Vegetated intertidal plains Unvegetated intertidal plains
Overbank flow
Low frequency of occurrence (only for the highest tides) Relatively shallow water depth (\(Y_{\text{MAX}}\)<1 m) Weak and frictionally-dominated flow (\(v_{\text{MAX}}=\)0.1-0.2 m/s) Flow direction nearly perpendicular to the channel-axis orientation High frequency of occurrence (almost every tidal cycle) Relatively large water depths (\(Y_{\text{MAX}}\)>3-4 m) Strong and sheet-flow-dominated flow (\(v_{\text{MAX}}>\)0.4-0.5m/s) Flow direction virtually unrelated to the channel-axis orientation
Stage-velocity relation Higher velocities for above-bankfull stages (\(Y\)>\(Y_{B}\)) Higher velocities for below-bankfull stages (\(Y\)<\(Y_{B}\))
Secondary circulations
Relatively strong More pronounced when primary streamwise flows are stronger (i.e., in phase with streamwise flows) Relatively weak More pronounced when primary flows are weaker (i.e., out of phase with streamwise flows)
Helical flow Well developed Poorly developed
Flow separation Possible as a function of bend geometry and tidal flow characteristics (i.e, Froude number) Possible as a function of bend geometry and tidal flow characteristics (i.e, Froude number)
Rainfall runoff Limited importance due to the presence of vegetation Potentially significant due to the absence of vegetation
Wave action on intertidal plains Weak due to wave attenuation by vegetation Strong due to high overbank water depths and reduced friction