Phosphorus Load Reduction Using Streambank Stabilization – a Ten Year Follow Up

In 2010 the City of Princeton, Minnesota entered into a phosphorus reduction agreement as a condition of a permitted expansion to the municipal wastewater treatment facility. The City agreed to stabilize five eroding streambank sites (three sites on city-owned property and two on private property) with a goal of reducing phosphorus loading to the Rum River by 10,000 pounds annually. Phosphorus trading was a cost-effective alternative to point-source reductions of phosphorus that also addressed water quality on the Rum River which is listed as impaired for phosphorus. Stabilization treatments included turf reinforcement matting (TRM), engineered log jams, tree revetments, bank grading, and installation of native seeding and live stakes. This project is one of only three phosphorus trading sites approved within the state of Minnesota by the Minnesota Pollution Control Agency (MPCA). Construction for the project began in 2012 and was completed in 2015.
Ten years after the phosphorus reduction agreement was finalized and five years after the final project was accepted by regulatory agencies, the City of Princeton now monitors the five stabilization sites on a monthly basis during the growing season and submits an annual report to the MPCA on the condition of the sites as part of its wastewater permitting activities. City staff and WSB staff have partnered to improve stabilization and maintenance activities in order to maintain bank stability while decreasing costs to the City budget. Project team members will present on details of specific stabilization activities used, permitting and regulatory requirements, and lessons learned during maintenance and inspection activities.