At approximately 2:00 p.m. on Wednesday, May 8, 2019, City of Ann Arbor Public Works staff were notified of a leaking City sanitary sewer manhole in the University of Michigan Arboretum. Public Works staff immediately addressed the issue, finding the cause to be a blockage in the 8” pipe of gravel. An estimated 1800 gallons of untreated sewage was surcharged from a sanitary sewer manhole into a grassy open space in the Arboretum.
In partnership with University of Michigan staff, all cleanup activities were completed within 24 hours of the incident. The affected ground nearby was cordoned off and limed, to neutralize any bacteria that may remain on the ground surface.
After investigation, it was found that University of Michigan grounds maintenance activities damaged the manhole structure, causing an opening for gravel to enter the sanitary sewer system, thus blocking the pipe.
In accordance with regulatory protocols, City of Ann Arbor staff has notified the Michigan Department of Environment, Great Lakes, and Energy.
If you have any further questions – please feel free to contact me.
Jennifer E. Lawson, Water Quality Manager
Systems Planning Unit – Public Services Area
City of Ann Arbor | Guy C. Larcom City Hall | 301 E. Huron, 4th Floor ∙ Ann Arbor ∙ MI ∙ 48104
734.794.6430 (O) | Internal Extension X43735