Section 3710.20 Development Standards

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Illinois Administrative Code › Title 17 › › Part 37100 › Section 3710.20 Development Standards

This text was captured on Aug 14, 2026. It is a snapshot, not a live feed, so check the official code before relying on it.

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TITLE: 17: CONSERVATION

CHAPTER I: DEPARTMENT OF NATURAL RESOURCES

SUBCHAPTER h: WATER RESOURCES

PART 3710 FLOODPLAIN DEVELOPMENT REQUIREMENTS FOR STATE OWNED PROPERTIES

SECTION 3710.20 DEVELOPMENT STANDARDS

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

, 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.

This is a copy of a public record, reproduced as it was published. It is not legal advice, and it may not be the version a court would rely on. Check the official source before you cite it.

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