Fig. 6. Computed Rossby number (defined as R0 jUs=fRsj) shaded contours for the four idealized inlets at maximum flood.

Hench_et_al_CSR_02
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Rattray, 1966; Jay and Smith, 1988) as well as for

ilar, they may have very different tidal circulation

buoyant coastal discharges (Garvine, 1995; Kour-

and dynamics. Thus the lack of any inlet geometry

afalou et al., 1996). Thoughtful reviews of

or velocity characteristics appears to be a sig-

classification schemes are given by Dyer (1997)

nificant weakness in extending the Hayes (1979)

and by Jay et al. (2000). Much less work has been

scheme to tidal inlets.

done for inlet classification, although inlets have

Here we develop a new inlet classification

been classified following the Hayes (1979) barrier

scheme based on two dimensionless parameters

island scheme. The Hayes classification uses mean

derived from the lateral tidal momentum balances

wave height and mean tidal range to assess the

and intrinsic inlet geometry. Following the results

relative role these two processes play in shaping

from Section 4, we first find the length scale at

barrier island morphology. The scheme has sub-

which the centrifugal and Coriolis accelerations

sequently been used for inlet classification, but the

are comparable. Setting R0 1 and solving for

physical justification for this seems limited. One

Rs1; the radius of curvature for which the Rossby

can imagine two inlets in close proximity along a

coast with similar mean tidal ranges and mean

number is one

wave heights. These two inlets would be classified

Rs1 Us=f :

the same using Hayes (1979). However, if the