Committee approves stormwater permit for farm expansion after debate over impervious-area rules and conservation easements

The McHenry County Planning, Environment and Development Committee voted Oct. 7 to approve a stormwater application for a rural property after staff reported on mitigation measures and the applicant’s coordination with a neighbor.

Planning staff described the case as an older violation carried forward when ownership changed and said the core issue was an increase in impervious area above the county’s 20,000-square-foot threshold for detention requirements. The owner’s property was reported in committee discussion as 49.418 acres; staff said the bulk of the impervious additions serve farm operations such as truck maneuvering and heavier traffic on compacted gravel areas.

Staff told the committee that the newly compacted gravel is effectively impervious because of low void space and high compaction; they said property-specific borings and soil reports can be used to demonstrate infiltration if owners choose that route. The committee discussed the county’s current Stormwater Management Ordinance (SMO) exemptions: an agricultural exemption up to one acre if designated, and a separate allowance of up to 5 percent of parcel area for larger properties. Members said the rules currently steer applicants toward conservation easements and detention basins but that code revisions under consideration aim to allow an alternative, tributary-area–based analysis that would consider existing conditions and flow paths.

Several members expressed frustration that owners facing SMO triggers must sometimes pay for engineering or surveys to rebut a perceived flood risk; staff acknowledged those burdens and said proposed SMO revisions intend to provide more objective, spreadsheet-like tools and staff-assisted pre-application support so farmers can evaluate options without immediately hiring engineers.

Staff reported that the property owner had worked with an adjacent landowner to install a berm along an eastern property line and that inspections did not reveal immediate flood risk to neighbors. The committee voted to approve the permit, and several members said the county should honor existing conservation easements while allowing owners to reapply under future ordinance revisions if they prefer.