Coastal Area Definition

“Coastal Zone” or “Coastal Area” is the name given to the boundary between the land and the ocean which is not clearly define line on a map, but occurs through gradual transition region. Defining this boundary is of more than academic interest to coastal planners and managers. This definition is essential for government to create administrative systems, or set out policies to guide decision making within this fragile area. Generally, Coastal planners and managers define this area by two ways;

a) Definitions by Biophysical ;

The line that joins land and ocean is constantly moving, with the rise and fall of tides and the passing storms, creating a region of interaction between land and sea. Parts like beaches, coastal marshes, mangroves and fringing coral reefs are part that clearly has strong interactions between land and ocean. Whereas, there is part that may be more distant from immediate coast but still play an important role in shaping coastal environment, one of the most important is the river, which act as freshwater and sediment storage and deliver for coastal environment. Therefore a coastal area can be defined as “the band of dry land and adjacent ocean space including water and submerged land in which terrestrial processes and land uses directly affect oceanic processes and uses.”(Ketchum 1972) This definition based on the interaction between oceanic and terrestrial processes and uses: coastal areas contain land, which interact with the ocean in some way; also ocean space which interacts with the land. To summarize, Coastal area:
a) Contain both land and ocean components.
b) Have land and ocean boundaries that are determined by the degree of influence of the land on the ocean and the ocean on the land;
c) Constantly changing in width, depth or height.


b) Definition through Policy-oriented

Policy-oriented limits the coastal definition in four possible ways;

a) Fixed distance definitions
Specify a fixed distance away from the coast, which is considered ‘coastal’, usually apply to the limit of governmental jurisdiction.

b) Variable distance definitions
Definitions are set from some measure of the coast, usually high water mark, boundaries are not fixed, but vary along the coast according to;
• physical features
• biological features
• constructed landmarks
• administrative boundaries

c) Definition according to use
Definition depends upon the purpose for which the definition is intended. From both management and scientific points of view, the extent of coastal area will vary according to the nature of management issue, by using 4 concepts;
• an administratively designated area
• an ecosystem area
• a resource base area
• a demand area

d) Hybrid definitions
Definitions mix one type of definition for the landward limit of the coastal area and another for the seaward limit. Commonly practiced by governments that have a fixed limit of jurisdiction over near shore waters.