3 Variable Coastal Features 



Coastal features can be examined at a variety of scales. As features are 

 examined in progressively smaller area and greater detail, the morphologic 

 characteristics generally reveal more rapid changes and greater complexity. 

 Some major coastal environments are described herein, with large-scale 

 morphological features being given most attention. These are examined from 

 a variety of perspectives including profile, plan-view, and three-dimensional. 

 Morphological features of smaller scale, such as bedforms, are described in 

 sections where they are often found, including the beach and nearshore zone 

 and tidal inlets. 



Various types of geomorphic changes take place in varying envirormients 

 of the coastal zone, depending upon materials and which processes are locally 

 more important. Large-scale coastal forms generally encompass a wide 

 variety of environments, each exhibiting distinctive processes and responses. 

 For example, the sediments near a barrier island may represent shelf, 

 shoreface, beach/foreshore, dune, back barrier flat, and lagoon environments, 

 each morphologically distinctive (Figure 14). Strandplain coasts and tidal flats 

 contain some, but not all, of the same environments (Figure 14). Coasts 

 strongly influenced by terrestrial fresh water and/or sediment input, e.g., near 

 estuaries and deltas, also have a unique suite of processes, environments, and 

 characteristics. 



Material type also affects coastal form. In locations where unconsol- 

 idated sediments are available, beaches may form if materials are predomi- 

 nantly sand-sized or coarser, although the processes and characteristics of 

 sand-sized beaches and coarse elastics are distinctive. If abundant sand supply 

 is available, coastal dunes may form, If there are significant storms, over- 

 washing, overtopping, and associated features may occur. Mudflats, marshes, 

 and mangrove swamps may form if materials are predominantly fine-grained. 

 Lithified materials coasts also show distinctive processes, with large-scale 

 morphologies typically including cliffs and shore platforms. Locations where 

 organic deposition occurs typically develop hard, shallow reefs, with forms 

 differing from those found in clastic sediment environments. 



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Chapter 3 Variable Coastal Features 



