Macon County, IL Environmental Rules: Boat Dock Permits (2026)

§ 151.06 sets the baseline rule for any floodway in unincorporated Macon County, including the floodway along the Sangamon River, Lake Decatur, and the county's mapped creeks: no development can go forward if it would, combined with existing and anticipated development, increase flood heights or velocities or threaten public health and safety. Rather than making every small project run that no-rise analysis from scratch, the chapter lists specific activities the county already treats as meeting the standard, and a minor boat dock is one of them, provided it meets the conditions the Illinois Department of Natural Resources' Office of Water Resources attaches to its Statewide Permit Number 5. Other listed activities on the same presumed-compliant list include bridge and culvert crossings, aerial utility crossings, bank stabilization, and accessory structures on existing residential buildings, each tied to its own numbered IDNR/OWR statewide permit.

A dock project that cannot meet the Permit Number 5 conditions does not automatically fall outside the county's rules; it just loses the presumption. Under § 151.06(B), that kind of development can still go forward only if IDNR/OWR has issued its own permit for the work, or has confirmed in writing that no IDNR/OWR permit is required, or if enough engineering data has been submitted to and approved by FEMA to revise the flood map and base flood elevation to account for it. Because a floodway dock is still 'development' under the chapter's definitions, it also needs the § 151.05 development permit from the Planning and Zoning Administrator before construction starts, on top of whatever state or federal sign-off it needs.