Evolution of Mid-Atlantic Coastal and Back-Barrier Estuary Environments in Response to a Hurricane: Implications for Barrier-Estuary Connectivity

Abstract

Assessments of coupled barrier island-estuary storm response are rare. Hurricane Sandy made landfall during an investigation in Barnegat Bay-Little Egg Harbor estuary that included water quality monitoring, geomorphologic characterization, and numerical modeling; this provided an opportunity to characterize the storm response of the barrier island-estuary system. Barrier island morphologic response was characterized by significant changes in shoreline position, dune elevation, and beach volume; morphologic changes within the estuary were less dramatic with a net gain of only 200,000 m 3 of sediment. When observed, estuarine deposition was adjacent to the back-barrier shoreline or collocated with maximum estuary depths. Estuarine sedimentologic changes correlated well with bed shear stresses derived from numerically simulated storm conditions, suggesting that change is linked to winnowing from elevated storm-related wave-current interactions rather than deposition. Rapid storm-related changes in estuarine water level, turbidity, and salinity were coincident with minima in island and estuarine widths, which may have influenced the location of two barrier island breaches. Barrier-estuary connectivity, or the transport of sediment from barrier island to estuary, was influenced by barrier island land use and width. Coupled assessments like this one provide critical information about storm-related coastal and estuarine sediment transport that may not be evident from investigations that consider only one component of the coastal system.

Physical response of a back‐barrier estuary to a post‐tropical cyclone

“…The northeastern region underwent the largest bathymetric change (Figures a and b) and on average was more depositional as a result of barrier overwash. Similar depositional features behind the barrier were observed in Barnegat Bay, New Jersey, after Hurricane Sandy [ Miselis et al ., ].…”

“…As a consequence, relatively large volumes of the bay are exchanged [Wong, 1986] and local wind-waves are modified [Fagherazzi and Wiberg, 2009]. Differences in water level between the bay and the ocean drive sediment transport across the submerged portions of the barrier islands [Sherwood et al, 2014], located where the barriers are relatively narrow or urbanized [Miselis et al, 2016]. In addition, (unsteady) wind and wave-current interactions may have local effects that can only be handled by appropriate numerical models [Signell et al, 1990].…”

Seagrass Impact on Sediment Exchange Between Tidal Flats and Salt Marsh, and The Sediment Budget of Shallow Bays

“…Bathymetric data were collected by using a SWATHplus-H interferometric sonar, operating at a frequency of 468 kHz, with ±1 cm accuracy (Andrews et al, 2016). Since the 1940s there have been negligible bathymetric changes with exception of areas near the jetty (Defne & Ganju, 2014) and even Hurricane Sandy did not alter estuary's bathymetry (Miselis et al, 2015). The bathymetry of the study area and historical seagrass coverages are illustrated in Figure 1, with Figure 1h illustrating an idealized test case with no seagrass.…”

Connectivity in coastal systems: Barrier island vegetation influences upland migration in a changing climate

“…Barrier island migration over time is dependent on factors such as geologic context, storm frequency and intensity, topography, and sediment availability (e.g., Miselis et al, 2016;Nebel, Trembanis, & Barber, 2012;Wernette et al, 2018). However, sub-island scale processes can influence overall patterns of island response to RSLR due to topographic-vegetation interactions (e.g., Durán & Moore, 2015;Roman & Nordstrom, 1988;Stallins & Corenblit, 2018).…”