Streambank erosion is a dynamic and natural process as streams meander across the landscape. Since European settlement of Australia, however, in many places the rate of streambank erosion has increased markedly. There are two primary reasons for this increase. The first is extensive clearing of deep-rooted, natural vegetation from catchments for agricultural and urban development. This has resulted in rainfall moving off the land surface at a much faster rate. These increased flows put pressure on stream channels that can no longer contain flood peaks, and bank erosion (as well as bed erosion) is one result. The second factor is the widespread removal of native riparian vegetation from along streambanks, either through deliberate clearing for development, or through the combined effects of stock grazing and fire. The removal of large, woody debris (de-snagging) in many streams, sometimes to assist navigation and transport, and sometimes in the belief that this would reduce flooding, has also contributed to making streambanks unstable. Both these activities have weakened the ability of streambanks to resist the erosive forces of increased flood flows and resulted in eroding streambanks becoming a common feature in Australian landscapes.

Streambank erosion often involves the loss of valuable agricultural and recreational land. As the banks collapse or erode into the stream and are washed away, sediment and nutrient loads increase and water quality is reduced. Expensive infrastructure, such as roads, bridges and buildings, may be threatened by accelerated streambank erosion. This Fact Sheet discusses the processes by which streambanks erode, and the role of riparian vegetation in helping to slow or prevent this process.

Phragmites growing over the bank of the
Murrumbidgee River helping stabilise it against
scour. Note also the protection from tree roots
and the contrast with the vertical bank on the
outside of the bend.
Photo Ian Prosser.

The full fact sheet is available in Adobe Acrobat format:

   Fact Sheet 2 - Streambank Stability 

Topics covered

• Streambank erosion - what it is and why it occurs
• Sub-aerial erosion
• Scour
• Slumping
• How riparian vegetation helps to protect streambanks
• Using vegetation to stabilise streambanks
• Golden rules in revegetating for bank stability
• Understand why erosion has occurred
• Work with others
• Carefully select species and methods for revegetation
• Establish vegetation as far down the base of the bank as possible
• Use a range of vegetation species
• Choose suitable species
• Match vegetation to stream size
• Be careful with in-stream vegetation
• Carefully consider the role of woody debris (snags)
• Can streambanks be stabilised by revegetation?
• For further information

This Fact Sheet is the second in a series dealing with the management of riparian land.