113. At the time Model B computations were made, up-to-date field sur- 

 vey information was not available on channel bathymetry between sta 325+00 and 

 sta 399+74, nor was up-to-date bathymetric information available for areas on 

 either side of the channel. Model B used the best available information, 

 which usually was CESAJ construction dredging survey information and the 

 bathymetric information from NOS charts. Unfortunately, this information does 

 not seem to represent the current bathymetry for the reach of the channel be- 

 tween sta 325+00 and sta 399+74 and the areas of either side of the channel in 

 this reach, according to the latest CESAJ surveys. These surveys seem to 

 indicate that the depths may be greater (by 5 ft or more) in this reach. For 

 this reach of the channel, the information available to us at the time of com- 

 putations indicated the depths were greater than the existing project depth of 

 40 ft and that the channel seemed to be in a state of erosion; therefore it 

 did not require maintenance dredging. There was no quantitative information 

 available on erosion/deposition rates for this reach. 



114. The sediment transport model followed the same testing procedure 

 as it did for verification. The model was run for 200 prototype days, and its 

 results were converted to channel erosion/deposition rates (ft/year) . For 

 base tests, the entire length of channel offshore of sta 399+74 was consid- 

 ered. The channel was divided into ten zones (zones 1 to 10 in Figure 23). 

 Figure 24 shows the erosion/deposition rates by zone for base. When the 

 results for verification and base are compared (Figures 22 and 25) , it is 

 observed that there is similarity in the trends and magnitudes. This is not 

 surprising since the channel bathymetry in the two cases is not that much 



500 ft 



JA^ 



1 I 2____1__3_ |__4__L_5_J 6|7| 8| 9\M 



1 



T 



-100 -50 



50 100 150 200 

 DISTANCE, 100 ft 



250 300 350 400 



Figure 23. Zone numbers assigned to channel reaches for 

 base and Plan 1 results 



65 



