to the shore using the wave model and wave conditions were determined every- 

 where over the study area. The wave-induced current model used the wave in- 

 formation to determine wave-induced currents over the study area. The sedi- 

 ment transport model used the results of the other three models to determine 

 sediment transport. It was verified by comparing its predictions on naviga- 

 tion channel shoaling rates with shoaling rates computed from channel surveys 

 taken during the period November 1980 to December 1981. There was good agree- 

 ment with respect to both trends and magnitudes. 



Model B was next used to determine base conditions corresponding to 

 trapezoidal entrance and offshore channels with a bottom width of 400 ft, a 

 project depth of 40 ft mlw and side slopes of 4H:1V. The sediment transport 

 model results were obtained in terms of channel shoaling rates (ft/year) along 

 the channel. The results were similar to those obtained during verification. 

 In both cases, there was deposition outside the jetty tips. It changed to 

 erosion inside the jetty tips because of circulation due to wave-induced cur- 

 rents. The heaviest deposition rates were predicted near the jetty tips. 

 This is the area where the channel cuts through the offshore bar and where 

 serious shoaling problems were encountered in the field for base conditions. 

 On the basis of the numerical results, the yearly channel shoaling volume 

 between sta -80+00 and sta 325+00 was predicted to be 475,000 cu yd/year. 

 This value was comparable to within ±25 percent of the yearly maintenance 

 dredging volumes recorded by the US Army Engineer District, Jacksonville. 



Model B tested only one plan condition which was called Plan 1 . The 

 plan was to (a) widen the navigation channel to 500 ft, with the widening tak- 

 ing place on the north side of the present entrance and offshore channels; 

 (b) extend the channel on the ocean side, with the extension being at an angle 

 of 20 deg south of the present channel center line at sta -97+76 approxi- 

 mately; and (c) deepen the channel to -49 ft mlw (46-ft project depth plus 

 3-f t advance maintenance) . The channel was to have a trapezoidal cross sec- 

 tion with side slopes of 3H:1V. At the request of OICC, TRIDENT, it was 

 assumed during testing that the landward 1,000 ft of the south jetty would be 

 made sand tight simultaneously. 



In view of the urgent needs expressed by OICC for Plan 1 results from 

 Model B for design of entrance and offshore channels, the wave and wave- 

 induced current models were not rerun for Plan 1 as originally planned. Only 

 the tidal and sediment transport models were rerun. The results of the tide 



