A littoral is a coastal zone between the low-tide line and the high-tide line. This landscape is constantly changing due to the continuous action of the sea, rivers, and wind, and it may take a variety of forms depending on the geological nature of the coast. also we can say the littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. in relevant to this subject, a coastal state with land territory adjacent to a particular maritime area.
A barrier reef (or barrier island) is a sandbar parallel to the shore at a distance of between a few and several dozen kilometers. A lagoon forms behind the reef.
Deltas form at the mouths of rivers. They result from the accumulation and deposit of sediments carried by watercourses.
Fjords (fjord means “long arm of the sea” in Norwegian) are valleys that were carved out long ago by glaciers, then invaded by water.
A ria is a fluvial valley that is submerged following a rise in sea level or a subsidence of land.