Agencies
Services
Overview and Scope
Since 2013, the Illinois Department of Transportation (IDOT) and the Federal Highway Administration (FHWA) have been studying a potential roadway alignment for US Route 34 from west of Carman Road to TR 111 west of Biggsville, Illinois in Henderson County. In January of 2003, a Final Environmental Impact Statement (FEIS) identified the preferred alternative for the proposed US Route 34 project from Carman Road near Gulfport, Illinois to Monmouth, Illinois. A Record of Decision (ROD) was signed on August 18, 2003. When the 2003 ROD was signed, the regulatory Mississippi River 100-year floodplain did not extend onto the landward side of the levee system. Specifically, the only areas mapped as 100-year floodplains on the landward side of the levee system were those associated with local tributaries and ponds. Since the ROD was signed, major changes have occurred in the state requirements regarding construction in floodplains, and the floodplain boundaries crossed by the US Route 34 preferred alternative also changed.
The proposed expressway will need to be elevated to the 500-year floodplain elevation as a result of modifications made to the regulatory floodplain boundaries for the Mississippi River since the ROD was signed. A Supplemental Environmental Impact Statement (SEIS) is required when significant environmental impacts not evaluated in the FEIS may occur due to 1) any change to the proposed action, and 2) new information or circumstances relevant to environmental concerns and bearing on the proposed action or its impacts for the Purpose and Need and to document new impacts resulting from the proposed action. Approximately six miles of the US Route 34 alignment selected in the 2003 FEIS and ROD, are now in an area designated as a Special Flood Hazard Area protected by Executive Order 2006-05. Alternatives must be evaluated to determine if there is a practicable construction alternative within six miles of the US Route 34 alignment in the 100-year floodplain.
