Michigan Avenue Engineered Rain Gardens
The City of Lansing’s Go Green! Go Lansing! Initiative focuses on bringing together and promoting various local environmental projects and programs. Installed in the downtown area and a first for Michigan, the engineered rain gardens demonstrate how green infrastructure can function in an urban environment. These beautiful plantings help improve the water quality of the Grand River.
Completed in conjunction with sewer separation work and streetscape enhancements, the rain gardens were included in an overall streetscape plan designed to address stormwater quality and to demonstrate low impact development techniques within the city.
The goals of this unique retrofit included beautifying the corridor, treating the “first flush” of runoff, educating the public, and providing a pedestrian-friendly environment. The rain gardens also help attenuate peak flows for approximately 90 percent of rainfall events, increasing available capacity in the storm sewer system.
Tetra Tech was the prime consultant responsible for the entire design, including hydraulics, structure, plant and soil selection, interpretive signage, and maintenance guidance. The most significant challenge was designing around existing utilities and maintaining suitable storefront access during and after construction. Additional challenges included pedestrian safety, cost containment to secure 100 percent grant financing as stipulated by City Council, constructability, stormwater pollutants, aesthetics, and maintenance.
To monitor the effectiveness of its engineered rain gardens, which will not be watered or treated with fertilizers or pesticides, the city will be evaluating components of this project for years to come, including:
- Plant and tree survival rates in harsh conditions (periodic flooding, drought, road salt)
- Performance of the soil mixture
- Effect on downstream storm sewer hydraulics
- Solids removal (sump cleaning requirements and trash collection)
- Public perception
Tetra Tech helped the city coordinate ongoing maintenance and watershed stewardship education with the community and facilitated a partnership with Downtown Lansing, Inc. business district to develop a volunteer-based rain garden upkeep program called Adopt-A-Spot.
- City of Lansing’s rain gardens demonstrate the viability of treating stormwater runoff in an urban, cold climate setting
- Monitoring helped validate the effectiveness of the rain gardens
- Tetra Tech helped the city engage the public during each phase of the project
- Thoughtful engineering achieved an aesthetic feature for the public to enjoy
- The rain gardens have brought national attention to the city’s use of green infrastructure