:shrug:
Brackish water is water that has more
salinity than
fresh water, but not as much as
seawater. It may result from mixing of seawater with fresh water, as in
estuaries, or it may occur in brackish fossil
aquifers. The word comes from the
Middle Dutch root
"brak," meaning "salten" or "salty". Certain human activities can produce brackish water, in particular certain
civil engineering projects such as
dikes and the flooding of coastal marshland to produce brackish water pools for
freshwater prawn farming. Brackish water is also the primary waste product of the
salinity gradient power process. Because brackish water is hostile to the growth of most terrestrial plant species, without appropriate management it is damaging to the environment (see article on
shrimp farms).
Technically, brackish water contains between 0.5 and 30 grams of
salt per
litre—more often expressed as 0.5 to 30 parts per thousand (ppt or ‰). Thus,
brackish covers a range of
salinity regimes and is not considered a precisely defined condition. It is characteristic of many brackish surface waters that their salinity can vary considerably over space and/or time.