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Flooding results in numerous sewage bypasses

Fort Dodge plant among those overwhelmed

By ABIGAIL McWILLIAM - Messenger staff writer

While Monday’s heavy rain continues to plague local residents, the flooding also caused numerous overflows of sewage treatment systems, including the Fort Dodge plant.

The Iowa Department of Natural Resources said 27 sewage treatment plants had reported sewage bypasses because they were overwhelmed by rainwater flowing into the facilities.

The city of Fort Dodge began bypassing wastewater from three lift stations and its treatment plant to the Des Moines River at midnight Monday. The bypass is ongoing, but now only bypassing from the treatment plant.

Fort Dodge City Engineer Eldon Rossow, said Tuesday the city is still bypassing from the treatment plant in small amounts.

‘‘Most of the bypass is going to the storm-water detention pond,’’ Ross said. ‘‘The rest ultimately goes to the river.’’

Rossow said everything flowing into the river is so diluted that it is within DNR limits. It’s not raw sewage like some might think, he said.

Approximately 12 million gallons of wastewater has been bypassed in Fort Dodge.

‘‘We’re doing everything we can to avoid any bypass,’’ Rossow said. ‘‘We’re running at full capacity in anticipation for the next rain event.’’

The National Weather Service is forecasting a 40 percent chance of rain every day through Sunday for most of the state.

Elsewhere, Monday’s heavy rainfall caused storm-water retention ponds at the Koch Nitrogen facility, near Duncombe, to overflow into a storm-water ditch that flows into Brushy Creek. Koch Nitrogen is working to pump the storm-water ditch into a secondary containment tank. The DNR is investigating.

Meanwhile, the city of Humboldt bypassed wastewater from three manholes to its storm sewer, which discharges (without treatment) to the Des Moines River. The ongoing bypass began at 6 p.m. Sunday, and the amount bypassed is currently unknown. Also, Algona bypassed about 100,000 gallons of wastewater to the East Fork Des Moines River on Saturday.

In another case, rainfall as heavy as 10 inches was reported in Emmetsburg where the city had bypassed more than 2.7 million gallons into a nearby creek Monday due to the system becoming overloaded. Emmetsburg bypassed secondary treatment at its wastewater treatment facility, sending partially treated wastewater to a drainage ditch that flows to the Des Moines River. While the bypass is ongoing, 2.7 million gallons had been bypassed as of Monday morning.

Facilities are required to report bypasses caused by mechanical failures to the DNR within 12 hours of onset or discovery. Facilities do not have to immediately report bypasses from precipitation events, but must include them in their monthly operating report to the DNR.

Heavy rain can overload wastewater collection systems, which are the underground sewer pipes that carry sewage to a treatment plant. Aging or poorly maintained sanitary-sewer systems are particularly vulnerable to influxes of storm water. With the sewage pipes overwhelmed, the excess water has nowhere to go, and can backup into basements through floor drains. Bypassing can lower the water level in the collection system, keeping sewage from backing up into basements, which would present health risks.

‘‘While facilities should not have to bypass, sometimes nature gives facilities more rain than they can handle,’’ Barb Lynch, head of the DNR’s Environmental Field Services.



Contact Abigail McWilliam at (515) 573-2141 or amcwilliam@messengernews.net.