The Green Infrastructure Center developed the project with urban and community forestry program coordinators for forestry agencies in six states: Virginia, North Carolina, South Carolina, Georgia, Florida and Alabama — to study how urban trees mitigate stormwater runoff. The project shows how cities can utilize their urban forests as a vital tool for managing and reducing stormwater runoff. Eleven cities and one county were selected to participate in this pilot project.
Excessive stormwater runoff accounts for more than half of the pollution in America’s surface waters and causes increased flooding and property damages as well as public safety hazards. National studies indicate that land conserved for stormwater retention and flood prevention “show an eight-to-one dollar savings ratio versus man-made flood-control structures” (McDonald 2015). Cities need to better integrate trees into their stormwater management programs.
Each community received a model they could use to determine how much water their trees currently intercept as well as how much more stormwater runoff could be avoided by planting more trees or increased if trees were lost. The study also entailed a review of each cities codes, ordinances and policies for the degree to which they maximize stormwater infiltration and reviewed their urban forest management.
This summary report includes the project’s findings, the process to create a model of the role of trees in stormwater uptake and links to the best practices audit tool to help cities reducing imperviousness and better manage their urban forest.
You can learn more about this project on our Trees and Stormwater Project Page.