Combined Sewer Overflows
What are they and why are they important?
To understand a combined sewer overflow, one must first know what a combined sewer is...
Combined Sewer System
When our nation's and Frankfort's sewer systems were first built years ago, they were designed to carry both sewage and storm/rainwater in the same pipes. This type of sewer is called a "combined sewer system" because sewage and storm water are combined into one pipe. Although the construction of this type of sewer is no longer allowed, there are still portions of Frankfort that are still served by a combined sewer system. Our map of Frankfort's combined sewer system shows that it serves the South Frankfort and Downtown areas.
Combined Sewer Overflows
At the time our nation's sewer systems were being built, it was common practice to include overflow points at which excess water can escape from the pipes. Since combined sewer systems capture both storm water and sewage, heavy rains can cause the amount of water entering these pipes to exceed their capacity.
Occasionally, it rains so hard that the amount of rain entering these pipes is more than they can handle. When this happens, the mixture of sewer and storm water can back up into people's homes or onto the streets. Combined sewers were built years ago to prevent backups by providing overflow points at which the excess water and sewage can be discharged from the pipes into nearby rivers or streams. When this happens, it is called a combined sewer overflow.
Here in Frankfort, we have 15 combined sewer overflow points. Our map of the combined sewer overflow locations shows that there are 13 points that discharge into the Kentucky River, one into Benson Creek, and one into Penitentiary Branch. The map also shows four CSO locations that have been eliminated.
The Clean Waterways Program and Combined Sewer Overflows
As Frankfort and other cities grew, the negative health and environmental impacts of discharging sewage and storm water into rivers and streams became apparent. The Clean Water Act helped ensure that cities would not continue to build combined sewers and their associated overflows. Even so, there are more than 700 communites nationwide and nearly 20 in Kentucky that still have combined sewer overflows. Like Frankfort, most of these 700 cities is under state and federal mandates to make improvements that will dramatically reduce both the amount of sewage in each combined sewer overflow and the frequency with which these overflows occur.