ANN ARBOR – An estimated 25,000 gallons of sewage overflowed to the ground surface in a wooded area just east of Hogback Road on Tuesday, the city of Ann Arbor said in a release.
City of Ann Arbor Public Works Staff were inspecting damage following a rainstorm to a city-owned infrastructure when they discovered a sanitary manhole that appeared to have a recent overflow.
The crews said there was no evidence that any sewage reached a storm sewer or watercourse.
City staff placed the manhole cover back on the structure rim after removing debris from the area.
After reviewing the rain data from the storm that happened between June 25 and June 26, staff engineers determined that numerous isolated areas located upstream of the sewer overflow received significant and intense rainfall during what is called a 100-year storm event.
City of Ann Arbor Staff notified the Michigan Department of Environment, Great Lakes and Energy, in line with regulatory protocols.