Heavy rain causes sewage bypasses

DES MOINES -- The heavy rainfall across the state over the weekend has resulted in a number of overflows at wastewater treatment facilities across the state.

The hardest hit areas are in western Iowa where more than 7 inches was recorded in Pottawattamie County, according to Harry Hillaker, state climatologist with the Iowa Department of Agriculture and Land Stewardship.

When wastewater treatment facilities are "bypassed," sewage is not treated before it is sent directly into a body of water.

For many wastewater treatment plants, water was coming into the facility faster than it could be treated.

"The normal daily flow for the plant at Storm Lake is 3 million gallons. On Sunday, they were pumping at a daily rate of more than 20 million gallons at one point and still couldn't keep up," said Ken Hessenius, supervisor of the DNR's field office in Spencer.

DNR design standards for new wastewater treatment systems require them to handle water in the collection system from all three of these events happening at the same time: Peak sewage flows from homes, businesses and industry; peak groundwater levels and a storm that drops 2 inches of rain in an hour.

The following communities have reported bypasses to the DNR:

Buena Vista County:

-- Albert City discharged wastewater from its treatment plant from 8:30 to 11:30 a.m. Sunday to prevent flooding at the plant. The city discharged about 700,000 gallons to a drainage ditch that flows to the Raccoon River.

-- Alta began discharging wastewater from its treatment plant and collection system to an unnamed tributary of the Maple River Sunday morning. The wastewater passed through a static screen prior to entering the stream.

-- Storm Lake wastewater discharged out of manholes and into Storm Lake from 7 a.m. to 5 p.m. Sunday. The city is also discharging wastewater to Poor Farm Creek by pumping out of a manhole and from the wastewater treatment plant's basin to Outlet Creek.

Cherokee County

-- The city of Aurelia began discharging wastewater from a lift station to an unnamed tributary of the Maple River at 5:30 a.m. Sunday. As of 7:30 a.m. Monday, the city had discharged 1.5 million gallons.

-- The city of Cherokee is discharging wastewater from a manhole to the Little Sioux River. The bypass began at 1:30 p.m. Sunday and is ongoing at a rate of 200 gallons per minute.

Clay County

-- The city of Everly is bypassing treatment by discharging from a lift station to the Ocheyedan River at a rate of 500 gallons per minute. The bypass began at 7 a.m. Sunday.

Crawford County

-- Denison is discharging wastewater from its treatment system to the Boyer River. The bypass began at 4:30 a.m. Sunday.

-- Schleswig began bypassing wastewater from its treatment system at 7 a.m. Sunday to the Little Branch of the Soldier River.

-- Westside began discharging wastewater to the East Boyer River at 7:30 a.m. Sunday. The city estimates it will discharge about 100,000 gallons of wastewater by Friday morning. The city is adding another lagoon cell to its treatment plant and working to improve manholes and sewer collection system lines.

Dickinson County

-- The Iowa Great Lakes Sanitary District began bypassing from its Triboji Beach Lift Station to West Okoboji Lake at 6 a.m. Sunday. About 2,000 gallons of wastewater bypassed treatment before the bypass ended at 12:30 p.m. Sunday. The district also discharged from a manhole to East Lake Okoboji from 10 a.m. to 5:30 p.m. Sunday.

-- Spirit Lake discharged an unknown amount of wastewater from a manhole which flowed to a storm sewer that connects to East Lake Okoboji from 7:30 a.m. until noon Sunday. The city also discharged wastewater from additional manholes to storm sewers that reach East Lake Okoboji from 7:30 a.m. Sunday to 6:30 a.m. Monday.

Ida County

-- Holstein is bypassing from a lift station and from manholes to an unnamed tributary of Silver Creek. The city bypassed less than 1,000 gallons of wastewater Friday for an hour and began bypassing again Sunday. That bypass is ongoing.

-- Ida Grove is discharging wastewater to Badger Creek from both the wastewater treatment plant and from a lift station. The city began the bypass at 2 a.m. Sunday at the plant and at 7 a.m. Sunday at the lift station.

Woodbury County

-- Hornick began discharging wastewater at a rate of 150 gallons per minute from a lift station to the West Fork Little Sioux River at 3 a.m. Sunday.