Sanitary District outlines MS4 stormwater work, permit timeline and local ordinance updates

Al Wallace, representing the Sanitary District of Michigan City, gave the Common Council an update on the city’s MS4 (municipal separate storm sewer) program on May 6, 2025, including inspection progress, an upcoming IDEM permit reissuance and planned local ordinance updates.

Wallace said the MS4 program exists to “manage our stormwater discharges, in order to protect public health, existing water uses, and aquatic life,” and summarized the program’s six minimum control measures required under the IDEM MS4 general permit. He told the council the permit in effect was issued in February 2021 and that IDEM is expected to reissue an updated permit in February 2026.

The presentation described recent and planned work: about 40 outfalls had been inspected during the first three permit years, with roughly 30 remaining to complete in the coming 18 months; continued inspections of construction sites and post-construction stormwater facilities; quarterly inspections of four large “aqua swirl” separators the sanitary district operates; and expanded use of GIS and a new Kintone work-order system to document inspections and generate quarterly maintenance orders.

Wallace said the city submitted the annual MS4 report to IDEM in early April and that IDEM’s review found no deficiencies. He also said the Sanitary District is on the five‑year audit cycle and expects an IDEM audit in October 2025 that will review the program activities for the past five years.

On ordinances and local implementation, Wallace said staff are finalizing updates to the city’s illicit discharge detection & elimination (IDDE), construction, and post-construction stormwater ordinance language to align with the permit and clarified the MS4 operator is the mayor. He described a proposed local permit termination checklist that would require local staff verification—among other items, 70% uniform vegetative cover—before a construction stormwater permit could be terminated locally and submitted to IDEM for final closure.

Council members asked about specific practices. Councilwoman Moldenhauer asked about permeable pavements and native vegetation; Wallace said Michigan City has used porous concrete and trial permeable pavers in limited areas and noted maintenance challenges with porous surfaces and permeable pavers (vacuuming and maintenance to avoid clogging). He said the Cheney Run and Strebeau Pond projects used native plantings and delivered both water-quality benefits and park amenities. Councilman Coulter thanked Wallace and noted long-term local engagement on watershed planning.

Wallace also described efforts to import basin and retention data into GIS, to create a construction stormwater checklist for plan reviewers, and to pursue grant funding for watershed and trail planning. He told the council the sanitary district had engaged a consultant in 2024 and hired staff in January 2025 to fill the MS4 coordinator role after the prior coordinator’s April 2024 departure.

The presentation concluded with Wallace saying staff will return later this year for ordinance workshops and will provide a broader report on combined-sewer separation options after Labor Day.

The council did not take formal action during the presentation.