The City of Oshkosh Plan Commission on May 20 voted 7-0 to approve and submit the city’s 2024 MS4 annual report to the Wisconsin Department of Natural Resources, following a presentation by Alyssa Decker, the city’s civil engineering supervisor.

Decker told the commission that MS4 refers to the municipal separate storm sewer system and that the city, because its population exceeds 10,000, is required to maintain a DNR permit. She said the city is currently operating under the prior permit (an update expected from the DNR has not yet been released). Decker summarized the city’s control measures and 2024 activities, including public outreach through the Northeast Wisconsin Stormwater Consortium and city channels, illicit-discharge screening, construction-site erosion-control inspections, post-construction BMP oversight, pollution-prevention work and maintenance of the storm-sewer system map.

Decker said a consultant screened 94 outfalls in 2024 and identified 15 potential illicit discharges with chemical or physical indicators such as detergent or oil. She said staff performed 311 erosion-control inspections in 2024 (city and private construction sites) and noted that 13 new privately owned best-management practices (BMPs) were approved in the past year; the city also inspects 31 municipally owned BMPs annually. Streets division work included sweeping 882 tons of debris and removing about 441 tons of material from inlet sumps, Decker said. She said staff and contractors also carry out fall leaf collection and winter salt-management training for crews.

Commission members asked technical questions about operations. When asked whether street sweepers reach the curb line, Decker said they should sweep the flow line and that parked vehicles can limit curb-to-curb sweeping. A commissioner who described a drainage channel near Oregon Street asked whether a nearby vegetated swale was a city storm facility and said a neighbor was depositing grass clippings; Decker said she would investigate that specific location and report back.

Decker said the MS4 annual report materials and the storm-sewer map are submitted through the DNR’s e-permitting system. The commission voted to approve submission of the 2024 report to the DNR, 7-0.

Clarifying details from the presentation included: the city’s history with the MS4 permitting program (initial permit 2007; update 2014; pending state update), the number of outfalls screened (94) and potential illicit discharges identified (15), the number of erosion-control inspections in 2024 (311), the number of new private BMP approvals (13) and the amount of material removed by street sweeping (882 tons) and inlet cleaning (approximately 441 tons). Decker said all identified illicit discharges had been cleaned up.

Speakers at the item included Alyssa Decker (civil engineering supervisor), planning commissioners who asked operational questions, and members of the public who raised local drainage observations during the public Q&A.