Ship Shoal has been a high-priority target sand resource for dredging activities to restore the eroding barrier islands in LA, USA. The Caminada and Raccoon Island pits were dredged on and near Ship Shoal, which resulted in a mixed texture environment with the redistribution of cohesive mud and noncohesive sand. However, there is very limited knowledge about the source and transport process of suspended muddy sediments near Ship Shoal. The objective of this study is to apply the Regional Ocean Modeling System (ROMS) model to quantify the sediment sources and relative contribution of fluvial sediments with the estuary and shelf sediments delivered to Ship Shoal. The model results showed that suspended mud from the Atchafalaya River can transport and bypass Ship Shoal. Only a minimal amount of suspended mud from the Atchafalaya River can be delivered to Ship Shoal in a one-year time scale. Additionally, suspended mud from the inner shelf could be transported cross Ship Shoal and generate a thin mud layer, which is also considered as the primary sediment source infilling the dredge pits near Ship Shoal. Two hurricanes and one tropical storm during the year 2017–2018 changed the direction of the sediment transport flux near Ship Shoal and contributed to the pit infilling (less than 10% for this specific period). Our model also captured that the bottom sediment concentration in the Raccoon Island pit was relatively higher than the one in Caminada in the same period. Suspended mud sediment from the river, inner shelf, and bay can bypass or transport and deposit in the Caminada pit and Raccoon Island pit, which showed that the Caminada pit and Raccoon Island pits would not be considered as a renewable borrow area for future sand dredging activities for coastal restoration.

中文翻译：

---

用于路易斯安那大陆架海岸修复的船浅滩附近的沉积物运输：2017-2018 年模型估计

Ship Shoal 一直是用于疏浚活动以恢复美国洛杉矶被侵蚀的障壁岛的高度优先目标砂资源。Caminada 和 Raccoon Island 坑在 Ship Shoal 及其附近进行疏浚，导致具有粘性泥浆和非粘性沙子重新分布的混合质地环境。然而，关于船浅滩附近悬浮泥质沉积物的来源和运移过程的知识非常有限。本研究的目的是应用区域海洋建模系统 (ROMS) 模型来量化沉积物来源和河流沉积物与输送到船浅的河口和陆架沉积物的相对贡献。模型结果表明，来自阿查法拉亚河的悬浮泥浆可以运输和绕过船浅滩。在一年的时间尺度内，只能将来自 Atchafalaya 河的极少量悬浮泥浆输送到 Ship Shoal。此外，内陆架的悬浮泥浆可通过船滩运输并产生薄泥层，这也被认为是填充船滩附近疏浚坑的主要沉积物来源。2017-2018 年的两次飓风和一次热带风暴改变了船浅滩附近沉积物输送通量的方向，并促成了坑的充填（该特定时期小于 10%）。我们的模型还捕捉到浣熊岛坑的底部沉积物浓度相对高于同期的卡米纳达。来自河流、内陆架和海湾的悬浮泥沙可以绕过或运输并沉积在卡米纳达坑和浣熊岛坑中，