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Sediment transport-based metrics of wetland stability

October 10, 2015

Despite the importance of sediment availability on wetland stability, vulnerability assessments seldom consider spatiotemporal variability of sediment transport. Models predict that the maximum rate of sea level rise a marsh can survive is proportional to suspended sediment concentration (SSC) and accretion. In contrast, we find that SSC and accretion are higher in an unstable marsh than in an adjacent stable marsh, suggesting that these metrics cannot describe wetland vulnerability. Therefore, we propose the flood/ebb SSC differential and organic-inorganic suspended sediment ratio as better vulnerability metrics. The unstable marsh favors sediment export (18 mg L−1 higher on ebb tides), while the stable marsh imports sediment (12 mg L−1 higher on flood tides). The organic-inorganic SSC ratio is 84% higher in the unstable marsh, and stable isotopes indicate a source consistent with marsh-derived material. These simple metrics scale with sediment fluxes, integrate spatiotemporal variability, and indicate sediment sources.

Publication Year 2015
Title Sediment transport-based metrics of wetland stability
DOI 10.1002/2015GL065980
Authors Neil K. Ganju, Matthew L. Kirwan, Patrick J. Dickhudt, Glenn R. Guntenspergen, Donald R. Cahoon, Kevin D. Kroeger
Publication Type Article
Publication Subtype Journal Article
Series Title Geophysical Research Letters
Index ID 70168614
Record Source USGS Publications Warehouse
USGS Organization Woods Hole Coastal and Marine Science Center