The classical depth-averaged 1-D inlet hydrodynamics equations of Keulegan

(1967) are implemented. These are the momentum equation,

⎛

2*c * f L ⎞ U U

∂*U*

(η

)+⎜K

=0,

- ηO

+

+ *K * ex +

(3)

⎟

⎝

⎠

∂*t*

2*L*

and the continuity equation,

,

(4)

in which *U *= depth-averaged and inlet-length integrated current velocity, *A*C =

breach or inlet channel cross-sectional area below mean sea level (msl), *t *= time,

the bay and in the ocean, respectively, *K*en and *K*ex = entrance and exit losses,

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assumptions of an idealized Keulegan inlet apply, such as vertical walls in the

bay, and sufficiently small bay area to allow the bay surface to move up and

down uniformly in response to tidal flow. In the breach model, the breach

cross-sectional area expressed in Eq. (4) is time dependent. Eqs (3) and (4) are

solved for *U *and η B , respectively.

For the situation of multiple inlets and breaches, if the openings do not

directly interact (with the other Keulegan assumptions still holding), *U *in

Eq. (3) can be replaced by *U*i and *A*C by (*A*C)i for the *i*th opening among *N *total.

Eq. (4) generalizes to:

∑

.

( *A*c )i U i = *A*B

(5)

If waves are present, in addition to increasing the bottom shear stress,

breaking waves produce set up, calculated in the model by standard equations.

The sediment transport rate at the bottom is calculated by total load formula

given by Watanabe et al. (1991),

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