70 ILCS 1825/4.1

To issue permits: for the construction of all wharves, piers, dolphins, booms, weirs, breakwaters, bulkheads, jetties, bridges, or other structures of any kind, over, under, in, or within 50 feet of any navigable waters within the Port District; for the deposit of rock, earth, sand, or other material, or any matter of any kind or description in such waters.