River-mouth types

The mouth of a river is where it meets the ocean. A river mouth has a coastal part and a river part. between the two there is a mixing zone.

The two basic types of estuaries are without delta or with delta. Under these two main types several subclasses can be differentiated, according to the coastal part, the hydrological regime or the character of mixing. The coasta part of a mouth can be semi-enclosed or open both for with delta and without delta cases.

The hydrological regime may be tidal or not tidal.

Vertical mixing of river water and sea water may be: well mixed, partially mixed or not mixed, but having a sharp interface.