| Near-bed hydrodynamics, sediment suspension, erosion, and deposition were investigated in tidal channels, on a tidal flat, and in man-made ditches within tidal marshes. Highly-resolved velocity profiles were measured in the lower 0.03 m of the water column in small tidal channels using acoustic Doppler profiling velocimeters. Shear stresses and turbulent kinetic energy followed a similar trend with the largest peaks during ebb tide. The shear stress during flood tide was on average approximately 30 % of the shear stress during ebb tide. Turbulence production exceeded turbulence dissipation at every phase of the tide, suggesting that advection and vertical diffusion are not negligible.;Data collected in small tidal channels intersecting a tidal flat indicated that the channel velocity peaked when the water level was near the tidal flat level. In the channel intersecting the tidal flat, the shear stress, turbulence, and along-channel velocity were ebb dominant. Distinct pulses in velocity occurred when the water level was near the tidal flat level. Water levels were elevated during a storm event, during which velocities, turbulent kinetic energy and shear stress were smaller than during normal conditions. Long-wave infrared imagery of the tidal mud flat was used to estimate flat elevations. Traditional surveying methods are difficult to use on soft mud flats. The approach utilizes identification of the intersection of water with the surface of the mud flat through a rising tide. Elevation estimates showed excellent agreement (absolute error generally less than 0.02 m) with ground truth elevations.;Near-bed velocity, sediment concentration, and bed level change were measured over a 3-week period in man-made ditches that are prevalent throughout tidal marshes along the Atlantic US coast. Velocities in the main channel were ebb dominant and peaked at a lower water depth during ebb tide than during flood tide. Velocity and shear stress were maximum during a storm event. The bed accreted at the most landward sites, while it eroded closer to the canal during the experiment. At all sites, erosion occurred during the accelerating phase of the flood tide, and accretion of a similar magnitude occurred during the decelerating phase of the ebb tide. |
