Making Better Use of Rainwater at CHS Field

Water resource professionals from around the Twin Cities toured CHS Field in June.
Water resource professionals from around the Twin Cities toured CHS Field in June.

In previous lives, it was a rail yard, a coal-gasification plant, a slaughter house and a shampoo factory. Today, a parcel of land sandwiched between crisscrossing freeways and historic brick buildings in St. Paul’s Lowertown is home to the St. Paul Saints baseball team. It is also the site of one of Minnesota’s best rainwater harvesting and reuse projects, and is considered to be one of the “greenest” stadiums in the country.

When the City of Saint Paul, Saint Paul Port Authority, State of Minnesota, and St. Paul Saints partnered to purchase the land for CHS Field in 2012, it was listed as one of the top ten most contaminated sites in Minnesota due to the historic industrial uses. Before redeveloping the land, the project team had to first remove hazardous waste and polluted soils. After that, they expanded the project partnership and began to incorporate design elements that would reduce the stadium’s footprint, with a goal of using less water and energy, and creating less waste.

Trees outside the stadium are planted in special boxes filled with engineered soil which allows the roots space to grow and also helps to reduce stormwater runoff.
Trees outside the stadium are planted in special boxes filled with engineered soil which allows the roots space to grow and also helps to reduce stormwater runoff.

More than 95 percent of the original Gillette building was recycled and some materials were even used on site to create retaining walls, floors, and crushed aggregate for the ballfield drainage system. The team purchases recyclable and compostable materials for the stadium’s concessions and uses color-coded containers to keep recycling and organic waste separate from garbage during games and events. Two photovoltaic arrays generate 12% of the stadium’s energy from solar power, and the Capitol Region Watershed District helped to create tree trenches, a raingarden, and a sub-field infiltration system that filter and clean stormwater before it flows to the Mississippi River. Perhaps most innovative of all is the rainwater harvesting system, which makes use of water that falls on the roof of the adjacent Green Line operations and maintenance facility to irrigate the ball field and flush toilets.

Though it may seem common-sense to make use of rainwater that would otherwise run off into storm sewers connecting to the Mississippi River, stormwater reuse is actually a rather new technology in Minnesota. At CHS Field, a pipe connects the rooftop from the neighboring facility to a 27,000-gallon steel cistern housed in a room below the ballpark concourse near centerfield. A series of filters removes leaves and sediment from the rainwater, which is also disinfected with UV light before it is pumped into the irrigation system and toilets. The Metropolitan Council, which owns the Green Line facility, was a major partner for the project, as was the watershed district. The rainwater harvesting system cost $300,000 to install (out of a $63 million stadium project), but about half of that was due to the expense of making the room surrounding the cistern into a useable space with floor, lighting and fire protection in order to meet Minnesota building and plumbing code. The cistern can collect up to 1.3 inches of rain at a time and reduces the Stadium’s potable water use by about 450,000 gallons per year.

The water cistern is stored in a room below the field.
The water cistern is stored in a room below the field.

When you visit CHS Field, it is obvious that the stadium is a community venture. Not only were dozens of partners involved in purchasing, cleaning-up, designing and building the new space, but also it is used for a wide variety of activities in addition to Saints baseball games. Hamline University’s baseball team plays at CHS Field and the venue hosts a number of amateur and youth games throughout the year as well. The highest attendance event yet at the stadium was not actually a baseball game, however; it was the Cat Video Fest, created by Walker Art Center, which attracted 13,000 people last year. This summer, after Walker announced plans to drop the event, the Saints stepped up to continue as hosts, with a 2016 festival scheduled for August 9. CHS Field also features public art installations and an adjoining dog park, which is popular with area residents.

As communities look for ways to reduce stormwater runoff pollution and make better use of potable water resources, the Metropolitan Council expects that rainwater collection and reuse projects will become more common. In recognition of the many partners’ work to restore a former polluted brownfield and build an environmentally-friendly stadium, CHS Field was chosen as the Minnesota Brownfields ReScape Award Winner for Environmental Impact in 2015.