comparative analysis of historical maps, charts, and aerial photographs that 

 show changes over decades or centuries. 



Scope 



This report identifies and briefly discusses variable coastal features, the 

 processes and factors that affect them, and the available technology and 

 techniques for their study. The features discussed here are, for the most part, 

 associated with the direct effects of marine and lacustrine processes. 

 Terrestrial features and processes that occur inland of the coastline are 

 discussed briefly in the following section. They are described in greater detail 

 in many standard texts dealing with geomorphology, physical geography and 

 physical geology (Chorley, Schumm, and Sugden 1984; Strahler and Strahler 

 1987; Bloom 1991). 



Coastal Classification 



Shorelines are influenced by a combination of nonmarine and marine 

 processes. Shepard's (1963) genetic classification of coasts reflects the 

 dichotomy of nonmarine and marine influences. Primary coasts, according to 

 his classification, are essentially nonmarine in origin and are shaped mainly by 

 land erosion, subaerial deposition, volcanism, and diastrophism. Secondary 

 coasts are shaped by marine processes, including wave erosion, marine 

 deposition, and organicA)iologic modification. 



Primary shorelines have yet to be appreciably modified by marine pro- 

 cesses. Land erosion coasts include: (a) drowned river valleys; (b) drowned 

 glacially eroded coasts, including fjords; and (c) drowned karst topography. 

 Coasts of subaerial deposition include: (a) those principally reflecting river 

 deposition with either deltas of various forms or alluvial plains; (b) those 

 reflecting glacial deposition, with partially submerged moraines, drumlins, or 

 drift features; (c) wind deposition with active or fossil dunes, or sand flats; 

 and (d) those reflecting landslide deposition and perhaps other forms of mass 

 wasting. Volcanic coasts include those influenced by lava flows, tephra or 

 volcanic ash, and volcanic collapse or explosion. Coasts may also be shaped 

 by diastrophic movements, which produce faulted and folded coasts of various 

 types, and coasts with sedimentary extrusions such as salt domes and diapirs. 



Information Sources 



The most direct and accurate means of obtaining information on the vari- 

 ability of coastal features in an area is by conducting repetitive surveys over a 



Chapter 1 Introduction 



