Bioengineering for natural resource conservation

Bioengineering is an approach which uses living plants, often combined with structural materials, to embed live, dormant, and/or dead plant materials into soil. Variations of the term include biotechnical slope protection, biogeotechnology, soil bioengineering, and hydro-bioengineering. Combined with sound application of engineering and geomorphic principles, bioengineering can serve as a valuable tool in natural resource conservation.

Bioengineering provides the benefits of vegetation quickly and more reliably than conventional planting techniques. These benefits include bank stabilization, habitat enhancement (food and cover sources and temperature control for aquatic and terrestrial animals), purification and filtration of overland runoff, contribution of organic matter (nourishment) to land and adjacent water bodies, and aesthetic improvement.

Bioengineering is a diverse and multi-disciplinary field, requiring the knowledge of engineers, botanists, horticulturalists, hydrologists, soil scientists and construction engineers. Bioengineering can be used in many soil stabilization and erosion control situations from streambank and lakeshore protection to upland gully restoration and slope stabilization. Bioengineered restoration of flood or high water damage to streams and lakes provides a more natural-looking solution than traditional concrete structures.

The use of bioengineering methods dates back to the 12th century in China, when brush bundles were used to stabilize slopes. This century, similar techniques were used in China to control flooding and erosion along the Yellow River. In Europe, especially Germany, bioengineering methods have been used for over 150 years. The use of bioengineering in the United States started in the 1920s with streambank stabilization, timber access road stabilization and slope restoration as common applications.

Advantages of bioengineering solutions are: 1) low cost and lower long-term maintenance cost than traditional methods; 2) low maintenance of live plants after they are established; 3) environmental benefits of wildlife habitat, water quality improvement and aesthetics; 4) improved strength over time as root systems develop and increase structural stability; and 5) compatibility with environmentally sensitive sites or sites with limited access.

Limitations to bioengineering methods include: 1) the installation season is often limited to plant dormant seasons, when site access may be limited; 2) the availability of locally adapted plants may be limited; 3) labor needs are intensive and skilled, experienced labor may not be available; 4) installers may not be familiar with bioengineering principles and designs; and 5) alternative practices are aggressively marketed and often more widely accepted by society and contractors.