McHenry County committee hears progress on stormwater detention revisions and MS4 permit changes

McHenry County Stormwater Committee members heard updates on proposed stormwater detention code amendments, a new watershed mapping project and evolving requirements in the state MS4 permit at a committee meeting. A county staff member said the items are moving toward more detailed review in January and that staff will return with comparative examples for subdivision development.

The discussion focused first on proposed revisions to the county's stormwater detention regulations. A county staff member said the technical advisory committee requested that staff use a subdivision development as an example to compare how the existing rules would affect detention versus how the proposed amendments would. "The TAC has requested that the staff formally use a subdivision development as an example to show a comparison between how the old regulations would affect the detention and and everything that goes with that versus how the new proposed, amendments, would affect it," the staff member said. The staff member said the example is intended to show whether the proposed amendments adequately address both small and large developments and that staff are not currently proposing acreage thresholds such as a "10-acre" cutoff.

Committee members raised specific topics staff expects to return with, including how the amendments would treat conservation easements and drain tiles. The staff member said the draft seeks to "eliminate that requirement" for conservation easements as part of the proposed changes and that drain-tile issues remain part of the discussion but have not yet been specifically resolved.

Committee members were also briefed on a watershed planning project. The staff member said the county completed a kickoff meeting and is working toward producing a full map of the Coshuaqui River watershed and a mileage estimate of streams in the basin; staff expect to present more detailed work in January.

The committee received an update on the current revision work around the MS4 municipal stormwater permit. The staff member said Lake County staff are maintaining a working, redlined document comparing the old permit to proposed changes and that some changes being discussed would require MS4 communities to increase recordkeeping and inspections. "Some of the highlights are that we at any MS4 community municipalities included, we will need to do inspections on our facilities. So, quarterly inspections, 1 dry weather, 1 wet weather, anywhere there's operations," the staff member said. The staff member specifically identified facilities such as the county sheriff's garage and "Bailey High" as examples of places likely to require inspections under the proposed language.

Staff said some wording in the working draft (for example, a sentence saying "you need to inspect all catch basins") appears broader than intended and that county and municipal staff are seeking clarifications with Lake County and the permit authors. The staff member and "Scott" said they expect to attend an October meeting to learn more about final permit expectations and to report back to the committee. Staff also said they are evaluating a cartography/GIS tracking system to record inspections and reduce the extra staff time that increased inspections would require.

Committee members did not take formal action on the detention amendments or MS4 permit changes at this meeting; staff indicated a goal of returning with more detailed comparison materials and recommended next steps in January.