Lagoon is a stretch of brackish or salt water separated from the sea by a sandbank, bars, reefs, etc. The action of wind and waves along coasts builds spits and bars in the inlets of seas isolating lagoons from the sea. They are commonly found off the deltas of large rivers like the Ganges, the Mahanadi, etc.
The Chilika lake of Orissa, the Pulicat lake of Tamil Nadu and the Kolleru lake of Andhra Pradesh are lagoons. Strong on shore winds are also capable of pushing the coastal sand dunes along beaches landwards. They may enclose marshy lagoons.
(i) Lagoons are found only in coastal areas, usually near the mouths of rivers, while lakes may be formed in any geographical location, in highlands or in inland basis.
(ii) Lagoons have brackish water while a lake may have fresh water or salty water.
(iii) Lagoons are formed due to wind and wave action in the coasts. Lakes may be of tectonic origin or may be formed due to river action, glacial action, and wind. They may also be human-made artificial lakes.
