'Wet weather' sewage discharges no longer publicly reported by Iowa DNR

When workers in Iowa City damaged a sanitary sewer pumping station in July, the Iowa Department of Natural Resources (IDNR) distributed a news release state-wide detailing the resulting 30,000-gallon sewage spill into a local creek and posted details about the incident on its web site.

When the city of Bettendorf pumped an estimated 5 million gallons of raw sewage – diluted with another 3.3 million gallons of rainwater – into the Mississippi River March 10, the IDNR did not notify the media or anyone else about the discharge despite the amount of untreated sewage being exponentially larger than the Iowa City spill.

So why does the IDNR make a public announcement about a 30,000-gallon sewage spill in one community and not provide the same information about a discharge nearly 200 times as large?

The primary reason, according to IDNR officials, is the Bettendorf discharge was diluted with rainwater – which had seeped into sewer lines – likely keeping the level of pollutants below the maximum allowed by the city's discharge permit.

A secondary factor was the city is fortunate to be able to pump the discharge into a large river. The Mississippi River – flowing by at the average rate of 3.4 million gallons per second – can easily disperse and dilute such huge quantities of sewage with few concerns about health issues to residents or fish.

Dumping millions of gallons of diluted sewage into state rivers has become an acceptable practice for many years as Bettendorf and dozens of other communities experience so-called "wet weather" discharges during periods of heavy rains. The large number of "wet weather" discharges – or "sanitary sewer overflows (SSO)" in the terminology of the IDNR – is another reason the state environmental agency has opted out of publicly reporting them individually.

Like the rain infiltrating into sewer lines and overflowing into rivers and streams – the required SSO reports clog IDNR staff inboxes. So, instead of detailed reports of each occurrence in each community, the only notification from the IDNR now is a general news release noting heavy rains triggered a large number of "wet weather" sewage discharges. No mention is made of the amount of raw or diluted sewage pumped into public waterways, nor the names of cities reporting those events.

Consequently, the only way to know if Bettendorf – or other communities in the state – are pumping diluted raw sewage into local rivers is to call the IDNR, or the community's public works department.

'Wet weather' sewage discharges not subject to sampling/testing

The "wet weather" sewage discharges from cities like Bettendorf also are treated differently than smaller raw sewage spills when it comes to sampling.

A spill like the one that occurred in Iowa City in July requires sampling of the discharge and monitoring to make sure it doesn't become a health issue to people in the immediate area. In some instances, the IDNR could require clean-up of an affected area or stream, or take enforcement action against the city or sanitary sewage system operator.

"Wet weather" sewage discharges, however, are much more difficult to sample or monitor since they usually occur during heavy rains and thunderstorms and distant from IDNR field offices. The office which handles permits for Bettendorf is located in Washington, Iowa, an hour drive from the Quad Cities.

And, under current statutes and discharge permit regulations, cities are not required to perform any sampling or testing of the "wet weather" discharges. The only requirement is that the community report the wet weather pumping within 12 hours of the discharge ending to the IDNR.

As a consequence – when Bettendorf experienced its largest SSO event totaling more than 98 million gallons between April 17 and April 27 of this year – the only required report was submitted within 12 hours after the pumping ended on April 28. The report simply noted the duration and total amount of gallons of rainwater/sewage pumped into the river.

IDNR staff in 2007 and 2008 did conduct sampling of some "wet weather" discharges in Fairfield, Burlington and Washington to get an idea of the pollution impact on the affected streams. The wet weather discharges sampled by the IDNR showed that in most cases the pollution levels were within the permit limits for wastewater discharges from those communities. Those permits, however, do not set limits on E. Coli (bacteria) levels for discharges.