In addition to participating in cooperative investigations and studies with agencies of the various States as authorized in section 426 of this title, it shall be the duty of the Chief of Engineers, through the Coastal Engineering Research Center, to make general investigations with a view to preventing erosion of the shores of the United States by waves and currents and determining the most suitable methods for the protection, restoration, and development of beaches; and to publish from time to time such useful data and information concerning the erosion and protection of beaches and shore lines as the Center may deem to be of value to the people of the United States. The cost of the general investigations authorized by sections 426a to 426d of this title shall be borne wholly by the United States. As used in said sections, the word "shores" includes the shore lines of the Atlantic and Pacific Oceans, the Gulf of Mexico, the Great Lakes, Lake Champlain, and estuaries and bays directly connected therewith.