Erosion is the wearing away of the land by flowing water, rainfall or wind.
It is a natural process that results in the movement of soil and organic material from one place to another. It can occur rapidly or over a long period of time.
Erosion of the Australian continent has resulted in a low, weathered landscape with relatively infertile soils. Soil erosion can be hastened by extreme events such as fire, drought, flood, over-grazing and loss of vegetation cover.
The loss of bared topsoil to wind and water erosion and the formation of washout gullies has resulted in the loss of valuable farming land and a degraded environment.
Floodwaters carrying sediments and organic material create fertile plains where the flow is slowed enough for the nutrient-rich silts to be deposited. Riverine wetland ecosystems also benefit in this way from flood events.
The rate of erosion can be slowed by the adoption of sound land management practices.
How does it affect you and your catchment?
The loss of soils, particularly the nutrient-rich topsoil, is an important issue for land managers.
Areas prone to erosion may be found over every land class but the most sensitive are riparian areas, drainage lines, slopes, livestock focal points (watering points, feedlots etc.) and cultivated land.
Wetlands and meandering streams serve to slow water flow and filter out sediments. A river system with its associated wetlands intact will trap more silt and retain more water in the catchment for longer.
The riparian zone should provide a haven for wildlife in times of drought. This area takes the high water flow during periods of flood and the silting of infrastructures on the floodplain should be avoided.
Excessive silting in dams and watercourses may lead to lower water quality and toxic algal blooms.
The loss of soil by erosion can be a highly visible sign of environmental degradation. Soil conservation measures have long been recognised as essential for sustainable land use.
Management Options
- Erosion-prone areas should be managed differently from adjoining, lower-risk land classes. This is particularly important for riparian areas and cultivated land.
- Native vegetation in and around streams and wetlands should be conserved.
- Minimal tillage is an established method of maximising cropping production while minimising the potential for erosion.
- The maintenance of perennial pasture species provides more permanent groundcover than annual pastures.
- Overgrazing of livestock should always be avoided. Feral herbivores (rabbits, hares, goats, deer) should be controlled.
- Farm forestry or revegetation using native species should be considered for land where grazing results in erosion. This will also improve ground and surface water quality
NOTE:
Sourced from Adelaide & Mount Lofty Ranges Natural Resource Management Board