There weekend rainfall amounted to a five-year storm event, says Ottawa City Engineer Tom Duttlinger. He says the city’s storm sewers can handle up to a ten-year event. There was a lot of rain, but since it was spread over a few hours, the sewers handled it just fine with no reports of backups. The city’s been doing sewer improvements too.
The U.S. Environmental Protection Agency is requiring numerous communities, including Ottawa, to separate storm and sanitary sewers. The two channels flow separately most of the time. But during heavy rain, storm sewers overflow and the water mixes with the sanitary sewers. The dirty water backups into homes in one direction and flows out into streams in the other.