251 



where U^ = amplitude of tidal velocity. Overbar denotes averaging on the 

 cross-section. 



Residual currents (in a coastal channel) induced by boundary 

 conditions: 



u:: [t)2 (A. 10) 



where a = amplitude of ocean tide. 



The foregoing examples show the strong dependence of residual currents 

 and mixing (dispersion) on the water depth, tidal amplitude, and tidal 

 current. Obviously the effect of sea level rise on transport processes 

 cannot be ignored. 



Research Needs 



I have taken this to imply evaluating the effect of sea level rise on 

 transport processes using the present state of the art of physical 

 processes in estuaries. My suggestion is for a few sea level rise scenarios 

 (i.e., increase in water level and increase/decrease in ocean tidal 

 amplitude) and for estuaries with different dominant transport processes to 

 calculate the change in salt intrusion. Calculations to be carried out for 

 a few schematized estuaries using analytical techniques. This will 

 elucidate the role of changes in depth and ocean tidal amplitude. Using 

 existing calibrated and verified niomerical models, carry out calculations 

 using the actual bathymetry of the estuary. 



REFERENCES 



Abraham, G., de Jong, P., and van Kruiningen, F.E. (1986). "Large scale 

 mining processes in a partly mixed estuary," in J. van de Kreeke , 

 editor. Physics of Shallow Estuaries and Bays, Springer-Verlag, 6-21. 



