Section 3710.20  Development Standards

All State development activity must first comply with and obtain required permits pursuant to 17 Ill. Adm. Code 3700, 3704, and 3708. After compliance with 17 Ill. Adm. Code 3700, 3704, and 3708, all development activity located in a floodplain, which includes both floodway and flood fringe, shall comply with all requirements of 44 CFR 60 as effective on January 1, 2025 and does not include any later editions or amendments. This Part applies to State development on both new and existing construction. The following are additional standards to the requirements of 44 CFR 60 that all State development activity must also comply with:

a)         All new, substantially improved, or substantially damaged structures must have the lowest floor, including basements, at or above the flood protection elevation.

b)         Critical facilities that are new, substantially improved, or substantially damaged must have the lowest floor, including basements, elevated or structurally dry floodproofed to the 0.2% annual chance flood elevation when delineated on the FIRM or three feet above the BFE, whichever is greater.  Adequate parking shall be provided for staffing of the critical facilities at or above the BFE or 0.2% chance flood when delineated on the FIRM, when defined. 

c)         For all projects involving channel modification, fill, or stream maintenance (including levees), the flood carrying capacity of the watercourse shall be maintained. In addition, the State agency performing the development activity shall notify communities, that are both adjacent to the impacted watercourse and adjacent to the project, in writing thirty days prior to applying for a permit for the alteration or relocation of the watercourse. A copy of this notification shall be included with the permit application.

d)         If the proposed development activity modifies the FIRM, then the agency that is applying for the permit is responsible for submitting an application to FEMA for a formal determination to change the map. This process is done through the Letter of Map Change request and includes Letter of Map Amendment, Letter of Map Revision, and the Conditional Letter of Map revision.