Soil bioengineering is the use of living plant materials to construct structures that perform some engineering function. Often, soil bioengineering is used to treat sites where surface stability and erosion problems arise. Techniques such as wattle fences and modified brush layers form small retaining walls that can be used to support failing slopes or to reduce slope angles and allow other vegetation to be established.
Live pole drains act like “French” drains to provide a preferred flow path for soil moisture and thus drain sites where excess soil moisture is causing instability. Sites where moisture sensitive surface soils are sliding can be treated with live smiles, a wattle fence shaped in a catenary curve that serves to suspend the flowing mud on the slope.
Live gully breaks can be used to control seasonal flows in gullies and thus reduce the erosive force of the water while live bank protection can be used to bolster eroding stream banks. Live palisades can be used to restore bank stabilizing riparian vegetation where land clearing has removed the natural riparian cover.
Live gravel bar staking can be used to initiate the successional processes that operate on gravel bars to eventually make them productive alluvial forests. Techniques such as live shade and live staking can be used in the enhancement of damaged riparian ecosystems.
Soil bioengineering treatments can be applied to a wide variety of degraded sites. These treatments use natural components of pioneering plant communities and thus integrate well with ecological restoration principles. Examples of the use of soil bioengineering use in restoration projects are provided from the author’s experience.
Authors: David F. Polster