Watershed-Wide Solutions for Channel and Slope Stabilization in Saint Paul

In 2013 and 2014, large landslides occurred in Lilydale Regional Park in Saint Paul. This park, which is adjacent to Pickerel Lake and the Mississippi River, contains steep bluffs and ravines and was the site of historic mining activity. As a result of the landslides, the City of Saint Paul, the Lower Mississippi River Watershed Management Organization, and Ramsey County led a series of watershed studies to identify unsafe slopes and ravines. Given that the lake and river are impaired waters, water quality was also an important consideration in evaluating improvements throughout the watershed. The feasibility studies resulted in a series of recommendations that ultimately resulted in several construction projects to stabilize slopes and ravines to improve safety in the park and improve the water quality of the downstream impaired waters. The work required partnerships with upstream municipalities, Ramsey County, and State and Federal agencies. Construction activities concluded in late 2019. Portions of the park have been reopened to visitors and sediment loading has significantly decreased.

This presentation will share the opportunities and challenges of providing a watershed-scale set of solutions to address slope stability and water quality concerns in an area with complex geology. The presentation will highlight the hydrologic and geotechnical complexities and include a discussion of alternatives considered, as well as a short overview of the preferred alternatives that were ultimately constructed. This project highlighted the necessity for further study of bluff erosion throughout the larger watershed, which the Lower Mississippi River Watershed Management Organization plans to investigate to identify additional areas for future stabilization.