Intertidal Creeks and Overmarsh Circulation in a Small Salt Marsh Basin

Abstract

The role of intertidal creek networks in overmarsh circulation is not well constrained. In this study, we systematically remove intertidal creeks from a high‐resolution salt marsh digital elevation model and conduct new flow simulations with each iteration. Overall, removal of first‐ and second‐order creeks reduced drainage density by 65%, and this had a negligible effect on overmarsh circulation and tracer distribution. However, upon removal of third‐ and fourth‐order creeks, drainage density was reduced by 80% of the original value, and changes in peak velocity magnitude across various spatial and temporal scales reveal a system‐wide switch from ebb to flood dominance. This response coincides with the interruption of topographically connected creeks that facilitate the direct exchange of water and tracer between the marsh interior and the larger subtidal system. Further, this reduction in hydraulic connectivity gives rise to less expansive tracer dispersal and a systematic decline in tracer residence time. Together, these results reveal that for the Groves Creek marsh, lower‐order intertidal creeks have a minor role in overmarsh circulation, while higher‐order creeks increase the potential for short circuiting of flow; they greatly influence overall flood and ebb dominance, and net tracer dispersal and associated retention time. Results reported here provide new insight on, for example, salt marsh restoration and the requisite digital elevation model bathymetry for robust simulations of overmarsh circulation.

Real-time coastal flood hazard assessment using DEM-based hydrogeomorphic classifiers

“…We use the 2019 Delft3D FM suite package (Delft3D Flexible Mesh Suite, 2019) to model the complex riverine, estuarine, and intertidal flat hydrodynamics in the Savannah River delta and wetland regions. The suite package has been used with satisfactory results in similar coastal studies characterized by vast wetland regions (Fagherazzi et al, 2014;Kumbier et al, 2018;Sullivan et al, 2019). Moreover, the model developed for the Savannah has been used in other studies to simulate extreme and non-extreme events including Hurricane Matthew, which hit the southeast Atlantic coast in October 2016 (Muñoz et al, 2021(Muñoz et al, , 2020.…”

Morphological evolution of creek networks in 10 restored coastal wetlands in the UK

“…The algorithm therefore allows the extraction of a systematic dataset that is comparable and can be produced quickly across multiple sites and years. Finally, it is well suited for the comparison of creek evolution in non-engineered and highly engineered sites, where creeks shaped by human intervention are poorly detected by the flow accumulation method 42 . A summary of the data types and processing protocols used in this study is provided in Table 2 .…”

Predicting dissolved organic carbon concentration in a dynamic salt marsh creek via machine learning

“…DOC estimation was performed in Groves Creek (Fig. 1), a tidal creek draining a 1.4 km 2 semi‐enclosed salt marsh (Sullivan et al 2019) in Savannah, Georgia on the east side of Skidaway Island (31°58′N 81°01′W; Blanton et al 2010). Groves Creek acts as a representative salt marsh and drainage creek system on the Georgia coast, a coast that holds one‐third of the eastern U.S. saltmarshes (Reimold 1977).…”

“…Groves Creek acts as a representative salt marsh and drainage creek system on the Georgia coast, a coast that holds one‐third of the eastern U.S. saltmarshes (Reimold 1977). Additionally, Groves Creek is a well‐studied site (Blanton et al 2010; Alexander 2015; Sullivan et al 2015, 2019) with known optical challenges influencing DOC. Such optical challenges include having relatively low CDOM (Cao et al 2018) from low freshwater (high CDOM) input, variable nutrients (Bittar et al 2016), and a particle load that impacts water color (Blanton and Atkinson 1983).…”