Salinity in Australia and its affect!
Salinity is the presence of soluble salts in water and soil
This includes groundwater and surface water. There are 2 types of salinity: Dryland and Wetland (also known as irrigation salinity). It’s caused by the underground water levels rising bringing naturally occurring salt to the surface. This concentrated salt that has been brought to the surface can be in many forms such as sodium chloride, calcium, magnesium, carbonate and sulphate.
Dryland salinity is caused by removing deep rooted plants, trees, shrubs and grasses and replacing them with crops and pastures that don’t use up as much water as the previous vegetation. This process causes the water tables to rise above normal bringing the salt up as well.
Wetland/Irrigated salinity is caused by irrigated water soaking through the soil and being added to existing underwater tables. This additional irrigated water causes the groundwater levels to rise. Each time the area is irrigated this salinity process is repeated. Vegetation damage, inhibited growth, bare or eroded soil, an increase in the growth of salt-tolerant plants, water logging on the ground’s surface, higher levels of salt in surface or groundwater and roads cracking or breaking up are the main problems for causing wetland salinity.
The effects of dryland salinity are:
Decline in agricultural productivity (the salt restricts the plant soaking up water preventing the plant to get essential nutrients needed to survive).
Salinisation of groundwater (both dams and aquifers) effecting water quality for humans and agricultural use.
Infrastructure damage on farms and regional towns such as water pipe, fences, railway lines, gas pipes and houses.
Land degradation problems such as wind and water erosion.
There are also social costs, such as farm bankruptcy and health problems.
The effects of wetland/irrigation salinity are:
Decreasing agricultural productivity.
Damage to farm and urban infrastructure, including irrigation equipment.
Decline in groundwater and surface water quality.
The effects of wetland salinity are similar to that of dryland salinity!
Salinity is very hard to manage as it’s expensive, management strategies may take years to have any effect and the issues are very complex.
Some ways in combating salinity can include:
Pumping fresh ground water to lower tables preventing salinity development.
Drain surface water and saline ground water to eliminate water logging and flooding. Draining the water is very expensive, hard to maintain and has difficulty disposing water without causing problems elsewhere though.
Avoid over irrigation.
Plant salt tolerant plants and deep rooted crops/plants.
Salinity is a major environmental factor in Australia as approximately 2.4 million hectares of land are affected by it and 5.7 million hectares are at risk of it.
It is prevalent in Western Australia, Victoria and South Australia. Salinity often occurs when there is little tree coverage, low points in landscape, along drainage lines and where irrigation is present.
Due to these factors farms and open areas of land are often most affected by dryland salinity, while wetland salinity is often found where soil/ground/vegetation is damaged and high levels of salt are found.
