Equations 76 and 77 are used for calculating sediment transport beyond the 



surf zone. In thes e equatio ns, v is interpreted as the total velocity Vj, 



V"~2 2~ 

 u„ + V and v^ is obtained from the relation 



(78) 



where t is the bed shear stress and C is the Chezy coefficient. From 

 q , the local transport rates q and q are obtained as before. 

 Transport in the vicinity of inlets 



70. The flow and sediment transport in the vicinity of tidal inlets 

 differ markedly from the flow and sediment transport in the surf zone for a 

 straight open coast. The bathymetry in the inlet area is highly irregular 

 with the presence of channels, bars, and shoals. The breaker line is gener- 

 ally shifted farther offshore and is irregular. Breaking and decay of waves 

 and wave-induced currents are the major mechanisms for transport of sediment 

 in the surf zone near straight coasts, with tidal currents being of secondary 

 importance. Generally u is much less than v . In the vicinity of 

 inlets, tidal currents are a major mechanism comparable to wave-induced cur- 

 rents. Moreover, u and v may be comparable. We are primarily inter- 

 ested in the transport and deposition of sediment in the navigation channel. 

 There is no guidance in the open literature as to how sediment transport in 

 this area should be handled. In view of the factors mentioned previously, the 

 model uses the Ackers and White formulation modified for the presence of waves 

 (Equations 76 and 77) in this area. From previous experience (Vemulakonda 



et al. 1985), this approach was found to yield satisfactory results. 

 Erosion and deposition 



71. In the case of noncohesive sediments, once the transport rates of 



sediment q and q are known, changes in bed elevation can be determined 

 X y 



from the continuity equation 



3r ^^ ^*1 



42 



