F.S. Buonaiuto, N.C. Kraus / Coastal Engineering 48 (2003) 5165

63

Fig. 10. Linear regression between the depth over crest of an ebb shoal and the product of significant wave height and tidal prism as (HSP)1/4.

slopes along the ebb shoal, occurring on the seaward

As a final consideration, because Eq. (5) has a

periphery, are on the order of 4j. Wave-dominated

small intercept, a power law fit with the quantity HSP

was performed to yield:

environments sustain steeper slopes than tidally domi-

nated regimes.

hC 0:0424HSP0:254

MLLW

6

Almost equal predictive capability among the

equations involving wave height only, tidal prism

which had a relatively high R2 = 0.87, but with seven

only, and the product of wave height and tidal prism

may be an outcome of a data set that is predominantly

data points lying outside the 95% confidence limits.

composed of mixed energy inlets. For inlets that are

The exponent value of 0.254 in Eq. (6) indicates that

the intuitively developed parameter (HSP)1/4 having

mainly tide dominated, predictive power of the tidal

prism may be greater than wave height for estimating

units of length appears to possess physical signifi-

depth over the ebb crest. However, it is difficult to

cance that should be explored in future work.

define a unique ebb shoal crest for the complex

shoals, such as channel margin bars, associated with

tidally dominated inlets. For the analyzed data set, the

4. Concluding discussion

limiting depth over an ebb-tidal shoal measured with

Bathymetry data collected by the SHOALS system

respect to MLLW is best described by a quantity

formed of the incident wave height and tidal prism

comprise a highly accurate and valuable source of

as (HSP)1/4.

synoptic information on bottom slopes and geometry

The empirically obtained relationships found here

of inlet morphologic features. At inlet entrances,

describe basic macro-morphological properties of

steepest slopes are located along the shoreline, in

ebb-tidal shoals and entrance channels. In addition

scour holes, around the seaward margin of the ebb

to being of interest for characterizing morphological

shoal, and along the lateral walls of navigation chan-

properties, such relationships are also expected to

nels. Slopes recently dredged entrance channels

ranged from 6j to 8j, with stabilized inlets sustaining

guide simulation of the evolution of inlet morphology

by means of process-based numerical models.

greater slopes than unstabilized inlets. Maximum

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