When the City of Saint Paul began planning the transformation of Ford Motor Company’s former Twin Cities Assembly Plant into Highland Bridge—a new mixed use neighborhood along the Mississippi River—stormwater management was a central challenge. The redevelopment project needed to protect the long-term health of downstream Hidden Falls Creek, where uncontrolled storm flows had caused erosion and ecological degradation. The city and the Capitol Region Watershed District (CRWD) sought a solution that would not only treat stormwater runoff but also support broader sustainability, habitat restoration, and public space goals for the new neighborhood.
The city and CRWD hired Barr in 2007 to conceptualize a district stormwater management system. Through detailed hydraulic and water quality modeling and a triple bottom line analysis, Barr demonstrated that a centralized system with a single open-water feature would far outperform a conventional parcel-by-parcel system. The water feature, a half-mile-long stormwater pond leading to a reimagined creek channel, would trace the historic headwaters of Hidden Falls Creek, long buried beneath the former assembly plant, and offer greater ecological, social, and economic value.
Ryan Companies US, Inc., the developer, then hired Barr to complete the final design. The new district stormwater management system directs all runoff from Highland Bridge to 10 treatment features: five large rain gardens constructed with iron enhanced sand and five underground storage and filtration basins. Together, these features remove sediment and phosphorus from stormwater before it enters the pond, preventing 28 tons of sediment and 147 pounds of phosphorus from reaching the Mississippi River each year. The pond holds all runoff from storms up to the 100-year event and reduces peak discharges to Hidden Falls Creek by 98 percent during a two-year storm—dramatically decreasing downstream erosion.
By integrating stormwater management features with parks, trails, and gathering spaces, the system conserved approximately 10 acres of developable land while enhancing Highland Bridge’s abundant open space and community amenities. Barr further supported the city by helping establish a regulatory “green infrastructure overlay district” to guide the management and cost-sharing of centralized stormwater infrastructure.
Fully operational since 2023, Highland Bridge’s district stormwater management system is the first of its kind in Saint Paul, the largest of its kind in Minnesota, and a model for 21st-century sustainable urban redevelopment.
