The sorting tendencies for the inlet are modeled in part from 
Inman's (1949, p. 63) analysis of sorting of shallow-water sediments under 
unidirectional flow. For the particular inlet studied | gorge depth of 
6 to 9 feet (180-270 cm)] , the out-flowing current lise ft/sec. (110 
cm/sec.) at the surface| in the channel is assumed to produce a stress 
on the bottom sufficient to move all bottom material. Toward the seaward 
extremity of the inlet entrance, and laterally from its sides (Figure 
3A), we postulate a rapid decrease in the threshold velocity, producing 
the rapid decrease in mean diameter of the bottom samples. As the out- 
flowing current passes into the relatively quiescent water of the 
entrance, just shoreward of the breakers in Figure 3B, the average friction 
velocity will drop somewhat. We assume that the friction velocity in the 
waters of the inlet entrance will tend to fluctuate between the threshold 
velocity for fine and coarse sand. If this is so, the bottom samples 
will show a tendency to be rather well sorted (Inman, 1949, p. 64). 
It can be further assumed that as the outflowing current enters the 
breaker zone, the turbulence conditions are such that nearly all but the 
largest sized particles (which will have previously dropped out of sus- 
pension) will be maintained in suspension. Bottom samples here can be 
expected to be better sorted than elsewhere and the mean diameter to be 
larger than that of the surrounding samples. Figure 3C shows this 
situation schematically. Just seaward of the breakers, a rapid decrease 
in friction velocities and turbulence can be expected, and the larger 
particles that pass through the breaker zone will come to rest almost 
immediately; these larger particles will rest upon or become mixed with 
the finer particles of the beach sands of the shoaling-wave zone (Figure 
1) of the previous tide. Because progressively finer particles drop 
rapidly out of suspension in a seaward direction, sorting beyond the 
breakers will abruptly become poorer, and the poorest sorting will occur 
at a relatively short distance beyond the breakers. Sorting farther out 
into the sea will improve, but will not equal that of the breaker zone 
where it is best (Figure 1). Batten's (1962) study of the Beaufort Inlet 
sediments indicates the relatively well-sorted nature of the sediments 
in his "zone of wave action" seaward of the surf zone. The mean diameter 
of the bottom particles will decrease gradually in a seaward direction, 
as summarized in Figure 3C. 
The ultimate model to be used here provides for the wave fronts 
approaching at an angle to the shoreline, rather than parallel to it as 
in Figure 2A. The longshore current thus generated adds a final compli- 
cating feature to the model. (Figure 4A shows the relations, assuming 
moderate to low wave heights and moderate longshore-current velocity.) 
To simplify the dynamic model somewhat, we assume that the inlet outflow 
is of such velocity that it is deflected only a moderate amount by the 
longshore current (Figure 4A). Both currents will then intermix and 
become a single current in a direction dictated by simple vector addition. 
