33 U.S.C. § 621 : Navigation And Navigable Waters — River And Harbor Improvements Generally — Prosecution Of Work Generally — By What Methods River And Harbor Work May Be Authorized To Be Prosecuted Date: 7 Mar 2017 TEXT PDF Any public work on canals, rivers, and harbors adopted by Congress may be prosecuted by direct appropriations, by continuing contracts, or by both direct appropriations and continuing contracts. (Sept. 22, 1922, ch. 427, § 10, 42 Stat. 1043.) Codification Section is from the Rivers and Harbors Appropriation Act of 1922.