The effect of changing tidal energy over the spring-neap cycle on net sediment deposition in a hypertidal Bay of Fundy salt marsh creek

Abstract

Removal of tidal energy by proposed commercial-scale tidal power installations in the Minas Passage has raised concern for a non-linear response of fine sediments in far-field environments, including salt marshes. To investigate the effects of changing tidal amplitude and energy on tidal creek processes, measurements of current velocity and suspended sediment concentration, and samples of deposited and suspended sediment, were collected in a hypertidal (tide range > 6 m) creek in the Upper Bay of Fundy over 15 tidal cycles. Current velocity and turbulence in the creek showed: (1) marked variability associated with increasing tidal amplitude, and (2) the influence of flood and ebb pulses with flooding and drainage of the marsh surface. Parameterization of disaggregated inorganic grain size (DIGS) spectra with a non-liner, least-squares fit model suggest that fluctuating net deposition over the study period (55 - 328 g·m[superscript -2]) is not directly related to changes in the flocculated nature of suspended materials, despite variation in mean floc fraction (0.67 - 0.89) and floc limit (12 - 26 [mu]m).