Influence of storm surges and sea level on shallow tidal basin erosive processes

Mariotti, G.; Fagherazzi, Sergio; Wiberg, P. L.; McGlathery, K. J.; Carniello, Luca; Defina, Andrea

doi:10.1029/2009jc005892

Cited by 119 publications

(132 citation statements)

References 41 publications

(72 reference statements)

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“…We therefore develop a simple dynamic model that includes the following processes: (i) wave power and related marsh boundary erosion increases with tidal flat fetch and depth; (ii) marsh boundary erosion increases the fetch of the adjacent tidal flats, thus increasing wave power (1,14); (iii) marsh boundary erosion releases sediments that become available to settle on the tidal flats, reducing water depths and thus decreasing wave power (1,14,15); (iv) fetch and depth control sediment resuspension by waves on the tidal flat. This resuspension mechanism, combined with tidal fluxes, determines the sediment exchange with the open sea and whether the tidal flat erodes or aggrades in time (16).…”

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confidence: 99%

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise

Mariotti

Fagherazzi

2013

Proc. Natl. Acad. Sci. U.S.A.

245

272

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High rates of wave-induced erosion along salt marsh boundaries challenge the idea that marsh survival is dictated by the competition between vertical sediment accretion and relative sea-level rise. Because waves pounding marshes are often locally generated in enclosed basins, the depth and width of surrounding tidal flats have a pivoting control on marsh erosion. Here, we show the existence of a threshold width for tidal flats bordering salt marshes. Once this threshold is exceeded, irreversible marsh erosion takes place even in the absence of sea-level rise. This catastrophic collapse occurs because of the positive feedbacks among tidal flat widening by wave-induced marsh erosion, tidal flat deepening driven by wave bed shear stress, and local wind wave generation. The threshold width is determined by analyzing the 50-y evolution of 54 marsh basins along the US Atlantic Coast. The presence of a critical basin width is predicted by a dynamic model that accounts for both horizontal marsh migration and vertical adjustment of marshes and tidal flats. Variability in sediment supply, rather than in relative sea-level rise or wind regime, explains the different critical width, and hence erosion vulnerability, found at different sites. We conclude that sediment starvation of coastlines produced by river dredging and damming is a major anthropogenic driver of marsh loss at the study sites and generates effects at least comparable to the accelerating sea-level rise due to global warming.salt marsh boundary erosion | wave erosion W ave-induced boundary erosion is a leading process threatening salt marshes (1, 2), but it is remarkably unexplored compared with the vertical dynamics of the marsh platform (3, 4). Wave-induced boundary erosion is particularly relevant along coastlines with limited subsidence such as the Mid-Atlantic coast of the United States, where large marsh areas are deteriorating (5, 6) despite marsh accretion keeping pace with contemporary rates of sea-level rise (7,8). Here, we focus on the evolution of three salt marsh sites on the US Atlantic Coast, subjected to different rates of wave-induced boundary erosion: Cape May, NJ, Virginia Coast Reserve, VA, and Charleston Sound, SC (Fig. 1). All sites are characterized by barrier islands sheltering shallow bays with extensive salt marshes and tidal flats. The bays are connected to the open sea by multiple inlets, experience limited direct riverine inputs (9, 10), and are subject to similar wind conditions (SI Text). Relative sea-level rise (RSLR) is on the order of 2 mm/y and tidal range of ∼1.4 m (SI Text). These embayments are characterized by rounded tidal flats surrounded by salt marshes, which are referred to as marsh basins (11,12).Stevenson et al. (13) reported loss of brackish marshes driven by the enlargement of marsh basins, referred to by the authors as ponds. They suggested the existence of a pond threshold width that, once exceeded, leads to ponds widening by wave-induced boundary erosion. Here, we expand this idea by (i) developing a physical...

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confidence: 99%

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise

Mariotti

Fagherazzi

2013

Proc. Natl. Acad. Sci. U.S.A.

245

272

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“…Wave-energy flux is the most often investigated factor affecting erosion rates and found to be significantly related with erosion rate in many cases (Dalrymple, 1986;Gelinas and Qidgley, 1973;Marani et al, 2011;Mariotti et al, 2010;Mcloughlin et al, 2015;Ronald and Douglas, 2005;Schwimmer, 2001), although other studies have observed a lack of significant relationships between the wave-energy flux (or wave power) and shoreline erosion rates at local and low-wave-energy shorelines (Cowart et al, 2010;Ravens et al, 2009), The regression equation that Schwimmer (2001) found is…”

Section: Wave Power Versus Erosion Ratesmentioning

confidence: 89%

Influences of Wave Climate and Sea Level on Shoreline Erosion Rates in the Maryland Chesapeake Bay

Jia

2017

Estuaries and Coasts

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SWAN and a parametric wave model implemented by the Chesapeake Bay Program(CBP) were used to simulate wave climate from 1985 to 2005 in Chesapeake Bay (CB).Calibrated sea level simulations from the CBP hydrodynamic model were acquired.Spatial patterns of sea levels during high wave events were dominated by local northsouth winds in the upper Bay and by remote coastal forcing in the lower Bay. A dataset comprising shoreline erosion rates and related characteristics was combined with the wave and sea-level climates to explore the most influential factors affecting erosion. The results show that wave power is the most significant factor for erosion in the Maryland CB. Marsh shorelines present a nearly linear relationship between wave power and erosion rates, whereas bank shorelines are less clear. The results of this study are applicable at large scales. A more comprehensive data set is needed for building detailed local predictive relationships.

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“…Lateral marsh scarp boundary movement is a complex function of waves, sediment transport and deposition, vegetation, wind, and tidal oscillation [69]. Although established vegetation is helpful for edge stabilization during gradual sea-level and tidal changes, soil type is a greater contributor to stability in more extreme events, such as breaking waves [70].…”

Section: Edge Erosionmentioning

confidence: 99%

Remote Sensing for Wetland Mapping and Historical Change Detection at the Nisqually River Delta

et al. 2017

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Coastal wetlands are important ecosystems for carbon storage and coastal resilience to climate change and sea-level rise. As such, changes in wetland habitat types can also impact ecosystem functions. Our goal was to quantify historical vegetation change within the Nisqually River watershed relevant to carbon storage, wildlife habitat, and wetland sustainability, and identify watershed-scale anthropogenic and hydrodynamic drivers of these changes. To achieve this, we produced time-series classifications of habitat, photosynthetic pathway functional types and species in the Nisqually River Delta for the years 1957, 1980, and 2015. Using an object-oriented approach, we performed a hierarchical classification on historical and current imagery to identify change within the watershed and wetland ecosystems. We found a 188.4 ha (79%) increase in emergent marsh wetland within the Nisqually River Delta between 1957 and 2015 as a result of restoration efforts that occurred in several phases through 2009. Despite these wetland gains, a total of 83.1 ha (35%) of marsh was lost between 1957 and 2015, particularly in areas near the Nisqually River mouth due to erosion and shifting river channels, resulting in a net wetland gain of 105.4 ha (44%). We found the trajectory of wetland recovery coincided with previous studies, demonstrating the role of remote sensing for historical wetland change detection as well as future coastal wetland monitoring.

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Influence of storm surges and sea level on shallow tidal basin erosive processes

Cited by 119 publications

References 41 publications

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise

Critical width of tidal flats triggers marsh collapse in the absence of sea-level rise

Influences of Wave Climate and Sea Level on Shoreline Erosion Rates in the Maryland Chesapeake Bay

Remote Sensing for Wetland Mapping and Historical Change Detection at the Nisqually River Delta

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