Steven Bergerson

The building site was a worst-case scenario: Eight acres were available for the future Minnesota Twins’ stadium, Target Field, in downtown Minneapolis, but architecture firm Populous needed a full 12 acres to build the programmed 40,000-seat stadium. On the site’s northeast side were light and commuter rails; on the southeast, a highway; and on the southwest, a viaduct. The northwest side bordered a municipal garbage burner with a freight-rail linethere was no room to expand the original acreage.

Also, the site was once a contaminated riverbed. Mortensen Construction had to drive 3,300 10-inch-diameter steel pipes 100 feet into the bedrock just to stabilize the area for building. There wasn’t even room around the site to house the supplies or cranes for construction.

Out of this disaster scene, however, Populous scored big, creating the second-ever LEED-certified Major League Baseball stadium in the countrybeating the first, Nationals Park in Washington, D.C., by two points. (Both are LEED Silver.)

For the $545 million stadium completed in January, the firm had to build from the inside out, staging the supplies and equipment on the future field. The firm also had to build inside out in form. As Populous associate principal Mike Donovan describes it, the stadium is shaped like “a beautiful mushroom.” From the air, one would see a stadium with what appears to be a 10.5-acre footprint, not the actual 8-acre footprint.

To achieve LEED, the firm incorporated a range of environmental measures. Reducing construction waste, building with recycled and locally sourced materials, and including radiant heating were straightforward. In addition, Populous got creative with high-efficiency field lighting and a rainwater filter system, which treats 90 percent of runoff, filtering it for use in washing down the seating bowl and irrigating the field. Populous also pipes in steam from the municipal burner as an energy source for heating the stadium’s water.

If situating a ball field in the middle of the urban Minneapolis-St.Paul-area has disadvantages, it also had one big, green advantage: public transportation. The light-rail lines were extended to meet the stadium, and connect with a commuter-rail line in a public transportation hub integrated into the stadium. A major bus station lies on the east corner, and fans on bikes can access the stadium via a bike trail on the south corner.

Populous topped off its achievement with a giant, white boomerang of a canopy that totals 66,805 square feet. Enclosed all the way around, the canopy roof helps reduce the heat island effect. At night it glows, reminiscent of the field’s light stands.

Target Field has essentially extended downtown Minneapolis by two blocks. But according to Populous senior principal, Earl Santee, the ballpark’s impact stretches beyond its slight size: “You can measure the ballpark in miles,” he says, “not just feet.”