Document Type

Article

Publication Date

1-1-2026

Abstract

Hurricane Ida made landfall in 2021 as a category 4 over Louisiana (USA), causing massive marsh erosion (gross loss 280 km2, net loss 260 km2) in Barataria Basin, equivalent to about 32 years of marsh loss without hurricanes. Hurricane Ida erosion occurred through whole-scale marsh removal (failure mechanism), as opposed to lateral edge erosion, mostly (56%) in intermediate marshes. When considering all salinity zones, 82% of the total marsh loss occurred in marshes dominated by Sporobolus pumilus (Spartina patens), likely because these marshes were composed of semi-floating blocks, which can be easily lifted and advected away during a storm surge. Fresh marshes, despite also being floating, had a smaller marsh loss than the adjacent intermediate marshes. This is possibly due to higher soil strength or higher lateral coherence of the marsh mat. About 7% of the eroded marsh (20 km2) re-deposited immediately after Ida, mostly in the fresh region. This study highlights the susceptibility of intermediate marshes, specifically those dominated by S. pumilus, to Hurricane-driven failure. Sporobolus pumilis marshes in this area may be particularly susceptible due to its semi-floating condition with hummock-hollow topography, which likely occurs when S. pumilis is stressed. Failure erosion needs to be better understood and accounted for in predictions of marsh loss. Marsh creation in Barataria Basin (1 km2/yr since 2016) is currently unable to keep pace with marsh loss. However, created marshes are not affected by failure due to their high bulk density, and hence have a higher chance to persist in the future.

Publication Source (Journal or Book title)

Wetlands

Download

Share

COinS