grain sizes, 0.25 nun and 0.40 mm. For these simulations, the model grid 

 spacing was set at 5 m and the time step at 20 min. 

 Existing condition 



The existing condition, representing the original beach prior to nourish- 

 ment activity, is shown by the dashed line in Figs. 5a and 5b. A 2-m berm is 

 backed by an infinitely high seawall, although its crown is depicted at a 2-m 

 elevation in this and subsequent figures. The original profile decreases 

 linearly to the elevation of 1 m, at which point an equilibrium shape given by 

 Equation 1 is used to extend the profile into deeper water. 



Simulations showed that the 0.25-mm sand beach eroded on the foreshore, 

 and a small bar formed with the crest located about 120 m from the base line. 

 In contrast, the 0.40-mm sand beach accreted slightly on the foreshore, 

 indicating that the transport was directed onshore by Equation 3. At mid- 

 storm the berm was completely submerged and the beach eroded considerably at 

 the seawall for both sand sizes. Offshore, a double bar developed; the inner 

 bar was created at the beginning of the surge , whereas formation of the outer 

 bar corresponded to the peak surge and maximum wave height. By post-storm, 

 the berm had eroded further at the wall, slightly more so for the 0.25-mm sand 

 beach than for the 0.40-mm sand beach, and a single large bar appeared on both 

 profiles. The bar on the finer sand beach is broader and of lower elevation 

 with respect to the initial profile than the coarser sand bar. It is inter- 

 esting to note that the position of the shoreline at post-storm is at about 

 the same location (approx. 75 m) for both beaches; however, sand moved further 

 offshore on the finer sand beach, and its subaerial section is more deflated. 



The lower-steepness waves arriving during the 7-day recovery period passed 

 over the storm bars on both beaches, causing little change to the storm bar 

 shape. The storm bars thus became relict bars as observed to persist in 

 deeper water on real beaches. The recovery swell broke in shallower water, 

 creating a small secondary bar inshore on both beaches. The inner bar was 

 formed by onshore transport, producing a deep trough between the storm bar and 

 inshore bar. Both beaches accreted to the limit of runup for the swell waves. 

 Artificial berm fill 



Simulation results for an artificial 3-m high berm are illustrated in 

 Figs. 6a and 6b. A beach fill of volume 85 m 3 /m with the same grain size as 

 the existing beach was placed mainly on the subaerial portion of the profile. 



101 



