Structure

== Introduction ==

Rubble mound coastal structures, such as breakwaters and jetties, and groins, are built to protect coastal development from waves and tidal action. Because typically comprising of irregular, rough stones or concrete armor units, rubble mound structures usually contain voids among individual stone or armor units.  As a result, the voids allow absorption and dissipation of wave and tidal current energy but also provide pathways for flow and sediment moving through structures. In numerical modeling, rubble mound structures are often treated as solid and impermeable walls. However, depending on the design of and the armor units used for rubble mound structures, the volume of water and quantity of sediment transport through breakwaters, jetties, and groins can be substantial to alter flow pattern, increase sediment deposition, and induce significant beach erosion and shoreline change in protected areas (TM 5-622/MO-104/AFM 91-34 1978). 

In coastal applications, it is important for hydrodynamic and sediment transport models to simulate wave transmission and flow penetration through rubble mound structures (d’Angremond et al. 1996; Garcia et al. 2004; Tsai et al. 2006). The present study applies the methodology simulating the permeability of rubble mound structures (Reed 2010) in the CMS to Dana Point Harbor on the southern California coast. The hydrodynamic calibration and sediment transport validation are conducted against the field measurements.