The National Pollution Discharge Elimination System (NPDES) permit requires the Village to notify residents of the CSO event. In order for residents to obtain current information regarding a CSO event, click on the following hyperlink:
www.mwrdgc.dst.il.us/CSO/display.aspx.
What is a Combined Sewer Overflow (CSO)?
A CSO is the release of untreated waste and storm water from a combined sewer system directly into a waterway. A portion of the Village of Wilmette ’s combined sewer system east of Ridge Road is diverted to the North Shore Channel by the Metropolitan Water Reclamation District of Greater Chicago (MWRDGC) after their “Deep Tunnel” is full and can no longer accept any more sewage. The Village has no control over the diversion. A combined sewer system is designed to collect a mixture of rainfall runoff, domestic and industrial wastewater in the same pipe for conveyance to a waste water treatment plant. CSO may occur during heavy rainfalls when the inflow of combined wastewater exceeds the capacity of the MWRDGC deep tunnel and the wastewater treatment plant. The CSO outfalls to the waterway act as relief points for the excess flow in the sewers, thereby reducing the frequency and severity of sewer backups and flooding.
Why is Combined Sewer Overflow(CSO) important to me?
Although CSO may contain highly diluted sewage, they may cause temporary water quality degradation in the waterways. Contact with waterways should be avoided following the occurrence of CSOs.
Potential Combined Sewer Overflow(CSO) event areas?
The Village of Wilmette has five potential CSO location along the North Shore Channel.
What is being done to reduce the occurrence of Combined Sewer Overflows(CSO)?
The MWRDGC's ongoing Tunnel and Reservoir Plan (TARP) Project , also referred to as ‘The Deep Tunnel” was implemented to alleviate the polluting effects of CSOs and to provide relief from local flooding by providing holding capacity for 18 billion gallons of combined sewage in its tunnels and reservoirs until it can to be pumped to the water reclamation plant for full treatment. Although TARP is scheduled for completion in 2015, significant benefits have already been realized. It is estimated that since the first of the tunnels went online in 1985 until 2001, more than 578 billion gallons of CSOs have been captured and conveyed to the water reclamation plants for full treatment. Since TARP went online, the waterways have seen an increase in both the fish population and number of species present; basement and street flooding has been reduced; and there are fewer floodwater discharges to Lake Michigan . To date, more than $2 billion has been spent on the project.
Who treats the sewage? The MWRDGC receives and treats the sewage from the Village of Wilmette . The District has established a 24 hour hotline to report the dumping of hazardous material into the sewer system. This number was established in an effort to reduce the possibility of contamination of waterways, poisoned fish and wildlife, and damage to the biological process of the waste water treatment plant. The hotline number is 800-332-DUMP.
Where are the Combined Sewer Overflow(CSO) events posted? The District is developing an electronic "Address Book" containing a list of email addresses of interested parties, i.e. the previously identified stakeholders. The Address Book will be updated on an as-needed basis as other members of the affected public are identified and members of the public will be able to sign up to receive e-mail notification of CSO events by accessing the District's website (www.mwrd.org). These parties will be sent an email alert in the event of a known CSO or diversion to Lake Michigan .
Where can I get more information regarding CSO? www.epa.gov or www.mwrd.org
Wilmette Public Works