An MWMO grant funded green infrastructure to capture and clean stormwater runoff and provide wildlife habitat at Xcel Energy’s new Marshall Operations Center. A variety of stormwater treatment systems are integrated into the site, along with native trees, shrubs, and prairie plants that will provide improved habitat along the Mississippi Flyway bird migration corridor. Interpretive features will offer insight about the site’s sustainable design.
Xcel Energy constructed a new 3-story, 90,000-square-foot office building on the 8-acre Northeast Minneapolis site, which is a former clay borrow area with brick manufacturing on-site that was later used as a coal ash storage area. As part of the project, Xcel Energy removed all the ash and contaminated material from the site and replaced it with clean, sandy soil with high infiltration rates. The new building would offer flexible office space and meeting rooms for Xcel Energy employees. Xcel Energy is using the project as a pilot for an internal initiative to incorporate sustainability principles into their land management.
A variety of green stormwater infrastructure is integrated into the design, including infiltration basins, structured raingardens, vegetated swales, and pretreatment structures. These features will be located throughout the site and together will remove an estimated 95 percent of phosphorus and sediment from the site’s stormwater runoff, thereby protecting the nearby Mississippi River. The stormwater features will connect with a variety of restored habitat. The redeveloped site will serve as a connection between several existing prairie and woodland habitat areas. Invasive or undesirable species will be also removed from the existing tree stand on the west end of the property. No-mow grass seed was also selected for the site to help reduce site irrigation and fertilizer needs.
Xcel Energy worked with several government organizations and the railroad to move the project forward. Tree species for the site were selected in consultation with the Minneapolis Park and Recreation Board, so as to provide a sufficient level of diversity. Xcel Energy also coordinated with Hennepin County, the City of Minneapolis, Minnesota Pollution Control Agency, and Department of Natural Resources on the design plans. The stormwater treatment systems treat runoff from the Soo Line Railroad to the north.
Xcel Energy plans to construct a walking path though the prairie, a patio area near the stormwater features, and a “gateway area” on the corner of Marshall Street NE and St. Anthony Parkway to welcome the public with bike and pedestrian connections. Onsite interpretive signage will describe and educate employees and guests on the stormwater and habitat features.