Those heavy rains in northern and eastern Iowa this weekend not only caused flooding in waterways — they overwhelmed the sewer systems in many cities and towns. The Iowa Department of Natural Resources received reports that Fort Dodge alone released over two-million gallons of diluted sewage into the Des Moines River. D-N-R spokesman Kevin Baskins says it was a common occurrence. He says anytime they get large amounts of rain it overloads the system and sewage pumps have a hard time keeping up. Baskins says the heavy load of water can do some long-term damage too. He says he knows of one case in Polmeroy where the sewage lagoon overflowed. He says in that case they’ll wait until the water recedes and they’ll check it out for damage. He says there can also be damage to pumps and other equipment in this kind of situation. Baskins says the sewage is highly diluted by the large amount of rain water and doesn’t pose much long-term risk. He says other sources of bacteria may cause more problems ins lakes and streams. He says the same rains that cause systems to overload are also washing across the landscape. He says they’ve found temporary heavy spikes in bacteria in waterways after heavy rains, because the rain runs across the landscape and washes everything in its path into the waterways. Baskins says it’s better to let the sewage pass out into the waterways than to back up in basements. He says there are some options for dealing with heavy rains. He says some cities have overflow areas that can contain the storm water and sewage until the pumps catch back up and they pump the stuff back in for treatment. He says cities are also checking to see if storm water pipes are crossing into sewer pipes. Baskins says leaking storm water pipes add to the load the sewage pipes have to handle. Storm Lake is another city that had to bypass sewage after getting four to six inches of rain. Baskins says he’s heard reports of some towns getting as much as eight inches of rain.