PART IV: PLAN CONDITION TESTS 



Plan 1 



115. Model B tested only one plan condition which will be referred to 

 hereafter as "Plan 1." The plan is to (a) widen the navigation channel to 

 500 ft, with the widening taking 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 20 deg south of the present channel center 

 line at sta -97+76 approximately; and (c) deepen the channel to -49 ft mlw 

 (46-ft project depth plus 3-ft advance maintenance). The channel is to have a 

 trapezoidal cross section with side slopes of 3H:1V. Figure 26 shows details 

 of the planned channel layout and cross section. As requested by the Officer 

 In Charge of Construction (OICC), TRIDENT, the plan tested assumes also that 

 the landward 1,000 ft of the south jetty will be made sand-tight 

 simultaneously. 



116. In view of the urgent need expressed by OICC for Plan 1 results 

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

 wave-induced current models were not rerun for the Plan 1 condition as origi- 

 nally planned. Running the models again would have delayed the results con- 

 siderably. Moreover, since the changes from base to Plan 1 condition of the 

 navigation channel were reflected mainly in the cell size and bathymetry for 

 one row of cells in the computational grid, it was felt the effect of channel 

 modification on waves and wave-induced currents would be minor compared to its 

 effect on tides and sediment transport. 



Computational Grid 



117. As indicated previously in Part II, the computational grid for 

 Plan 1 (Grid 2) retained the major features (overall dimensions, orientation, 

 number of cells, etc.) of the grid for base (Grid 1). The only difference 

 between the two grids lies in the mapping of the row of cells corresponding to 

 the navigation channel. These cells were made 500 ft wide by minor adjust- 

 ments of the cells on either side. In view of the rectilinear nature of the 

 grid, the navigation channel was represented in a stair-step fashion where it 

 turned south. It was assumed that dredging for the navigation channel 



68 



