Northfield extends advisory after 1 million gallons of wastewater entered Cannon River

Northfield is extending its water advisory after a malfunction at the local water treatment plant on Tuesday.

A broken pipe at the Northfield wastewater treatment plant sent one million gallons of sewage into the Cannon River on Tuesday.

The city is warning the public to avoid direct contact with the river waters downstream from Northfield. Recent water quality testing shows decreased bacteria levels and city officials said that if this trend continues, the advisory will be lifted Friday afternoon.

Organizers at the Cannon River Watershed Partnership said while the one-time discharge was alarming, the Cannon River has had chronic water quality issues from agricultural runoff and failing septic systems.

The partnership's Kevin Strauss said the sewage will be diluted out soon.

"The flow through that region is something like 1,200 cubic feet per second," Strauss said. "So there's a lot of water going down the river all the time. So in our brains, a million gallons seems huge. In the sense of the river itself, it's on the scale of about one percent of the flow."

However, the Lake Byllesby beach downstream from Northfield remains closed as a precaution.