What is a river mouth?
Coastal lowlands contain a huge diversity of landforms.
Marine and fluvial processes determine four types of river mouths:
- Mouth forming a delta: they are formed in coastal areas with micro tides and a certain slope gradient, where coarse sediments are the first to be deposited, while finer sediments travel further.
- Simple river mouth: these are common in the case of shorter water courses, which do not form deposits on the coastal area and do not branch out.
- Mouth forming an estuary: the water course widens as it reaches the coast. It happens when tidal influence is stronger than the influence of the river flow.
- Mouth forming a lagoon: they occur when the river reaches a coastal lowland and the river is drowned by a shallow sea, forming a lagoon. Sediments from the river deposit and rise to the water surface forming a shoal or sandbar. A shoal or sandbar is a ridge that surrounds the lagoon and separate it from the sea. The lagoon can be connected to the sea, and tidal action be felt, or not.