“Bioengineering” is a technique that uses structural materials along with plantings to create a natural shoreline that effectively controls erosion. It is effective because the root systems of the plants used are very extensive and work to hold rocks, soils, and other plant roots in place when exposed to erosive wave action. The greatest benefit of using bioengineering materials is long-term stability. More information and photos are available on the Indiana Administrative Code website.
Types of Bioengineering:
1. Joint plantings involve the use of native wetland vegetation with glacial stone. The vegetation is installed into the spaces between the rock where they will eventually root and sprout. Once established, the vegetation creates a root mat under the rocks. This technique can be a relatively permanent resolution to recurring erosion from high velocity wind and waves and is a common design along lake shorelines.
2. Coir logs made of coconut fiber are placed to stabilize the shoreline, large tree roots and logs may be installed to deflect water flow, and both live stakes and seeds are planted.
How does a bioengineered seawall help promote healthy lakes?
A well vegetated shoreline improves water quality by filtering nutrients and pollutants, capturing sediment from runoff and preventing shoreline erosion. Less erosion leads to clearer lake water.
Many of the plant species used in bioengineered shorelines also provide habitat for wildlife and will deter nuisance wildfowl such as Canada Geese and Mute Swans from your lawn.
- Woody plant species, which are often used in bioengineered shorelines, also help maintain the cooler water temperatures essential to some fish and invertebrate species.
What special considerations are there with a bioengineered seawall?
- A permit is required to install a bioengineered seawall.
- Fencing may be installed around the project for 1-2 years to protect young plants from deer or waterfowl.
- Herbaceous plantings should not be mowed or pruned.
- Exotic plants such as Purple Loosestrife should be eradicated from the project area.
- Properly constructed projects will be self-sustaining and require minimal maintenance.
- Bioengineered seawalls are especially effective in protecting steep and highly vulnerable shorelines.
Estimated cost: Approximately $100/linear foot.