• Prawns are farmed in brackish waterPrawns image by Thomas Leonhardy from Fotolia.com
  
  Water contains a varying amount of total dissolved salt (TDS). Freshwater has a TDS content of less than 1,000 parts per million (ppm), and seawater has a TDS of 30,000 to 40,000 ppm. Brackish water falls in between the two, with a TDS within 1,000 to 5,000 ppm. Brackish water occurs along coastal areas where seawater meets freshwater discharges and in areas of high salt occurrence in rocks and soils, where brackish groundwater results, especially if rainfall is low and evaporation rates are high.
  
  

Culture of Fish and Shrimp

• Brackish water fish farming is practiced in many countries. Fish, shrimp and prawns are farmed in the United States, Israel , Australia, Pacific Rim and Indomalaysian countries. Aquaculture is a means of ensuring quality in terms of exposure to diseases, heavy metals and other pollutants and preserving wild populations of fish and seafood.
  
  

Hydroponics

• In Israel's Arava Valley, agriculture is limited due to scarce rainfall and the quality of available groundwater for irrigation. Underground water sources are brackish, as are springs. A method of using brackish water as a base for hydroponic plant culture was devised by M. Schwarz of the Negev Institute for Arid Zone Research.
  
  

Desalination

• In countries with low rainfall and consistent droughts, brackish water along coasts is desalinated by reverse osmosis for drinking and agricultural use. Spain has developed brackish water desalination plants to treat well water, waste water and superficial water. The costs of producing desalinated water is affordable and in some areas the only solution to having sufficient supplies of potable water. Disposal of the resultant brine can be a problem, and research is ongoing for safe inland discharges of brine. As of 2002, Port Hueneme, Calif., had three brackish water desalination plants in operation producing over three million gallons of drinking water daily.
  
  

Wildlife

• Fish and animals the world over use the coastal areas where freshwater meets seawater as spawning, breeding and nesting grounds. Salmon and eels are examples of important commercial fish that spend part of their lives in both marine and fresh water environments. Brackish water estuaries provide essential staging areas for such fish during different parts of their life cycle. Other important fish in estuaries include flounder, sole, mullet and smelt.
  
  

Brackish Water Supports Useful Natural Vegetation

• Mangrove swamps form in brackish water areas of subtropical and tropical lands. Mangrove forests form important buffering areas to protect land against the onslaught of cyclones and tsunamis, greatly lessening damage and loss of human life. Mangrove swamps also protect the coast from erosion.