Through the new method for automatic extraction of a tidal network from top
ographic or bathymetric fields described in a companion paper [Fagherazzi e
t al., this issue], we analyze the morphology of aggregated patterns that w
e observe in nature in different tidal environments. Specifically, we defin
e, on the basis of a hydrodynamic analysis, a procedure for watershed delin
eation and for the identification of the "divides" for every subnetwork and
look at the resulting drainage density and its related scaling properties.
From the systematic, large-scale plots of drainage density and channel wid
th versus watershed area we address the issue of a possible geomorphic crit
erion that corresponds to the parts of the tidal landscape that are charact
erized by river-like features. We also analyze the relationship of total co
ntributing tidal basin area to channel widths and to mainstream lengths (Ha
ck's law). We study comparatively probability distributions of total draina
ge areas and of "botanical" mass (the area of the channelized landscape ups
tream of a given section) for tidal and fluvial patterns and find altered s
caling features of tidal landforms that reflect the complex interactions of
different mechanisms that shape their geometry. Simple geomorphic relation
ships of the types observed in the fluvial basin (e.g,, power laws in the w
atershed area versus drainage density, mainstream length, or channel width
relationships) do not hold throughout the range of scales investigated and
are site-specific. We conclude that tidal networks unlike rivers exhibit gr
eat diversity in their geometrical and topological forms. This diversity is
suggested to stem from the pronounced spatial gradients of landscape-formi
ng flow rates and from the imprinting of several crossovers from competing
dynamic processes.