Residential Rainscaping: Analysis of Residents’ Participation in Rain Garden Programs and Stormwater Management in the City of Ann Arbor, Michigan

Annual precipitation in the City of Ann Arbor, Michigan is increasing along with population, impervious surface, and stormwater runoff. Nearly half of the land in the city is owned privately by residents, so as a result, property owners hold a great deal of responsibility for understanding the importance of stormwater management, taking action on their properties, and following best practices for stormwater infiltration.

Washtenaw County Water Resources launched rain garden programming in 2005 to provide resources and information to help encourage residents to manage stormwater on their property by installing rain gardens. The rain garden programming is seemingly successful, yet there has been no formal research to date that has evaluated the program's long-term effectiveness.

My professional project has three parts. The first is an analysis of the spatial distribution of rain gardens by subwatershed (creekshed). Findings help inform where future efforts for program outreach and expansion should be targeted based on the goals of increasing coverage in neighborhoods with either fewer rain gardens per residential area, fewer rain gardens per impervious surface area, or that have the greater impacts on water quality and stormwater quantity. The analysis revealed three options for priority locations for program expansion: (1) to have the largest number of rain gardens relative to residential area, focus on Fleming Creek, Traver Creek, and Lower Middle Huron; (2) to have the largest number of rain gardens relative to impervious area, focus on Fleming Creek, Traver Creek, and Mallets Creek; and (3) to offset stormwater runoff in areas with the greatest water quality impairments, focus on Allen Drain, Malletts Creek, Millers Creek, and Swift Run.

In the second part of the project, I analyzed responses to a county-wide survey conducted in January 2025 by the Washtenaw County Rain Gardening Program with support from the University of Michigan School of Information. The survey responses informed the design of the interview questions for Part 3 of my project.

In the third part, I interviewed several of those who had responded to the 2025 survey and found similar themes across the survey responses and interviews. Respondents are dealing with water-related problems in their yards or homes, yard aesthetics are important, and rain gardens are growing in popularity. Lack of time, the difficulty of manual labor, and invasive species are common challenges. Rain gardeners are looking for opportunities for continuing education, community learning, and support with garden installation. Rain gardens in this project are in good condition. Supporting these and other existing rain gardens to help ensure long-term effectiveness will be important, as will increasing program participation to increase the number of gardens around the city.