GreenGrid^® Size: 3,480 ft²

Installation Contractor: WESTON Landscape

Design: MMSD

Rooftop System: Extensive

Status: Completed Summer 2003

Project Narrative: In the summer of 2003, MMSD selected the GreenGrid^® Green Roof System for its corporate headquarters building in downtown Milwaukee. The District specifically selected the GreenGrid^® System because of its easy installation, preplanted modules, use of recycled materials, and the ability to adjust and rearrange the system as needed. This green roof project was installed for the various benefits that green roofs provide. Specifically, MMSD wanted to evaluate green roofs in terms of their demonstrated Best Management Practices (BMP) for stormwater. BMPs for stormwater include various methods to reduce or delay stormwater runoff that can overwhelm sewer systems during heavy rains, an issue of concern in Milwaukee. With the growing interest in green roofs throughout the U.S., MMSD decided it would install the GreenGrid^® system and determine reductions in runoff from that part of its roof now covered with green roof compared to the portion of its roof left bare as the “reference roof.”

The MMSD green roof includes 435 GreenGrid^® 4-inch modules and 75 GreenGrid^® pavers. The MMSD landscape architect designed the green roof to incorporate a unique blend of grasses and forbs native to Wisconsin's dry prairies and dry bluffs along the Mississippi River. Among the species used were Sporobolus heterolipsis, Solidago nemoralis, and Aquilegia canadensis. Each module was planted with an average of eight plants and contains at least three plant species, giving the urban site the look of a prairie.