Crack the H2O code with our water science glossary

14 August 2023

This Science Week, quench your thirst for water science knowledge with our handy glossary! You can use this glossary to familiarise yourself with some of the more common terms that can be found in research reports and factsheets from our National Water Grid Science Program. 




Aquifers are bodies of rock or unconsolidated material. They hold enough accessible water to be usable as a water resource. 
Brackish water This is water that generally contains between 1,000 – 10,000 Mg/L (milligrams per litre) TDS (total dissolved solids), putting it between freshwater (0 – 1,000 Mg/L TDS) and saline water (10,000 – 100,000 TDS, in this instance the solid is salt). Seawater is generally around 35,000 Mg/L TDS.
Desalination  This is the process of removing dissolved mineral salts from water. There are different methods of desalination, such as reverse osmosis.
Gaining waterways  Waterways (e.g. sections of rivers) that gain water from incoming flows of groundwater. 
Groundwater Groundwater is water that has accumulated beneath the water table underground, such as in the cracks or spaces of aquifers.
Groundwater discharge Groundwater discharge happens when groundwater flows onto the surface of the land. It discharges as a spring, into surface water such as rivers and lakes, or through uptake by vegetation and plants.
Groundwater recharge Recharge or ‘refilling’ of groundwater occurs when surface water from rain, rivers or lakes drains downwards into an aquifer.
Groundwater system A saturated sequence of rocks or sediment where groundwater can flow. The water travels underground through spaces between grains of sand and gravel, gravels and other alluvium or through cracks in rocks.
Hydrogeology The study of the occurrence, distribution and movement of groundwater in soil and rocks. This includes the study of groundwater recharge and flow through the subsurface (underground). It also includes the study of interactions with surrounding soil and rocks.
Irrigation This is the supply of water to land areas. Supply is usually to farms to help grow crops but can also be used to water landscaped plants and lawns. It may also be used to help refill natural waterways.
Reverse osmosis The process of removing contaminants from a water resource by using a semipermeable membrane.
Saturated zone This is the area beneath the water table where water fills all the spaces between the sediments.
Salinity This is the concentration of salts in water or soil.
Sediments Anything that settles at the bottom of water, such as soil, sand and fine rock.
Semipermeable membrane A barrier that only certain molecules can pass through.
Spring  A point where groundwater flows from an aquifer to the land surface.
Spring, artesian A spring where the groundwater pressure is higher than the atmospheric pressure. The water is pushed up through the ground through a rock fracture or porous layer.
Spring, mound Springs that have developed mounds, sometimes over thousands of years. Mounds are made up of salts and minerals, and wind-blown sediments.
Surface water Bodies of water such as rivers and lakes.
Topography The study of the land surface, such as mountains, hills, creeks and other features in the area.
Water table This is the boundary between saturated and unsaturated areas in an aquifer. Changes in rainfall can cause changes in the water level. Shallow wells can be installed in saturated areas, and water levels are measured in the wells.

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