Trout Brook Nature Sanctuary and Trail
The Trout Brook Nature Sanctuary and Regional Trail, which was developed on a 42-acre urban brownfield site in Saint Paul. The project’s key design feature was the re-creation of approximately 3,000 feet of the Trout Brook after decades of confinement within an underground storm tunnel (the Trout Brook Interceptor). Relatively novel at the time of design, the project includes three water quality treatment trains to manage stormwater from adjacent urban areas before entering the Trout Brook. The treatment train components consist of hydrodynamic separators, wet ponds with iron enhanced sand filter benches, and three new wetlands. A new restroom facility, paved and rustic trails, parking, public art, brownfield mitigation measures, and ecological restoration of the site was also completed.
The final piece of the design, years later, was the Trout Brook Lift Station and Force Main to bring baseflow water to the Trout Brook from the existing storm tunnel. Construction of the lift station and force main required two sections of pipe to be installed via trenchless methods to protect the condition of the aging Trout Brook Interceptor as well as to pass beneath an active BNSF railroad. Caisson installation was required to avoid an open excavation that would put the Trout Brook Interceptor at risk. Included in the design of the lift station and force main are a sediment removal sump and an innovative pump control system that reduces energy use and reduces suspended solids from entering the Trout Brook.
The City had been working to make the Trout Brook project a reality with the support of the local community for roughly 20 years prior to the project design. With no suitable connection to nature in the neighborhood, a group of nearby residents identified this property as a great opportunity to provide much-needed natural space and refuge.
The vision for the project also fit with the City’s and Capital Region Watershed District’s (CRWD) goals of “bringing water back to the surface.” As was identified in the planning phase, this project will serve as the first such daylighting project along what has the potential to be a corridor of multiple projects in this watershed.
This project reversed historic environmental degradation that was preventing safe use of the area by humans and wildlife alike. One of the City’s project goals was to prepare the site for recreational use by remediation of environmental impacts in accordance with guidelines established by the MPCA Voluntary Investigation and Cleanup and Petroleum Brownfields Programs to minimize risks to human health and the environment. HR Green used contaminant concentrations to determine areas that could be mixed to meet the Recreational Use Soil Reference Values at various depths. Soil that met the reuse criteria was recycled on-site, and highly contaminated or unsuitable soils were hauled offsite.
This project improved water quality, reduced human and wildlife risk from soil contamination, restored ecological diversity and addressed a pressing societal need for a safe and educational recreational space for a neighborhood in the heart of the City that was committed to making it happen.