP) transport from three coastal rivers-the Calcasieu, Mermentau, and Vermilion Rivers-that drain watersheds with varied agriculture intensities (21%, 67%, and 61%, respectively) into the northern Gulf of Mexico, one of the world's largest summer hypoxic zones. The study also examined the spatial trends of TP and DIP from freshwater to saltwater along an 88-km estuarine reach with salinity increasing from 0.02 to 29.50. The results showed that from 1990-2009 to 2010-2017, the TP fluxes for one of the agriculture-intensive rivers increased while no significant change was found for the other two rivers. Change in river discharge was the main reason for this TP flux trend. The two more agriculture-intensive river basins showed consistently higher TP and DIP concentrations and fluxes, as well as higher DIP:TP ratios than the river draining less agriculture-intensive land, confirming the strong effect of land uses on phosphorus input and speciation. Longitudinal profiles of DIP along the salinity gradient of the estuarine reach displayed characteristic input behavior. Desorption of DIP from suspended solids and river bed sediments, urban inputs, as well as stronger calcium carbonate and phosphorus co-precipitation at the marine endmember could be the reasons for such mixing dynamics.

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Section: Flow and Rainfall Effects On Phosphorus Fluxesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

2018

Water

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“…1), although ridge morphology near river mouths show clear signs of local reversal due to ebb-tidal estuarine interactions (McBride et al, 2007). Four small rivers dissect the CP (Rosen and Xu, 2011): Sabine River (average discharge of 219 m 3 s −1 ), Calcasieu River (72 m 3 s −1 ), Mermenteau River (82 m 3 s −1 ) and Vermillion River (33 m 3 s −1 ). The mean tidal range is on the order of 0.3-0.4 m and is unlikely to have seen much change over the time window of interest to the present study (Hill et al, 2011).…”

Section: ± 082mentioning

confidence: 99%

“…During the past 0.5 ka the mass accumulation rates for the CP were slightly negative on average. Local rivers (Calcasieu, Mermentau, Vermillion) transport a negligible 0.13 Mt yr −1 (Rosen and Xu, 2011) that is probably mostly trapped within the CP. To study the evolution of different portions of the CP we calculated mass accumulation rates for four coastal segments (Fig.…”

Section: Chenier Plainmentioning

confidence: 99%

Late Holocene evolution of a coupled, mud-dominated delta plain–chenier plain system, coastal Louisiana, USA

Hijma

Shen

Törnqvist³

et al. 2017

Earth Surf. Dynam.

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Abstract. Major deltas and their adjacent coastal plains are commonly linked by means of coast-parallel fluxes of water, sediment, and nutrients. Observations of the evolution of these interlinked systems over centennial to millennial timescales are essential to understand the interaction between point sources of sediment discharge (i.e. deltaic distributaries) and adjacent coastal plains across large spatial (i.e. hundreds of kilometres) scales. This information is needed to constrain future generations of numerical models to predict coastal evolution in relation to climate change and other human activities. Here we examine the coastal plain (Chenier Plain, CP) adjacent to the Mississippi River delta, one of the world's largest deltas. We use a refined chronology based on 22 new optically stimulated luminescence and 22 new radiocarbon ages to test the hypothesis that cyclic Mississippi subdelta shifting has influenced the evolution of the adjacent CP. We show that over the past 3 kyr, accumulation rates in the CP were generally 0-1 Mt yr −1 . However, between 1.2 and 0.5 ka, when the Mississippi River shifted to a position more proximal to the CP, these rates increased to 2.9 ±1.1 Mt yr −1 or 0.5-1.5 % of the total sediment load of the Mississippi River. We conclude that CP evolution during the past 3 kyr was partly a direct consequence of shifting subdeltas, in addition to changing regional sediment sources and modest rates of relative sea-level (RSL) rise. The RSL history of the CP during this time period was constrained by new limiting data points from the base of overwash deposits associated with the cheniers.These findings have implications for Mississippi River sediment diversions that are currently being planned to restore portions of this vulnerable coast. Only if such diversions are located in the western portion of the Mississippi Delta plain could they potentially contribute to sustaining the CP shoreline. Our findings highlight the importance of a better understanding of mud-dominated shorelines that are often associated with major deltas, in light of the enormous investments in coastal management and restoration that will likely be made around the globe, now and especially later during this century.

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Chenier Formation Through Wave Winnowing and Tidal Transport

Tas

Maren

Reniers

2022

Preprint

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Cheniers are ridges consisting of coarse-grained sediments, resting on top of the fine sediment that forms the otherwise muddy coast. In this paper, we use Delft3D to explore how cheniers are formed through wave winnowing. We identify three phases of chenier development: (1) a winnowing phase, during which mud is washed out of the seabed initially consisting of a mixture of sand and mud, (2) a sand transport phase, when the sand in the upper layer is transported onshore, and (3) a crest formation phase, during which a chenier crest rapidly develops at the landward limit of onshore sediment transport. The main mechanism driving onshore sand transport is wave asymmetry. During calm conditions, sand transport takes place within a narrow band limiting the volume of sand delivered nearshore, and therefore no chenier develops. In contrast, average storm conditions mobilise sufficient sand for a crest to develop. Our results thus reveal that chenier formation through wave winnowing does not require extreme storm conditions. Furthermore, our study showed that chenier formation through wave winnowing is a relatively slow process, with the largest time scales associated with the winnowing and sand transport. Once sufficient sand is available nearshore, the crest develops rapidly.

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Riverine sediment inflow to Louisiana Chenier Plain in the Northern Gulf of Mexico

Cited by 18 publications

References 13 publications

Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

Phosphorus Fluxes from Three Coastal Watersheds under Varied Agriculture Intensities to the Northern Gulf of Mexico

Late Holocene evolution of a coupled, mud-dominated delta plain–chenier plain system, coastal Louisiana, USA

Chenier Formation Through Wave Winnowing and Tidal Transport

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