A volunteer measures between bank pins (Photo by: Jim Walter, Master Watershed Steward)
Streambank erosion is an important source of the sediment and pollutants that enter rivers and stream channels. It is a natural process that occurs when the forces exerted by flowing water exceed the resisting forces of bank materials and vegetation. Erosion occurs in many natural streams that have vegetated banks. However, land use changes or natural disturbances can cause the frequency and magnitude of water forces to increase. Loss of streamside vegetation can reduce resisting forces, thus streambanks become more susceptible to erosion. Channel realignment often increases stream power and can accelerate streambank erosion.
Streambank erosion can undercut roads, bridges and utilities and lead to expensive repairs and the need for bank stabilization. It can also significantly degrade water quality. Despite its impacts to infrastructure and stream health, streambank erosion rates are rarely monitored and the effectiveness of stream bank stabilization projects rarely quantified. We are currently utilizing trained volunteer Master Watershed Stewards to monitor stream bank erosion on several watersheds throughout Bucks County to establish baseline erosion rates. With these data, we hope to identify areas that require mitigation and evaluate the effectiveness of the treatment. The collected data will help municipalities identify problem areas and monitor progress.
Bank pins are made of rebar coated with spray paint for rust prevention and camouflage and inserted into a stream bank to measure the rate of erosion. By observing erosion over time around a grouping of these inserted pins, Master Watershed Stewards are monitoring just over a dozen sites in Bucks county. Stream bank erosion is caused by high flows which can be enhanced in urban watersheds. The resulting sediment can be harmful to the habitat of the stream. Measuring rates of erosion on stream banks can help identify stress points and places where additional monitoring is needed. Bank pins are a relatively easy way to measure change.
Want to get involved? Help us find volunteers to monitor new locations! We have relatively little data about erosion in Bucks County streams and more information can help decision-makers create positive change. The Penn State Master Watershed Steward program can provide free bank pins and training/instructions for anyone who wants to take part in this project.
Contact Master Watershed Coordinator Kathleen Connally for more information at firstname.lastname@example.org.