Navigable waters. Laws for protection and preservation of navigable waters of United States, from river and harbor act approved Mar. 3, 1899 [and acts of July 3, 1930, June 13, 1902, Aug. 18, 1894, May 9, 1900, Mar. 3, 1905. June 10, 1930, June 27, 1930, Mar. 4, 1915, Aug. 8, 1917, July 9, 1918, June 7, 1924, and July 3, 1930].