and in the southerly direction, as one would expect. The currents are strong 

 over the north and south shoals because of wave breaking and decay. The pat- 

 tern of the currents is complicated. Currents move in an easterly direction 

 along the interior of the north jetty and westerly direction along the 

 Interior of the south jetty. 



104. In summary, the overall results of the wave and wave-induced cur- 

 rent models used for verification and base conditions are reasonable and 

 behave in a manner one would expect, given the complicated bathymetry of 



St. Marys Inlet region and the two jetties on the inlet. The incident waves 

 respond differently to the bathjonetry, the shoals and the jetties, depending 

 on their direction of incidence. The wave-induced currents depend on the 

 bathymetry, the waves everywhere in the grid, and whether or not the waves 

 break and decay in a given region of the grid. 



Sediment Transport 



Verification tests 



105. In order to make a strict verification of the sediment transport 

 model, it is necessary to have either long-term (several years long) informa- 

 tion on shoaling rates in the navigation channel and bathymetric changes in 

 the general area or actual wave measurements made simultaneously with measure- 

 ments on shoaling rates and bathymetric changes over a shorter time period (a 

 few months). The latter type of data are not available for the project area. 

 As for the former, examination surveys are available for the channel. As men- 

 tioned previously, the approach used by the sediment transport model does not 

 account for extreme storms. So the prototype data selected should not include 

 periods of such storms. As for dredging, it is possible to simulate dredging 

 in the numerical model provided detailed information is available on the loca- 

 tions and durations of dredging and the amounts of material dredged at each 

 location. Usually, such detailed information in terms of computational grid 

 cells is not available from dredging records. Therefore the prototype data 

 should not include periods of dredging. In the case of St. Marys Inlet, the 

 navigation channel was deepened to the existing condition (40-ft project 

 depth) in 1978 and 1979 so only 5 to 6 years of prototype data are available. 

 The channel still has not stabilized after the deepening. Sediment transport 

 and other processes continue to be in a state of transition. Out of the 



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