1 Introduction 



This literature review addresses sediment transport across the inner por- 

 tion of the continental shelf, also referred to as the shoreface, or, as in this 

 report, the inner shelf (Figure 1). The inner shelf extends from the sea- 

 ward edge of the surf zone to the landward edge of the continental shelf. 

 It is affected by the strong agitation that results from sediment resuspen- 

 sion caused by shoaling of nonbreaking waves. The inner shelf is friction- 

 dominated by both bottom and sea-surface boundary layers which overlap 

 and frequently occupy the entire water column (Wright, in press). The 

 inner shelf differs from the surf zone, which is also characterized by 

 strong agitation of the bed by waves. The bed of the surf zone, however, 

 is affected by the bore-like translation of waves following wave breaking 

 (Komar 1976), and by wave-induced longshore currents and rip currents. 



Cross-shore transport of sediment across the inner shelf has a great 

 effect upon short- and long-term fluctuations of beach and surf zone sand 

 storage as well as the morphology and stratigraphy of the inner shelf. 

 Although surf zone and nearshore processes and sediment transport have 

 been extensively addressed in the literature, inner shelf processes and sedi- 

 ment transport, particularly in the cross-shore direction, are not well 

 understood. The complexity and interdependence of the mechanisms con- 

 trolling transport on the inner shelf make it very difficult to comprehen- 

 sively understand and describe the processes affecting sediment on the 

 inner shelf. In response to this, Wright (1987) stated that a goal of the 

 scientific community should be "to devise a more universal conceptual 

 framework capable of better accounting for shoreface transport, erosion, 

 and deposition in time and space." 



Knowledge of sediment transport to and from the inner shelf region has 

 important implications to engineering works such as beachfill design and 

 dredged material placement. In computing a sediment budget for a beach- 

 fill project, offshore gains and losses are usually assumed to be negligible 

 in the sediment budget calculations. While this assumption recognizes the 

 difficulty in quantifying inner shelf exchanges, it is probably incorrect dur- 

 ing significant events. Defining limits for the active nearshore profile 

 under varying conditions can aid in placing dredged material so that it 

 will likely move onshore, offshore, or remain stable. 



Chapter 1 Introduction 



