For the acquiring of rights-of-way and property necessary for the construction of terminal railroads and structures, including railroad crossings, airports, seaplane bases, naval bases, wharves, piers, ships, docks, quays, elevators, compresses, refrigerator storage plants, warehouses, and other riparian and littoral terminals and structures and approaches to them and transportation facilities needful for their convenient use and belt line roads and highways, causeways, and bridges and other bridges and causeways, and for the acquiring of property necessary for the river development project known as the Savannah River Project Below Augusta, and for the acquiring of property necessary for the development of a harbor or harbors within this State on the Savannah River, the Authority may purchase them by negotiation or may condemn them. The power of eminent domain shall apply not only to all property of private persons or corporations but also as to property already devoted to public use.