In the past, stream restoration work has often meant planting trees and placing hard rock or log crib walls along eroding stream banks. More recently, bioengineering has become an acceptable and successful technique for river restoration. Bioengineering is the use of living materials and ecologically designed concepts to restore or enhance a degraded section of stream or a riparian zone.
Willow is a key tree species used in bioengineering efforts by the KWRC. This pliable tree grows quickly and can be propagated from cuttings. Its root growth is thick and readily holds soil materials in place and can act as a filter that keeps fine sediments from entering into streams.
In the summer of 2012 the KWRC undertook a bioengineering project to restore three heavily eroding stream banks using 3 separate techniques:
These three techniques will result in the eventual growth of mature willow trees and the site can be further enhanced by planting other species at the top of the bank and throughout the riparian area. The mature trees will provide shade to the stream and offer terrestrial habitats to other riparian dependent species.
Through this project the KWRC has tracked costs of installation and will continue monitoring the sites over the next few years to gauge success. It is hoped that our stakeholders will gain confidence in these techniques as they prove to be successful.