70 ILCS 1815/6.6

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 40 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.