at x=xg, the ratio p of the total sediment transport that bypasses the groin is,
∞ 1 d ξ 2
where ξ = ratio of breaking waves given by ξ = exp ( -(γ b h / H x )2 ) , in which Hx = local
root-mean-square (rms) wave height neglecting wave breaking.
Assuming an equilibrium profile (h=Ax2/3), the bypass ratio p is a function of three non-
dimensional parameters and the incident wave angle, namely: xg/Hrms,o, Hrms,o/Lo, A/Hrms,o1/3
and θo. However, the dependence on refraction is weak for small wave angles at breaking.
Fig. 3 illustrates how the bypass ratio depends on normalized groin length and deepwater
wave steepness for a fixed value on A/Hrms,o1/3.
Normalized Groin Length (xg/Hrms,o)
Fig.3. Bypass ratio as a function of normalized groin length and deepwater wave steepness for
Inlet Sediment Storage and Transfer
Cascade includes the Reservoir Model (Kraus 2000) to describe inlet sediment storage
and transfer. The inlet is schematized into distinct morphological units (ebb shoal proper,
bypassing bars, and attachment bars) and formulated relationships for how the sediment
moves between them. Sediment that approaches the inlet and bypasses the jetty is
transported to the ebb shoal. From the ebb shoal, the material is transferred to the
bypassing bar and then further downdrift to the attachment bar. From the attachment bar
the sediment is transported along the shore. Each morphological unit is assumed to have a
certain equilibrium volume for fixed hydrodynamic and sediment conditions. As the
volumes approach equilibrium values, more sediment is transferred downdrift. Kraus
(2000) assumed that the sediment passing through each unit is proportional to the ratio
between the actual volume and the equilibrium volume for the unit. If equilibrium is
Larson, Kraus, and Hanson