Section, acts July 25, 1912, ch. 253, § 1,
37 Stat. 222; July 3, 1930, ch. 847, § 3,
46 Stat. 946; Oct. 17, 1940, ch. 895, § 3,
54 Stat. 1200, related to removal of temporary obstructions and to minor improvements in navigable waters. See section
603a of this title.