Lidar time-series analysis of a rapidly transgressing low-lying mainland barrier (Caminada Headlands, Louisiana, USA)

“…Many intense hurricanes have affected this coast during the past decades, such as Katrina (Aug/2005, Category 3), Rita (Sep/2005, Category 3), Gustav (Sep/2008, Category 2) and Ike (Sep/2008, Category 2) [41,[68][69][70][71][72][73][74]. The decrease in dune crest heights (from 2-2.5 m to 1.1-1.3 m) between 2001 and 2013 along a 3-km of the beach barrier (Figure 5), may have been caused by the removal of beach sediments during some of these events (see also [12]). This hypothesis is supported by the landward migration of overwash fans behind the beach barrier between 2004 and 2012 (Figures 1, 4 and 8), which is typical evidence for storm surge activities [14,41,75,76].…”

Section: Dynamics Of the Backbarrier Wetlandsmentioning

confidence: 99%

“…This port is the only home-base for offshore oil terminals in the U.S., and serves as the intermodal support hub for ~90% of the Gulf of Mexico drilling and ~16% of the U.S. domestic oil and gas production [7]. However, the rapid acceleration of global sea-level rise (~3.4 mm/year at the present with an expected rise of 65 cm by 2100) has jeopardized the stability of many coastal areas around the world [8], particularly along the Mississippi River Delta, where reduced sediment supply, hurricane activity, and relative sea-level (RSL) rise have been causing shoreline retreat at an alarming rate of ~12-14 m/year [9][10][11][12][13][14][15]. Moreover, three-dimensional geospatial data indicate that the sand dunes at Caminada-Moreau Headlands were migrating inland at a pace of up to 4.4 m/year between 1998 and 2013 [12]suggesting that both the shoreline and the beach barrier were migrating landward as a response to sea-level rise and reduced sediment supply.…”

Section: Introductionmentioning

confidence: 99%

Effects of Beach Nourishment Project on Coastal Geomorphology and Mangrove Dynamics in Southern Louisiana, USA

et al. 2021

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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 ~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.

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“…Figure 4 shows the percent change in post-storm subaerial island volume as well as the percent of dunes overtopped during each storm for the area east of Katrina Cut. For storms with limited dune overtopping (storms 71, 23,155,186,95,158,4,134), higher volumes of sand were eroded in the nourishment scenario than in the no-action scenario. The wider nourished beach allowed more sand to be eroded from the beach and deposited offshore during the collision regime.…”

Section: Effects Of Individual Stormsmentioning

confidence: 99%

“…Over decadal timescales, barrier islands depend on the accumulation of overwash deposition during individual storm events to migrate landward (rollover) or seaward in response to changes in sea level. Although storms may overwash and destroy dune systems, over time, dunes can maintain volume through due to natural recovery processes [4]. If a barrier island is unable to keep pace, it may drown by flattening if the island is unable to maintain the subaerial height, narrowing if the island undergoes rapid shoreline retreat [5][6][7] or deflating (a combination of narrowing and flattening) [8].…”

Section: Introductionmentioning

confidence: 99%

Assessing the Effectiveness of Nourishment in Decadal Barrier Island Morphological Resilience

Passeri

Bilskie

Hagen

et al. 2021

Water

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Nourishment has shown to be an effective method for short-term storm protection along barrier islands and sandy beaches by reducing flooding, wave attack and erosion. However, the ability of nourishment to mitigate the effects of storms and sea level rise (SLR) and improve coastal resilience over decadal time scales is not well understood. This study uses integrated models of storm-driven hydrodynamics, morphodynamics and post-storm dune recovery to assess the effectiveness of beach and dune nourishment on barrier island morphological resilience over a 30-year period, accounting for storms and a moderate amount of SLR. Results show that at the end of the 30 years, nourishment contributes to maintaining island volumes by increasing barrier height and width compared with a no-action scenario (i.e., no nourishment, only natural recovery). During storms where the collision regime was dominant, higher volumes of sand were lost from the wider beach in the nourishment scenario than in the no-action scenario. During stronger storms, nourishment reduced dune overtopping compared with the no-action scenario, allowing the island to maintain height and width. Additionally, nourishment was particularly effective in reducing breaching during back-to-back storms occurring in the same year.

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Lidar time-series analysis of a rapidly transgressing low-lying mainland barrier (Caminada Headlands, Louisiana, USA)

Cited by 16 publications

References 55 publications

A timely method for post-disaster assessment and coastal landscape survey using drone and satellite imagery

A timely method for post-disaster assessment and coastal landscape survey using drone and satellite imagery

Effects of Beach Nourishment Project on Coastal Geomorphology and Mangrove Dynamics in Southern Louisiana, USA

Assessing the Effectiveness of Nourishment in Decadal Barrier Island Morphological Resilience

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