Illinois Statutes Chapter 615. Waterways § 5/11. Navigability data, etc.

§ 11. The Department of Natural Resources shall obtain all possible data, surveys, charts, high and low water marks, and river gauges, and information with reference to the navigability of any of the public bodies of water of the State, and keep the same at all times available for public inspection, and aid in extending the navigation of any of the public bodies of water of the State. Such information shall be furnished at its actual cost to any person desiring the same. Certified copies of such data shall be received in court as evidence of the facts thereby shown.