Effects of Beach Nourishment Project on Coastal Geomorphology and Mangrove Dynamics in Southern Louisiana, USA
Effects of Beach Nourishment Project on Coastal Geomorphology and Mangrove Dynamics in Southern Louisiana, USA
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DOI：
10.3390/rs13142688
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发表时间：
2021-07-01
期刊：
影响因子：
5
通讯作者：
Dietz, Marianne
中科院分区：
文献类型：
--
作者：
Lisboa Cohen, Marcelo Cancela;Vivan de Souza, Adriana;Dietz, Marianne
与河流沉积物排放量减少和飓风活动增加相关的相对海平面（RSL）上升导致海岸线快速退缩，并威胁美国路易斯安那州富尔雄港的沿海生态系统。本研究基于 QuickBird/无人机图像（2004-2019 年）和激光雷达数据（1998-2013 年），分析了 2013 年海滩滋养项目启动前后海岸线动态对红树林（白骨壤）和沼泽的影响。1998 年至 2013 年间，海岸屏障和沙丘顶部向陆地迁移。 1998 年至 2001 年间，山脊高度有所增加，然后在 2013 年有所下降，这可能是由于飓风的影响。 1998-2013年期间，这一沙质海岸屏障的总沉积量总体呈下降趋势，导致沿4公里海岸线的湿地损失约15.6公顷。这导致沙子向陆地迁移到被白骨壤（1.08 公顷）和大米草（14.52 公顷）占据的泥泞滩涂上。然而，海滩滋养项目导致海滩屏障在2012年11月至2015年1月期间有所进展，随后在2015年1月至2019年3月期间出现相对稳定的时期。此外，2013年至2019年间，沙丘顶部高度和沉积量均有所增加。这一系列因素有利于2013年后沿后屏障环境建立和扩大红树林（3.2公顷）和盐沼（25.4公顷），使滩涂能够跟上RSL的上升步伐。然而，2017 年 10 月至 2019 年 11 月期间海滩滋养项目之后，波浪和洋流导致海岸线侵蚀，恢复了海岸线退缩的长期过程，从而威胁着湿地。
Relative sea-level (RSL) rise associated with decreased fluvial sediment discharge and increased hurricane activity have contributed to the high rate of shoreline retreat and threatened coastal ecosystems in Port Fourchon, Louisiana, USA. This study, based on QuickBird/drone images (2004-2019) and LIDAR data (1998-2013), analyzed the impacts of shoreline dynamics on mangroves (Avicennia germinans) and marshes before and after the initiation of a beach nourishment project in 2013. The coastal barrier and dune crest migrated landward between 1998 and 2013. Meanwhile, the dune crest height increased between 1998 and 2001, then decreased in 2013, probably due to hurricane impacts. The total sediment volume along this sandy coastal barrier presented an overall trend of decline in the 1998-2013 period, resulting in a wetlands loss of similar to 15.6 ha along 4 km of coastline. This has led to a landward sand migration onto muddy tidal flats occupied by Avicennia germinans (1.08 ha) and Spartina (14.52 ha). However, the beach nourishment project resulted in the advancement of the beach barrier from Nov/2012 to Jan/2015, followed by a relatively stable period between Jan/2015 and Mar/2019. Additionally, both the dune crest height and sediment volume increased between 2013 and 2019. This set of factors favored the establishment and expansion of mangroves (3.2 ha) and saltmarshes (25.4 ha) along the backbarrier environments after 2013, allowing the tidal flats to keep pace with the RSL rise. However, waves and currents caused shoreline erosion following the beach nourishment project between Oct/2017 and Nov/2019, threatening wetlands by resuming the long-term process of shoreline retreat.