Since Florida is a peninsula between a gulf and an ocean, the state has three major types of water at its disposal.  The three types of water are saltwater, freshwater, and brackish.  Most people know what saltwater and freshwater are.  In this article, we will discuss what brackish water is.

What is Brackish Water?

Brackish water is water that is between freshwater and saltwater with regard to the level of salinity.  Freshwater contains fewer than .5 grams  per liter. Saltwater has a salinity level of more than 30 grams per liter. If water has a salinity level between .5 grams and 30 grams per liter, that is brackish water.

Where Do You Find Brackish Water?

Brackish water is anywhere where saltwater and freshwater meet naturally.  The most common areas to find this type of water are estuaries, mangrove swamps, seas or lakes, and marshes.


Estuaries are the area where a freshwater river meets the saltwater ocean.  The biggest estuary in the United States is the Mississippi River Estuary where the freshwater from the might Mississippi River dumps into saltwater of the Gulf of Mexico.  Estuaries play an important role in the environment as they create a rich habitat of vegetation and wildlife.  The vegetation acts as a natural barrier to storm surges caused by inclement weather.  Due to the vegetation and natural protection estuaries provide for wildlife, estuaries are fertile grounds for fishing.


Another common area of brackish water is in mangrove swamps.  Mangroves are vegetation that thrives in brackish water.  Although mangrove swamps can be found in estuaries, they differ in the fact that the salinity in mangrove swamp changes with the tide.  Unlike estuaries, where freshwater dumps into saltwater, mangrove swamps are where saltwater rises with the tides into freshwater areas.  The mangrove swamp root system is highly complex and is one of the best natural barriers to storm surges and tidal waves.  Florida has some of the largest mangrove swamps in the United States.  An interesting bit of trivia, the mangrove swamps of South Florida are the only place where the American Alligator and American Crocodile coexist with each other.

Seas or Lakes

Brackish seas or lakes occur when freshwater from a river or stream flows into a saltwater lake or sea.  It is very similar to an estuary, with the exception that estuaries happen when the freshwater goes into the ocean.


A brackish marsh is formed when a saltwater marsh is significantly diluted by an influx of freshwater.  Brackish marshes are commonly found upstream of estuaries where due to tides and storm surges, saltwater collects inland.  When the water evaporates, the salt minerals are left behind.  When freshwater mixes with the salt in the marsh, it creates a brackish marsh.