55 ILCS 5/5-15014
The county board may cooperate and enter into agreements with the proper agencies of the United States Government, municipal corporations of this State, political subdivisions and persons and associations, for the formulation of plans, and for the construction of any and all improvements for the control of destructive floods, and for the conservation, regulation, development and utilization of water, waterways and water resources, or other purposes of this Division. Such agreements may assign to the several cooperating agencies particular projects or portions of projects for the purposes herein stated and may provide for joint understandings for said purposes and for contribution to execute any works agreed upon with any other of the above mentioned agencies in the State of Illinois to carry out the provisions of this Division.
55 ILCS 5/5-15014