Biological soil crusts
There are incredibly important communities of living organisms beneath our feet that most people are completely unaware of - the biological soil crusts.
Erosion occurs when the soil crust and its cover of vegetation is damaged.
The soil crust is made up of lichens, leaf litter and soil invertebrates that together protect the soil surface and increase its ability to absorb water.
The poor placement or design of tracks, dams and infrastructure, over-grazing and the compaction of the soil, often caused by the action of hard-hooved animals, and vehicles are major causes of erosion.
With no vegetation cover to slow down its movement, water that would normally soak into the soil can run-off, washing more soil away and creating new drainage lines.
Silt traps
Simple silt traps can be created by filling erosion gullies with tree branches to slow the flow of water over the ground and catch waterborne soil particles and seeds.
Leaves eventually drop off the branches also helping to trap seeds, soil and organic matter and over time the area begins to stabilise as the soil is held together and new plants establish.
Similarly, simply cutting some bands into areas of compacted soil can help reduce water run off and allow sediment and water to pool, encouraging new plants to establish.
The seeds of plants caught in silt traps quickly germinate and help to further slow the movement of water and stabilise the soil.
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Erosion gully filled with a sediment trap at Nardoo Hills.
Earthworks
Major earthworks are sometimes needed to remove levy banks or dams that disrupt the natural flow of water, or to repair serious erosion gullies. The Gungoandra Creek rock weir and fish way on Scottsdale Reserve is a great example.
Restoring the natural flow of water across the land surface helps to return water to creeks, rivers and natural aquifers and nourishes the soil and native habitats.
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8 individually placed rocks
Erosion control case studies
