The Blue Zone of the Planet Earth - Blue Carbon Reservoir of the Blue Planet - page 4

Fig. 1.3 Types of
estuaries. a Coastal plain,
b tectonic, c fjord, d bar-
built

1. On the basis of salinity, estuaries can be
grouped into the following types
(a) Oligohaline: In this type of estuary, the
freshwater mixes with the saline water in
such proportion that the water ultimately
becomes uniformly saline. Such estuaries
are common where small rivers meet the
seas, e.g., Haldi River of West Bengal
(India).
(b) Mesohaline: It is that type of estuary
where the estuarine water has medium

salinity due to proportional mixing of the
freshwater and saline water, e.g., Maha-
nadi River of Odisha.
(c) Polyhaline: In this type of estuary, there
are areas, where there is distinct variation
of salinity owing to the tidal water intrusion
into the river mouth, e.g., estuaries adjacent
to Bay of Bengal and the Indian Sundar-
bans. The estuarine complex of this man-
grove-dominated deltaic is broadly divided
into three salinity regimes (Table 1.1 ).