While salinity processes in our catchments are linked, it is useful to look at different types of salinity. It is the build up of salt in the soil, usually as a result of a rising watertable. Evaporation of saline water at the soil surface tends to concentrate salts to the point where they affect the environment. The salt near the soil surface makes it harder for plants to take water from the soil and eventually they die from dehydration. This accumulation of salt usually results in the death of native vegetation as well as introduced pastures and crops.
Bare areas result, which become a soil erosion hazard.
Salt crystals can often be observed on these bare areas. The salts can be dissolved by rainwater and washed into nearby watercourses, causing river salinity. A less common form of dryland salinity is caused through soil erosion exposing saline subsoil. Erosion as a result of salinity can also contribute sediment to rivers and streams causing further decline in water quality. In rural areas, dryland salinity associated with rising watertables is often caused by the loss of deep-rooted perennial trees, shrubs and grasses.