Fresh, Salt and Brackish Water
By: Amber Dixon
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, icebergs, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams.
The definition of freshwater is water containing less than 1000 milligrams per liter of dissolved solids, most often salt. The global distribution of freshwater resources varies greatly from region to region. An 'inventory' of Earth's waters shows that approximately 97% of the global water supply is found in the oceans, which are saline. A very small amount of salty water is also located in saline lakes. The remaining water inventory (3%) is 'freshwater'. Permanent ice is the largest freshwater storage on Earth, accounting for about 2% of the total global supply - or nearly 69% of the total freshwater supply. Freshwater is also found beneath the Earth's surface as groundwater (approximately 30% of the total freshwater supply) and in surface water storages such as lakes, streams, swamps and marshes. Minute amounts of freshwater are also stored in the soil, the atmosphere and in biological organisms.
Saltwater, or salt water , is a geological term that refers to naturally occurring solutions containing large concentrations of dissolved, inorganic ions. In addition, this term is often used as an adjective in biology, usually to refer to marine organisms, as in saltwater fish.
Saltwater most commonly refers to oceanic waters, in which the total concentration of ionic solutes is typically about 35 grams per liter (also expressed as 3.5%, or 35 parts per thousand). As a result of these large concentrations of dissolved ions, the density of saltwater (1.028 g/L at 4° C) is slightly greater than that of freshwater (1.00 g/L). Therefore, freshwater floats above saltwater in poorly mixed situations where the two types meet, as in estuaries and some underground reservoirs.
Brackish water or briny 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.
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 .