Principle Estuaries of Brackishwater

Principle Estuaries of Brackishwater: An estuaries are highly productive ecosystems and support a variety of fish and shellfish species. Brackishwater estuaries are home to a variety of plants and animals, including fish, shellfish, birds, and mammals. Many of these species are found only in estuaries.

Principle Estuaries of Brackishwater

An estuary is the meeting place of river water and seawater they are categories into two types viz, open estuary and the embanked estuary.

1.    Open estuary

An open estuary is created at the bank of river mouth and connected with the sea. Open estuary in the form of a lake containing brackish water. The lake may be perennial because the constantly flow the river water during rainy and winter season all the year round and it may be a seasonal because the flow of river water are very less during the summer. The popular example of open estuary in India is Chilka Lake.

2.     Embanked estuary

It is a made with the earthen soil and occupied limited area of brackish water. It is exposed to sea only at low tides or else it may remain surrounded by continuous chain of barrier islands. The famous examples of embanked estuaries are Cauvery estuary and Adyar estuary in India. 

Principal estuaries

All the estuaries are created along the coastal area of the country close to where the rivers enter the sea. There are two principle estuaries in India viz- Principle estuaries of east coast river system and Principle estuaries of west coast river system The details of some principle estuaries are as follows in table-

1. Principle estuaries of east coast river system

Sr. no.	Estuaries	Location	Source of river water	Source of marine water	Area
1.	Adyar estuary (Embanked)	Tamilnadu, South of Cauvery estuary	River Adyar	Coromandal Coast, Bay of Bengal	6.4 km from mouth of river
2.	Chilka estuary	Puri & Ganjag of Orissa	Branches of Mahanadi	Bay of Bengal	906 sq. km & 1165 sq. km
3.	Cauvery embanked estuary	Near Tiruchirapalli- Tamilnadu	Two branches of Cauvery river	Coromandal Coast, Bay of Bengal	Embanked
4.	Godavari east coast estuary	Andhra Pradesh	Branches of Godavari, Gautami	Kakinada, Bay of Bengal	45 km from the river mouth
5.	Hooghly Matlah estuary of east coast	Sunderban	Branches of Tanga & Hooghly river	Tidy Sea water & Bay of Bengal	2340 sq. km
6.	Krishna estuary  of East coast	Machilipattanm Andhra Pradesh	Krishnas three tributaries	Nizamapatnam, Bay of Bengal	6.28 km from mouth of river
7.	Mahanadi estuary	Cuttack & Puri  district of Orissa	River Mahanadi	Tidal water from Bay of Bengal	42 sq. km From river of mouth
8.	Plicate Lake	A.P. & Tamilnadu	Raayala, Vagu & Kalangi river	Bay of Bengal	44400 sq. km
9.	Vellar estuary	Tamilnadu	Vellar river	Movo port, Bay of Bengal	262 hectare from the river mouth
10.	Vaigai & others (about 7- estuaries)	Ramnad district Tamilnadu	Vellar River	Palk Bay & Gulf of Mannar in Bay of Bengal	93.77 ha by all 7 estuaries.

2. Principle estuaries of west coast river system

Open Estuary