55 ILCS 5/5-15011
Every such county is authorized to construct, maintain, alter and extend its sewers, pipelines, channels, ditches and drains along, upon, under and across any highway, street, alley or public ground in the State as a proper use of highways, but so as not to incommode the public use thereof, and the right and authority are granted to any such county to construct, maintain and operate any conduits, mainpipe or pipes, wholly or partially submerged, buried, or otherwise, in, upon and along any of the lands owned by the State and under any of the public waters therein; provided, that the extent and location of the lands and waters so to be used and appropriated shall be approved in writing by the appropriate State agency: And provided further, that the rights, permission and authority hereby granted shall be subject to all public rights of commerce and navigation, and to the authority of the United States in behalf of such public rights and also to the right of the State to regulate and control fishing in the public waters.
55 ILCS 5/5-15011