The role of green stormwater infrastructure in flood mitigation (Detroit, MI USA) – case study

ABSTRACT

Increased precipitation, ageing infrastructure, and rising surface water levels have exacerbated stormwater issues in the city of Detroit, causing combined sewer overflows and basement flooding. Green stormwater infrastructure (GSI) is now a requirement of the city as part of its stormwater discharge permit to decrease stormwater system overflows. While GSI has been shown to improve water quality in combined sewer overflows, there has been widely-varying conclusions in flood mitigation potential. This study applied a calibrated EPA Stormwater Management Model (EPA SWMM) to investigate the potential flood mitigation benefits of GSI at a neighborhood scale in the city of Detroit. Results suggest the greatest flood mitigation occurs when locating larger scale GSI (i.e. bioretention basin, bioswale, green roof) in areas that are towards the upstream end of the storm sewer system. However, smaller-scale GSI systems (i.e. rain gardens) were also shown to be effective in flood mitigation in limited cases.

KEYWORDS:

• Green infrastructure
• stormwater management
• EPA SWMM
• inland flooding
• flood simulation

Acknowledgements

We thank Natalie Lyon and William Schuster for proofreading this article and providing support throughout this project. We also thank Michigan Department of Environment, Great Lakes & Energy and Detroit Water and Sewerage Department for providing support on this project.

Credit author statement

Jamie Steis Thorsby: Methodology, Validation, Investigation, Writing – Original Draft, Visualization, Project Administration; Carol J. Miller: Conceptualization, Writing – Review and Editing, Supervision; Lara Treemore-Spears: Conceptualization, Methodology, Funding acquisition, Writing – Review and Editing.

Disclosure statement

The authors declare no conflict of interest.

Additional information

Funding

This work was supported by the Federal Emergency Management Agency and the Fred A. and Barbara M. Erb Family Foundation.