Elgin, IL Environmental Rules: Flood Elevation Requirements (2026)

01. A of the Kane County Stormwater Management Ordinance and FEMA's current Kane County FIS and FIRMs. If a party disputes the mapped data, that party must finance the detailed engineering study needed to produce better data and submit it to FEMA and the Illinois Department of Natural Resources, Office of Water Resources, before developing the site. 020 amends the underlying county ordinance's site runoff storage requirements: detention facilities must carry a minimum of two feet of freeboard above the base flood elevation around their perimeter, except at the overflow structure, and a two-foot rise above the base flood elevation cannot damage the facility.

The same section sets a one-foot minimum freeboard on any overland flow path regardless of the service area's size, and requires open channels in a major drainage system to carry a minimum two-foot freeboard while limiting the product of maximum velocity and depth during the base flood to four or less. Establishing a BFE is mandatory in an A Zone for any new subdivision or development of fifty lots or five acres, whichever is smaller. The city engineer administers the program as the 'administrator' under section 104(2).