Green-infrastructure BMPs enhance a pedestrian friendly plaza and manage runoff
Barr prepared a conceptual plan for incorporating linear stormwater BMPs along 11 blocks of Riverside Avenue slated for reconstruction by the City of Minneapolis. Three locations were chosen. Barr’s designs included two connected BMPs on either side of the newly aligned 8th Street to provide stormwater storage and infiltration: a stormwater infiltration basin (with a curved, concrete retaining wall and railing and a rain garden of shrubs and grasses framing the basin) and a permeable-paver plaza over a tree-trench system. A stone bench completes the pedestrian friendly plaza. The 8th Street BMPs are designed to capture and treat 0.5 inches of runoff from over two acres of nearby streets, sidewalks, and rooftops.
Barr designed two other BMPs within the Riverside Avenue right-of-way. A swale was added between the curb and sidewalk in front of Augsburg College between 21st and 22nd streets. Custom sump-catch-basin structures divert water from the gutter to the swale, where trees are planted and water infiltrates through crushed rock into the subsoil. The combination captures 0.3 inches of stormwater runoff from half of Riverside Avenue. Along 20th and 21st streets, a standard sump-catch basin drains 0.8 inches of runoff from half the street into a pretreatment sand-filter box that drains into an infiltration crushed-rock trench under the sidewalk. Barr also provided construction administration.