Seasonal influences on the ecomorphodynamics of a hypertidal salt marsh and tidal creek system

Abstract

Seasonal variability in the ecomorphodynamics of a Bay of Fundy tidal creek and salt marsh was analyzed to better understand how these systems might respond to potential tidal energy extraction. Data were collected for 62 tides for deposition, sediment concentration, velocity, grain size, and vegetation at four stations from the creek thalweg to the marsh surface. Deposition rates varied spatially from 56.4 g·m[superscript -2] at the creek thalweg to 15.3 g·m[superscript -2] at the marsh surface. Deposition and erosion were both most active in late fall and winter. This seasonal change, led by higher sediment concentrations, was strongest at the creek and marsh bank. Sediments were predominantly deposited in floc form (76-83%), and grain size of both suspended and deposited material was more influenced by a large rainfall event than seasonality. Understanding the mechanism of sediment transport is crucial to anticipate changing sedimentation patterns due to anthropogenic and climatic influences.