DICKINSON COUNTY — Heavy rainfall and power outages in northwest Iowa led to multiple wastewater discharges in the Iowa Great Lakes area this (Monday) morning. The DNR Field Office in Spencer was notified early Monday morning of a wastewater bypass occurring at a lift station just south of Manhattan Point on the west side of West Lake Okoboji.

The Iowa Great Lakes Sanitary District pumped down the lift station and hauled as much wastewater as possible to the treatment plant to minimize the bypass. Officials estimated that about 10 gallons per minute of untreated wastewater flowed into the lake. All drinking water systems and a nearby resort were notified, as well as residents in the vicinity of the bypass. Area officials report the discharge ended around noon.

At 9:30 a.m. the Field Office was notified of another bypass occurring at a lift station near Francis Sites on East Lake Okoboji. This bypass ceased around noon. The City of Spirit Lake is also bypassing their wastewater collection system to storm sewers and discharging to East Lake Okoboji. Pumps are running at two locations on the west side of upper East Okoboji to try and keep wastewater out of basements. Residents are being notified.

Heavy rainfall can overload wastewater collection systems, which are underground sewer pipes that carry sewage to a treatment plant. With sewage pipes overwhelmed, excess water has nowhere to go, and can back up into basements through floor drains.

Bypassing can lower the water level and alleviate pressure in the collection system, keeping sewage from backing up into basements, which could present health risks. DNR staff continue to monitor these situations and will provide assistance to impacted communities.  It is highly recommended people and pets avoid these areas and stay out of flooded and elevated waterways due to safety concerns.