What causes salinity?
Two broad forms of salinity are primary and secondary salinity. Primary salinity is part of the Australian landscape and reflects the development of this landscape over time. Secondary salinity is the salinisation of land and water resources due to land use impacts by people. Australia as a country is geologically old and stable, with vast reserves of stored salt beneath the land surface. Our climate is drier than many other countries: meaning that it has low rainfall compared to potential evaporation. Australian native vegetation grows well in this harsh climate because it is perfectly adapted to the conditions. Much of our vegetation is perennial, with a deep root system that takes full advantage of any available water. Because of this, and because the country is relatively flat thanks to its great geological age, there is very little run-off to flush salt from the landscape back out to sea. This also means that very little water is left to escape to the deeper soil below the roots.
