Milwaukee, WI
Milwaukee’s intense rain leads to 2.7 billion gallons of sewage released
Take a tour of Milwaukee’s deep tunnel
Take a tour of Milwaukee’s deep tunnel. It was designed to capture and hold excess runoff and sewer water, thereby mitigating flooding.
About 2.7 billion gallons of untreated wastewater was discharged into local waterways and Lake Michigan, according to the Milwaukee Metropolitan Sewerage District.
Last week’s torrents of rain pushed Milwaukee into its rainiest April on record. Upwards of 6.69 inches of rain fell in the Milwaukee area from April 12 to 16, according to the sewerage district’s rain gauges. Flood warnings remain more than a week later in a dozen counties.
The systemwide combined sewer overflow, initiated at 8:24 p.m. on Apr. 14, lasted about 114 hours. The wet weather also resulted in several sanitary sewer overflows in the sewerage district’s isolated-sewer system.
In a combined system, a single pipe carries both untreated wastewater and stormwater. It makes up 6% of the sewerage district’s service area, and is located entirely within the city of Milwaukee and the Village of Shorewood. In an isolated-system, sewage and stormwater flow through different pipes.
In both cases, an overflow can mean elevated bacteria from untreated wastewater in local waterways.
The estimated total volume was of the sanitary sewer overflows was 11.6 million gallons, impacting West Allis, Milwaukee, Bayside and River Hills. Specifically, these overflows occurred at:
- W. Grant Street and S. 77th Street in West Allis;
- S. 43rd Street and W. Lincoln Avenue in Milwaukee;
- S. 74th Street and West Oklahoma Avenue in Milwaukee;
- N. Broadmoor Road in Bayside;
- N. Lake Drive and East Ravine Lane in Bayside
- N. Range Line Road and Milwaukee River in River Hills; and
- N. River Road and W. Greentree Road in River Hills.
An in-plant spill also occurred at the Jones Island Water Reclamation facility as a result of the intense rainfall. However, the sewerage district said that Lake Michigan and local waterbodies were not impacted. Work on this spill is ongoing.
By federal law, the sewerage district is allowed six combined sewer overflows per year. Since 1994, it has captured and cleaned an average of 98.6% of wastewater.
Last year’s historic August flood event led to about 5.14 billion gallons of untreated wastewater being discharged into nearby waterways and Lake Michigan. It was the largest systemwide since the Deep Tunnel was built in 1993.
Since 1995, the sewerage district has invested more than $580 million in green infrastructure and flood management projects to improve the landscape’s ability to hold onto water, helping to avoid overflows.
Green infrastructure helps nature do its job by absorbing and storing rain and melting snow. It protects against flooding and excessive heat as well as improves air, soil and water quality, which can help the city better adapt to a changing climate.
Caitlin Looby covers the Great Lakes and the environment for the Milwaukee Journal Sentinel. Contact: clooby@gannett.com. Follow her on social media @caitlooby.
Caitlin is an Outrider Fellow whose reporting also receives support from the Brico Fund, Fund for Lake Michigan, Barbara K. Frank, and individual contributions to the Journal Sentinel Community-Funded Journalism Project. Journal Sentinel editors maintain full editorial control over all content. To support this work, visit jsonline.com/support. Checks can be addressed to Local Media Foundation (memo: “JS Community Journalism”) and mailed to P.O. Box 85015, Chicago, IL 60689.
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