Combined Sewer Overflows (CSO)
What they are
Sewers that collect both storm water and sanitary wastewater in the same sewer are known as combined sewers. During wet weather conditions or heavy rains combined sewers do not have enough capacity to carry all of the storm water to the treatment plant. In this case, the combined storm water and sanitary waste water overflows untreated into a body of water, creating a combined sewer overflow.
How they affect the Rouge River
For those communities in the watershed that have CSO's, the body of water that the untreated wastewater overflows into is the Rouge River. One of the first affects of this overflow is the increased amount of bacteria that is discharged into the river. In addition, this wastewater also contains other materials such as fertilizers, pesticides, motor oil and other pollutants that are carried off the surface during rain events.
What is the solution?
Many communities within the watershed are installing separated sewer systems that collect storm water and sanitary wastewater in separate sewers. With this system, only water that runs through storm drains will reach the river. However, this water alone still carries a number of pollutants.
To find out more about CSO's and what you can do, click here for the Rouge Repair Kit.