Kurt Leuthold, PE, LEED AP, Vice President and Senior Civil Engineer, Barr Engineering Co.

Christine Baeumler, Artist

Lois Eberhart, City of Minneapolis Public Works

Track: Applied

LID benefits can go much further than improving hydrology. This presentation will describe two innovative LID applications in Minnesota that provide a variety of social benefits including green public spaces, aesthetics, educational opportunities, and enhanced habitat.

The 37th Avenue Greenway

For many years the Folwell neighborhood of Minneapolis had been plagued by frequent flooding during moderate to large rain events, resulting in property damage and frustration for residents.  Since increased stormwater conveyance was not an option to alleviate flooding, flood storage had to be provided in the dense, urban neighborhood. This challenge created the opportunity for solutions that blended traditional stormwater management with low-impact design alternatives.

Through a series of design charettes and neighborhood meetings, the concept of converting six blocks of 37th Avenue North to a greenway was developed.  The greenway allowed for underground flood storage and above-ground biofiltration basins with iron enhanced sand to remove dissolved phosphorous.

37^th Avenue North, bisected the flood prone 50-acre watershed.  Precast concrete box culvert sections—the largest being 18 feet wide and 10 feet high—were squeezed into the right-of-way and provided the underground flood storage.  Almost 1,400 lineal feet of underground boxes now protect homes from a 100-year flood event.

In addition to the flood control benefit, the greenway provides a water quality benefit. The project treats stormwater through iron-enhanced biofiltration basins constructed along the greenway.  Runoff is diverted to the eleven biofiltration basins that remove particulate and dissolved phosphorus, metals, debris, and sediment before the runoff reaches Crystal Lake.

The project was constructed in 2011 and has become a significant amenity to the neighborhood, creating open space that is heavily used by local residents for recreation and transportation. The completed greenway benefits residents and the traveling public by reducing flooding, reducing impervious surfaces, improving water quality, and enhancing public space.

Tamarack Bog Rooftop

We have drained our urban and rural land for the purposes of habitation, industry, and agriculture.  Wetlands, bogs, and swamps have often been considered wastelands to be filled and reclaimed for development.  Wetlands, however, perform a vital function in that they not only capture nutrients and sediment before it reaches aquatic systems, but also provide essential habitat for a variety of species.

Barr Engineer Kurt Leuthold, Barr Ecologist Fred Rozumalski and artist Christine Baeumler collaborated to create a green roof tamarack ecosystem at the entrance of the Minneapolis College of Art and Design for the Northern Spark Art Festival and McKnight Visual Artist Exhibition. The Tamarack Rooftop Restoration of a bog ecosystem above the entryway to the MCAD main gallery calls attention to these fragile and unique ecosystems as well as present an artistic reimagining of green roof infrastructure. The project also is meant to remind residents how we might "reconstitute" the landscape by capturing water where it drops.

The demonstration project replaced a flat 16’x24’ roof . Previously, the roof was covered with rock ballast and drained through a scupper on to a concrete plaza. A 265 gallon aesthetically designed cistern collects runoff from the roof and it is recycled back to the roof using a solar pump system. While there will be some water quality improvement, the main purpose is to educate people about the issues of water quality and tamarack ecosystems. The project was installed in May of 2012 and the bog plants and trees are thriving.  Runoff capture volumes and losses due to evaporation have been monitored.