Combined Sewer Overflows

Prior to the Clean Water Act, it was common practice to construct combined sewer systems,designed to collect rainwater runoff, domestic sewage and industrial wastewater in the same pipe. In dry weather or during small storms, combined sewer systems transport all of the wastewater to the wastewater treatment plant, where it is then treated and discharged to the receiving stream, which in Lafayette is the Wabash River.

During periods of heavy rainfall or snow-melt, however, the wastewater and stormwater runoff volume in a combined sewer system can exceed the capacity of the sewer system or the treatment plant. In these cases, the system is designed to over-flow occasionally and discharge excess wastewater and stormwater directly into nearby streams, rivers or other water bodies.
Combined sewer overflows (CSOs) are a major water pollution concern for the approximately 900 cities in the United States that have combined sewer systems. This includes our own Lafayette, which currently has 11 overflow points permitted by the Indiana Department of Environmental Management.

Taking Action for a Better Environment
In 2000 Lafayette began a 4-year $60-million upgrade and expansion of the wastewater treatment plant. This will increase wet-weather-flow treatment capacity from 22 million gallons a day (mgd) to 52 mgd. The added capacity, along with optimization of plant processes and procedures, will enable the plant to treat additional flow, thereby reducing the number and volume of the CSOs in the community.
Plans for a Brighter Future
Lafayette developed a CSO Long Term Control Plan (LTCP), including the development and implementation of a CSO Operational Plan. The LTCP also requires preparation of a Stream Reach Characterization and Evaluation Report (SRCER) to characterize the collection system and Wabash River.

The SRCER involves flow monitoring, along with preparation and calibration of a computer model of the collection system and Wabash River. It also incorporates CSO and river sampling. In addition, the City is developing CSO control alternatives and conducting a financial capability analysis for the LTCP.

You Can Help
The Wabash River provides enjoyment through fishing, boating and nature watching, and the City of Lafayette is committed to enhancing the quality of the river to support these recreational uses. You can be part of the solution. By understanding the system and staying informed along the way, you can help your government make the best decisions on this serious and complex issue. Your participation is vital to ensure that future generations will be able to enjoy clean waterways too.
Keeping You Informed
The City's Water Pollution Control Department is in full compliance with all federal and state regulations regarding the treatment of our city's wastewater. The department's aim is to educate about the most important water process issues affecting your environment.