Flood water rushes over a road in Plymouth County.
The Memorial Day weekend storms taxed many wastewater treatment plants around the state, causing the release of untreated sewage, and prompting a warning from the DNR about possible spikes in bacteria.
DNR spokesman, Kevin Baskins, says it’s a matter of too much water hitting the systems all at once.
“It’s hard to design for an event like we’ve seen, some parts of northwest Iowa got 10 inches or more (of rain) in just a 24-hour period. And when you have that much water flowing into the facility, it’s hard to design something that wouldn’tbe cost-prohibitive that could handle that amount of flow,” Baskins explains.
While the release of the sewage will cause some spikes in bacteria, Baskins says they did a lot of testing during the flooding of 2008, and found the bacteria doesn’t stick around long.
“We saw spikes in particularly bacterial contamination, but only for very short periods of times. With the amount of water that we have flowing, and as fast as the water is flowing, it flushed through the system relatively quickly,” according to Baskins.
“Now where we would be more concerned is where water gets trapped. Either in man-made structures such as basements, or in a backflow area that doesn’t flow like a river or stream does.” He says you should always be careful about getting into any water after there has been a lot of runoff.
“Even if we didn’t have the situations that we do with the wastewater treatment plants being inundated, you would still see bacteria spikes. We’ve seen that for the last 10 years on our beach monitoring,” Baskins says. “Anytime we get rainfall, what’s on the landscape gets washed into that water body and you see at least temporary spikes in the bacteria levels — until it has a chance to kind of flow through and get some sunshine, because sunshine is something that will kill the bacteria in the water.”
Baskins says some feedlot operations in northwest Iowa faced the same water problems that the wastewater treatment plants face. He says they’ve been doing what they can to minimize and runoff and environmental impact.
“Some have basins that are full…and they are pumping into less full basins to keep other basins from overfilling. So we are seeing producers at least trying to do as much as they can given the difficult weather pattern that we are in right now,” Baskins says.
As with the wastewater releases, Baskins says the material getting into the waterways is highly diluted by the amount of water and quickly flows away.
Photo courtesy of Dennis Morrice, KLEM, Le Mars