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Hurricanes are one of the most devastating earth surface processes. In 2020 and 2021, Hurricanes Zeta and Ida pounded the Mississippi River Delta in two consecutive years, devastated South Louisiana, and raised tremendous concerns for scientists and stakeholders around the world. This study presents a high-resolution spatial-temporal analysis incorporating planialtimetric data acquired via LIDAR, drone, and satellite to investigate the shoreline dynamics near Port Fourchon, Louisiana, the eye of Ida at landfall, before and after the beach nourishment project and recent hurricane landfalls. The remote sensing analysis shows that the volume of the ~2 km studied beachfront was reduced by 240,858 m3 after consecutive landfalls of Hurricanes Zeta and Ida in 2020 and 2021, while 82,915 m3 of overwash fans were transported to the backbarrier areas. Overall, the studied beach front lost almost 40% of its volume in 2019, while the average dune crest height was reduced by over 1 m and the shoreline retreated ~60 m after the two hurricane strikes. Our spatial-temporal dataset suggests that the Louisiana Coastal Protection and Restoration Authority’s (CPRA’s) beach nourishment effort successfully stabilized the beach barrier at Port Fourchon during the hurricane-quiescent years but was not adequate to protect the shoreline at the Mississippi River Delta from intense hurricane landfalls. Our study supports the conclusion that, in the absence of further human intervention, Bay Champagne will likely disappear completely into the Gulf of Mexico within the next 40 years.
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Impacts of Coastal Infrastructure on Shoreline Response to Major Hurricanes in Southwest Louisiana
The Rockefeller Wildlife Refuge, located along the Chenier Plain in Southwest Louisiana, was the location of the sequential landfall of two major hurricanes in the 2020 hurricane season. To protect the rapidly retreating coastline along the Refuge, a system of breakwaters was constructed, which was partially completed by the 2020 hurricane season. Multi-institutional, multi-disciplinary rapid response deployments of wave gauges, piezometers, geotechnical measurements, vegetation sampling, and drone surveys were conducted before and after Hurricanes Laura and Delta along two transects in the Refuge; one protected by a breakwater system and one which was the natural, unprotected shoreline. Geomorphological changes were similar on both transects after Hurricane Laura, while after Delta there was higher inland sediment deposition on the natural shoreline. Floodwaters drained from the transect with breakwater protection more slowly than the natural shoreline, though topography profiles are similar, indicating a potential dampening or complex hydrodynamic interactions between the sediment—wetland—breakwater system. In addition, observations of a fluidized mud deposit in Rollover Bayou in the Refuge are presented and discussed in context of the maintenance of wetland elevation and stability in the sediment starved Chenier Plain.
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- PAR ID:
- 10341365
- Date Published:
- Journal Name:
- Frontiers in Built Environment
- Volume:
- 8
- ISSN:
- 2297-3362
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.3389/fbuil.2022.885215
