248 



Research Needs 



To evaluate the effect of sea level rise on tides and tide -induced 

 circulation, I suggest that, for a number of sea level rise scenarios, 

 including changes in the offshore tide, 



o calculations be carried out for a few schematized estuaries, using 

 analytical techniques and field equations that include friction; 



o calculations be carried out for a number of real estuaries using 



calibrated and verified hydrodynamic models (San Francisco Bay, Tampa 

 Bay, Biscayne Bay, etc.)- 



SECT. 6. INTERACTION WITH NATURAL FEATURES AND CONSTRUCTED WORKS 

 Natural Features 



Natural Inlets: An increase in sea level increases the cross - 

 sectional area and the bay tidal amplitude. Assuming a uniformly 

 fluctuating bay level the effect of these changes on the inlet velocity 

 follows from 



27r Afeabd + ^) 



U= ^— (A. 5) 



e 



T Ac (1 + f-) 



where u is the amplitude of inlet current velocity, A^ is the surface area, 

 T is tidal period, A^, is inlet cross-sectional area, a]-, is bay tidal 

 amplitude, and a and e are the increase in respectively the bay tidal 

 amplitude and the cross -sectional area. If a/a]-, < e/A^ the inlet velocity 

 decreases, if a/a^ > e/A^, the inlet velocity increases. 

 Stability of inlets can be based on 



Ac = aP"! (A. 6) 



In evaluating the effect of sea level rise on inlet stability it should be 

 realized that not only P but also a and m are affected by sea level. 



