DES MOINES —Following a rainy Memorial Day weekend and with significant additional precipitation in the forecast for the next week, Iowans are being urged to take additional precautions around flood waters.
In addition to the more obvious drowning dangers associated with often swift-moving, unpredictable flood waters, elevated levels of bacteria and other potential contaminants may be present as well.
Over the past 48 to 72 hours, many wastewater treatment facilities around the state have been unable to keep up with the unprecedented amount of water flowing into the treatment plants. Consequently, many have had to bypass untreated sewage to keep the sewage from backing up into homes and businesses which would provide an even greater risk to human health.
People are urged to avoid ingesting or directly contacting flood waters, especially if they have cuts or abrasions that may be susceptible to infections from contact with bacteria. People with weakened immune systems should also avoid contact with flood water due to the potential contact with bacteria. Swimmers and anglers should thoroughly wash after coming in contact with water during flooding conditions.
A number of large cattle feedlots, particularly in the northwest portion of the state, are also overflowing.
The good news is that the livestock facilities have been proactive in managing their operations during a challenging weather pattern, minimizing potential environmental impacts to rivers, streams and lakes, said Gene Tinker, coordinator of the DNR’s animal feeding operations program.
“We have seen producers pump manure from one basin to another to prevent overflows. Others have been using center pivots (irrigation) and land applying manure to prevent overflows. I give a lot of credit to the producers and to DNR field staff who have been involved with training livestock operators on how to properly deal with these situations,” said Tinker.
The DNR did extensive water sampling during the floods of 2008 and found that spikes in bacteria levels and other contamination could be found in the flood water. However, the sampling also showed that elevated levels of bacteria and other contamination did not last long in areas where streams and rivers were moving swiftly.
However, elevated levels of bacteria and other contamination can remain higher in areas where flood water has been “trapped” such as basements or non-flowing backwater areas.
Sampling of public beaches in 2008 showed that bacteria levels dropped relatively quickly after flooding when water was exposed to sunlight. It is also believed that the flooding conditions also helped “flush the system” washing bacteria off the landscape and quickly downstream.
The DNR has also done past sampling of bypassed wastewater during heavy rain events and found that the environmental impacts have been sharply reduced because of the high amount of dilution that is occurring from the large amounts of water generated by the precipitation.