Oregon Revised Statutes Shipping and Navigation § 777.120

(1) To the full extent the State of Oregon might exercise control or grant to ports the right to exercise control, a port has full control of all bays, rivers and harbors within its limits, and between its limits and the sea. As convenient, requisite or necessary or in the best interests of the maritime shipping and commercial interests of the port, a port may, within its limits:

(2) A port shall have the authority to engage in the control and prevention of river and stream bank erosion, and the prevention of damage from floodwater and sediment, and to make, establish, change, modify or abolish such rules and regulations to preserve natural resources and prevent estuary and stream pollution within the boundaries of the district.