400,000 gallons of sewage leaks into Ann Arbor creek

Thursday, April 7, 2016 - 5:04pm

The city of Ann Arbor has contacted the Michigan Department of Environmental Quality for the second time this year with concerns about contaminated city water sources. At the heels of an investigation regarding a plume of dioxane a carcinogenic chemical that has made its way into the Huron River, an Ann Arbor Public Works crew member discovered a sewage overflow into Malletts Creek Wednesday morning.

Though Public Works had already restored the pipe, it is estimated that close to 400,000 gallons of sewage have overflowed into the creek over the past two weeks. The overflow was discovered in a sanitary sewer manhole near the intersection of Washtenaw Avenue and Huron Parkway and is believed to have been caused by roots that had grown through the sewer pipes and thus blocked the sewage flow.

Water Quality Manager Jennifer Lawson said despite the volume of sewage added to the creek, the city does not forsee any health concerns due to the relatively slow flow from the pipe.

“From a public health and safety standpoint, there is no concern. It was a relatively small amount over a long period of time,” Lawson said. “Forty-thousand sounds like a lot but it was over a few weeks so it’s like a garden hose flowing into the creek. But it’s not something you want to see in any urban sewage system.”

City Councilmember Sabra Briere (D–Ward 1) said these occurrences happen frequently both on public and private lands despite efforts to avoid them through constant cleaning and checking of underground pipes.

“The plan is always to avoid these overflows," Briere said. "It is difficult for us to anticipate where there will be a problem. We have invested significantly and will continue to invest in our infrastructure, which is what we have to do."

According to a statement released by the city, the overflow will not affect those using the Huron River for recreational purposes due to how the sewage will be diluted. Similar assurances have been made regarding the dioxane plume. The state has recently stepped forward to assume more responsibility in cleaning up the plume by tightening its standards of how much dioxane can be permitted within drinking water.

Lawson said there are no communities that will be impacted by contaminated water because the contamination is downstream from the plant that draw water from the Huron River, the watershed Malletts Creek is a part of, and that there are no plans as of now to clean up the river due to what she referred to as the scale nature of the small influx of sewage.

“There are no intentions to clean up because (the sewage) is gone. There are maintenance activities that will continue,” Lawson said. “The city has 362 miles of sanitary sewage pipes and this was an area we haven’t checked recently. It’s on the watch list now because of all the trees in the area.”