Coastal zone: The terms 'coastal zone' means the land‐sea interface, however a generally accepted definition does not exist. Commonly used is “the interface between land and sea, defined as the part of the land affected by its proximity to the sea (influence of marine processes), and the part of the sea affected by its proximity to the land (influence of terrestrial processes) (1).“
However, for planning purposes sometimes fixed boundaries are defined e.g. zone between shoreline and 3 km inland from the coast (Danish Planning Act, 1991) or a strip between shoreline and 200 m landwards (Spanish Shores Act, 1988).
Other definitions are based on physical processes, for example: „a region a few kilometres wide on either side of the shoreline where local thermal circulations such as the sea breeze and land breeze occur“ (2) or ”…coastal zones include the splash zone, the high intertidal zone, the low intertidal zone, and the low tide zone“ (3). In some cases the coastal zone is defined seawards up to the continental shelf edge.
Littoral zone (shoreface): “is part of the active coastal zone, situated seaward of the low water line. This zone extends seaward from the foreshore to some distance beyond the breaker zone. The littoral zone is the zone in which littoral morphodynamic processes take place, related mainly to longshore sediment transport and cross-shore sediment transport…” The width of the instantaneous littoral zone varies dependent of the wave conditions.” (4)
Coastline: “Technically the line that forms the boundary between the coast and the shore, i.e. the foot of the cliff or the foot of the dunes. Commonly, the line that forms the boundary between the land and the water. See also: Classification of coastlines.” (4)
Shoreline: “The intersection between the mean high water line and the shore. The line delineating the shoreline on Nautical Charts (Sea Maps) approximates this Mean High Water Line. The shoreline is not easy to identify in the nature in contrast to the coastline, which is based on a clear morphological shift between the shore and the coast.” (4)
Transitional waters: in the European Union, the definition is “bodies of surface water in the vicinity of river mouths which are partly saline in character as a result of their proximity to coastal waters but which are substantially influenced by freshwater flows.” (European Water Framework Directive, 2000/60/EC). Estuaries, lagoons and several semi-enclosed bays are addressed as transitional waters.
Coastal waters: represent the interface between land and ocean. In the European Union, coastal waters form a belt between the baseline (transitional waters) as landward boundary and one nautical mile (1.8 km) offshore of the baseline (European Water Framework Directive, 2000/60/EC). The baseline represents an official simplified coastline. Usually the outline of islands, mouths of rivers or bays are connected by straight baselines.
Territorial waters: is a belt of coastal waters extending at most 12 nautical miles from the baseline of a coastal state (United Nations Convention on the Law of the Sea, 1982)
Coastal seas: usually means the sea between coastline and continental shelf edge. It includes the enclosed and semi-enclosed European seas, the regional seas, such as the Mediterranean Sea (2,500,000 km2 surface area, 1,500 m average depth), the Black Sea (508,000 km2 1,240 m), the North Sea (575,000 km2, 94 m) and the Baltic Sea (422,000 km2, 55 m).