In-stream stabilization techniques can be utilized as stand-alone measures or in conjunction with permanent bank stabilization techniques to prevent bank failure, achieve grade control, create riffles and restore stream sinuosity.
These techniques are an alternative to laying back steep banks where access for restoration opportunities in riparian areas is limited and increase water quality and wildlife habitat. The use of natural stone materials also presents an opportunity to improve stream aesthetics for trail users adjacent to waterways. Stabilization is to be implemented according to the appropriate design storm requirements specific to the site.
In-stream stabilization techniques include the following:
- Rock cross vanes and /or J-hook structures can be implemented to control meanders, help prevent undesirable bank failures and reduce stream migration. Also frequently referred to as bent way weirs, rock vanes point upstream and help restore the historical centerlines of streams while to creating riffle/pool/run sequences.
- Check dams are in-channel grade control structures to reduce stream velocity, minimizing future erosion and downcutting.
- Vortex stone weirs can be used to span the base of narrow streams and raise the grade of the stream bed in areas where bank confinement is causing downcutting.
Permanent erosion control measures are available in a variety of construction methods depending on the situation. These methods are intended to prevent scouring from flowing water bodies or erosion of steep slopes from storm events.