Fig. 4. Contours of slopes at Shinnecock Inlet ebb shoal, 1998 survey. Steepest regions are located along the lateral walls of the inlet channels,

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magnitudes around the 1998 configuration of the

puted from transects located in these regions ranged

from 4j to 6j. Scour holes located near jetties con-

ebb shoal at Shinnecock Inlet is displayed in Fig. 4,

tained the steepest slopes, ranging from 10j to 12j

and Fig. 5 is a cross-section of the ebb shoal at this

inlet that also illustrates notation. Typically, slopes on

(Fig. 4).

the ebb shoal and related bar features do not exceed

Ebb shoals that experience higher waves were

4 6j, and seaward slopes of the ebb shoal are 1 2j

found to exhibit steeper slopes than those dominated

steeper than landward slopes. The lateral slopes asso-

by tidal forcing and with relatively smaller waves

ciated with navigation channels shortly after dredging

(Fig. 6). The linear regression relationship between

can be greater, with maximum values ranging from 6j

the maximum slope observed on the ebb shoal and the

to 8j. For natural channels, continual reworking of

significant wave height was (R2 = 0.75):

sediment by waves and tidal current smoothes the

bebb 1:61 2:57HS

bottom and reduces fluctuations, producing milder

slopes that range from 3j to 5j. The channel slopes

where bebb is the limiting ebb-shoal slope in degrees,

decrease seaward, with magnitudes varying between

1j and 2j on the outer ebb shoal. The largest

and HS is the average-annual significant wave height

gradients (steepest slopes) associated with the periph-

in meters. Data sets collected after dredging across the

ery of the ebb-tidal shoals were usually oriented

ebb shoal (which temporarily creates steeper slopes)

Fig. 4. Contours of slopes at Shinnecock Inlet ebb shoal, 1998 survey. Steepest regions are located along the lateral walls of the inlet channels,

around the periphery of the ebb shoal, and along the shoreline.