Buffers are an envelope of land beyond the river channel which is allocated to provide for erosion control and protection. This is often in the form of vegetation.

The use of planted willow buffers for river and erosion management has been a practice in development for more than 30 years. It is a proven technique to provide certainty to landowners about erosion extents from frequent flooding, and is an accepted practice. The willows operate to increase resistance to erosion along a bank edge without preventing erosion occurring altogether. In effect it slows the erosion process, meaning less area of land will be eroded if planted with willows that when compared to bare, unplanted land. The willow roots serve to bind the river bank material together.

The use of willows is reliant on them and the land they are planted on being available to erode, meaning that this land is sacrificial for the purposes of limiting erosion damage, and a buffer zone planted with willows may ‘vanish’ at any time, eroded by a flood event. This is their purpose and what they have been designed for. At times these buffers naturally refill with gravel and are replanted as the river meanders transition downstream, and at other times these buffers are artificially reconstructed by machine work and replanted.

Buffers are used as a tool which supports the River Edge Envelopes and River Bed Envelope tools.

Planted buffers are not suitable in some areas, for example they are not appropriate to use at the top of high banks where the roots cannot protect the base of the slope from erosion. They are also not appropriate in places where the erosive forces of the river are too great. In these situations, other tools may be used instead of or in addition to planted buffers.

Planted buffers in most instances currently serve only a single purpose of making land available for erosion control and protection. There have been some alternate land uses trialed to recognise potential alternate revenue streams from these parcels of land that are not available for the adjacent rural land use (usually cropping, dairy or sheep and beef). These additional revenue streams include beekeeping, and growth of willows as a fodder crop.