Heavy rain Tuesday evening in the western and central portions of Duluth spurred sewage overflows at two locations in the Western Lake Superior Sanitary District system.
The largest overflow was about 5,000 gallons at the Polk Street pump station, a traditional problem area when clean rainwater infiltrates the sanitary sewer system. A small, 100 gallon overflow occurred at a manhole near lake Superior College.
The WLSSD is building a new pump station at the Polk Street site along with a new, million-gallon storage facility to capture future overflows. It's part of the combined WLSSD-City of Duluth effort to comply with a federal order to stop sewage overflows.
Peak flow to the wastewater treatment plant was more than 114 million gallons per day Tuesday, compared to the average daily flow of 38 million gallons.
Rainfall was especially heavy in western neighborhoods, including more than 3.5 inches in Scanlon. Much of the rain fell between 5 and 6 p.m.
