Photo credit: Mississippi Watershed Management Organization
The 300-acre Towerside District is located in a formerly industrial, rapidly redeveloping neighborhood. It’s the first designated “innovation district” in Minneapolis and Saint Paul focused on creative, sustainable community development. The Mississippi Watershed Management Organization (MWMO) saw a rare opportunity to manage and treat urban stormwater runoff on a district scale. The community system reduces landowner costs, implements more effective and environmentally friendly stormwater treatment, and provides public greenspace.
The Towerside system contributes to local climate resiliency. It reduces the runoff burden on nearby storm sewers. It’s also a reliable source of non-potable water for the developments and adjacent street landscaping, parkland, and community gardens. During the 2021 statewide drought, Minneapolis was under watering restrictions. However, the Towerside system distributed approximately 100,000 gallons of irrigation water. Only a fraction of the water stored in the underground cistern was touched.
The pollinator-friendly greenspace offers stormwater education through artistic installations. It’s also the heart of Bridal Veil Gardens, which connects with the city’s linked parks and trails system known as the Grand Rounds. The parkland and a shelter also provide a much-used community gathering place.
After a decade of planning and implementation, the district system now supports about $250 million in new development. However, it’s designed to be connected to future stormwater infrastructure as the area grows. The successful performance of the system demonstrates that public-private infrastructure partnerships can deliver greater public value. It also serves as a model for other district systems in the city and region, including an even larger 50-acre district stormwater system being constructed in North Minneapolis.
Barr’s design for the Towerside district stormwater management system features two large biofiltration basins. The basins collect, treat, and convey runoff to a 207,000-gallon underground cistern for more treatment. UV treatment, possibly the first application of its kind in Minnesota, allows the stormwater to be reused for food-garden applications.
Interconnected components were sized to collectively manage a 100-year storm event from the eight-acre site. The system treats the first flush of runoff before it enters the Mississippi River, benefiting the ecology of the river and river users downstream.
Design and installation maximized flexibility to accommodate future developments, infrastructure, and operations and maintenance. The busy urban setting required creative construction solutions and careful coordination with contractors from other projects—all working in the same sandbox. The cistern was designed to be easily accessible so workers can enter it for inspections, repairs, and maintenance.