Curb-Cut Rain Garden Research

Patrick Jonker
The Plastic Creek Stewards
Patrick Jonker is a biochemistry and philosophy student at Calvin College. He is currently a sophomore. This is his first year involved with the Plaster Creek Stewards, although he intends on getting more involved with their program in the years to come.

Plaster Creek, running from Caledonia to the Grand River just north of Roosevelt Park, is known as the most contaminated waterway in West Michigan. The main problems – high E. coli levels, heavy sediment loads, thermal pollution, and excessive nutrients – are all triggered and exacerbated by stormwater runoff. Plaster Creek has for years been subject to mistreatment and neglect, a trend that the Plaster Creek Stewards is working to change. One approach Plaster Creek Stewards has taken to decrease stormwater runoff is the Curb-Cut rain garden project. During the summer of 2015 thirteen curb-cut raingardens were installed in the Alger Heights neighborhood in southeast Grand Rapids. The purpose of these rain gardens was to collect storm water runoff from adjacent roadways, allow it to percolate and become transpired into the air using the deep root systems provided by native plants. The accumulated impact of numerous rain gardens like these can diminish the amount of stormwater that reaches the creek, while also supporting increased levels of biodiversity in places where people live, work and worship. Since the initiation of this project, there have been many questions from residents about ongoing maintenance and many requests for additional gardens. Because this is a relatively novel project and many of the native plants had never been used in urban restoration projects before, we developed an experimental design to test the relative success at both a garden and species scale. Our research evaluated all 13 gardens planted in 2015 and tried to answer the following four questions: 1) Which native species survived best in curb-cut raingardens? 2) Which native species performed best in curb-cut raingardens? 3) Which gardens exhibited the greatest survivorship? And 4) Which gardens scored highest for performance? These questions were addressed by measuring multiple variables in each garden, including measurements like height of the plant, leaf number, number of stalks of the plant, number of buds on the plant, the plant’s clump width, and the plants clump length. For performance, each plant was also given a qualitative “performance rating.” We found that Wild bergamot, Ohio spiderwort, and Pennsylvania sedge had a significantly higher survivorship than average, and Wild lupine, Butterfly weed, and Nodding wild onion had significantly lower survivorship than the average. This research also showed that both survivorship and performance ratings were highest in gardens that had received a compost amendment.

Poster Division: