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Water and other liquid refuse flowing through the miles of sewers in Oakland County flow downhill. So, when more than five inches of rain fell during a three-hour period in August across southeast Michigan, more than two billion gallons of partially treated sewage also traveled downhill, journeying from southeast Oakland County into the Red Run Drain in Macomb County. It was much more than the system could handle, with all local systems overflowing, flooding sewer systems designed to capture the overflows, as well as roads, highways, and thousands of homes and basements.
The overflow was just one of more than 35 that originated in Oakland County that was recorded by the the Michigan Department of Environmental Quality (MDEQ) during 2014. In total, more than 2.4 billion gallons of storm water, sewage or partially treated sewage that originated in communities in Oakland County and later entered area surface land or waters rather than their targeted treatment plants. However, state and county water resource managers say efforts to control the number of sewage overflows, as well as the water quality of them, has vastly improved from years past.
Sewer overflows are a situation where mostly untreated sewage is discharged into the environment before it has been able to reach its appropriate treatment facilities. Wet weather overflow is the reason when it's caused by unusually heavy rainfall, either from the infiltration or inflow of excessive storm water into sewer lines during a heavy rainfall; because of a rupture in a sewer line; or the breakdown in a pumping station due to a power failure.
Of the more than 2.4 billion gallons discharged from area sewers, all but about 14 million gallons had been partially treated before being released into the environment during 2014. While still a tremendous amount of water, compared to the amount of water processed by sewage systems, it was a drop in the proverbial bucket. Of the about 14 million gallons, more than 10 million gallons of the overflows during this year contained diluted sewage from combined sewerage overflows, or a mixture of raw sewage and storm water.
Sewer systems throughout Oakland County primarily funnel both storm water and sewage to their required locations without any hitches. Yet the sewer overflows which do occur throughout Oakland County happen because the designs in the systems, which developed during its earliest years in the southeastern portion of the county, prior to the 1940s, actually lend themselves to more overflows during heavy rain events. That's because the majority of the sewer system in the area are part of a combined sewer system, meaning they carry both storm water from local catch basins, as well as sewage from people's homes and local industry. After the 1940s, newer communities were developed with separate storm water and sanitary sewer systems....continued on page 2