c. The inner shelf is often not sand rich and in some areas is strongly 

 influenced by the geological framework. 



d. The profile of equilibrium equation provides an average inner shelf 

 profile cross section, but does not accurately predict equilibrium 

 profiles at specific inner shelves. 



Present-day models concerning inner shelf cross-shore sediment trans- 

 port and based on the profile of equilibrium equation (Pilkey et al. 1993) 

 do not adequately describe nearshore sediment transport as they say inner 

 shelves can be described and differentiated solely on the basis of sediment 

 grain size and a broadly defined wave climate. However, these models do 

 represent the most up-to-date estimation of inner shelf cross-shore sedi- 

 ment transport and are particularly useful in that they allow an engineer or 

 scientist to explore storm impact on a location using a general approxima- 

 tion of the profile. 



Many problems must be understood before we can gain a reasonable 

 understanding of inner shelf and nearshore equilibria/disequilibria and the 

 associated rates of and directions of cross-shore sediment transport 

 (Wright et al. 1991). A goal for the coastal engineering community should 

 be "to devise a more universal conceptual framework capable of better 

 accounting for inner shelf transport, erosion, and deposition in time and 

 space" (Wright 1987). Accomplishing this goal would help to do the 

 following: 



a. Garner a better understanding of the physical oceanography of the 

 inner shelf, including the vertical segregation of flows and 

 cross-shelf variations of these flows. 



b. On a morphodynamic perspective, study the bottom boundary layer 

 processes that provide the connecting link between hydrodynamics 

 and resulting morphologic change via sediment transport. 



c. Study the environmental end members (i.e. other sites) in order to 

 create a comprehensive inner shelf morphodynamic model. 



d. Acquire more detailed time series data on near-bottom flow structure, 

 sediment fluxes, bedform behavior, and substrate microstratigraphy. 

 As their empirical base is expanded, so, too, theory and models 

 should be expanded. 



e. More accurately predict ripple geometries and their applicability to 

 mixed sediment size distributions and combined waves and currents. 



/. Create more realistic paradigms for shelf-nearshore equilibrium that 

 take explicit account of the natural suite of near-bottom flows and 

 of the fundamental roles played by time-varying bed 

 micromorphology. 



66 



Chapter 5 Summary 



