Managing erosion control along riverbanks

The recent flooding has led to increased attention on the erosion of our riverbanks. Healthy riparian zones have vegetation that stabilises banks by filtering and trapping sediments, leading to reduced sediment in waterways. Plant roots help to stabilise banks by binding the soil and overland water flows, reducing the erosive force of the water. Vegetation also shades waterways, reducing water temperature for aquatic animals.

Erosion is dramatically increased where there is no vegetation or there are only weeds with shallow root systems to stabilise the banks. Some of the associated impacts of bank erosion include:

• Collapse of the riverbank and stripping of surface soil; • Undermining of canopy vegetation and loss of vegetation; • Deepening and widening of gullies • Poor water quality downstream from silting of the waterway; and • Damage to infrastructure.

There are a variety of ways to reduce the likelihood and severity of erosion in our waterways. Some management practices include:

• Establishing and maintaining a wide, vegetated riparian zone; • Restricting development in the riparian corridor; • Controlling weeds, especially exotic vines that can smother canopy trees; and • Protecting, planting and maintaining a diverse range of vegetation. Erosion is accelerated without vegetation to hold the soil together. Image courtesy of Local Land Services (LLS)