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Title 33, Navigation and Navigable WatersRelease 119-102

§403a Creation or Continuance of Obstruction of Navigable Waters

Title 33 › CHAPTER 9 — PROTECTION OF NAVIGABLE WATERS AND OF HARBOR AND RIVER IMPROVEMENTS GENERALLY › SUBCHAPTER I — IN GENERAL › § 403a

Last updated Aug 21, 2026|Official source

Summary

You must not build anything that blocks the flow or use of waters the United States controls unless the law specifically allows it. Keeping such a blockage in place is also illegal, except for bridges, piers, docks, wharves, and similar business structures. Every week the blockage remains counts as a separate crime. People and companies who make or keep these unlawful blockages commit a misdemeanor. If convicted they can be fined up to $5,000, jailed up to one year (for people), or both. A federal court can order the blockage stopped and removed in any district where it exists or is threatened, and the Attorney General can start those court cases.

Full Legal Text

Title 33, §403a

Navigation and Navigable Waters, Source: USLM XML via OLRC

The creation of any obstruction, not affirmatively authorized by law, to the navigable capacity of any waters, in respect of which the United States has jurisdiction, is hereby prohibited. The continuance of any such obstruction, except bridges, piers, docks, and wharves, and similar structures erected for business purposes, whether heretofore or hereafter created, shall constitute an offense and each week’s continuance of any such obstruction shall be deemed a separate offense. Every person and every corporation which shall be guilty of creating or continuing any such unlawful obstruction in this act mentioned, or who shall violate the provisions of the last four preceding sections of this act, shall be deemed guilty of a misdemeanor, and on conviction thereof shall be punished by a fine not exceeding five thousand dollars, or by imprisonment (in the case of a natural person) not exceeding one year, or by both such punishments, in the discretion of the court, the creating or continuing of any unlawful obstruction in this act mentioned may be prevented and such obstruction may be caused to be removed by the injunction of any district court exercising jurisdiction in any district in which such obstruction may be threatened or may exist; and proper proceedings in equity to this end may be instituted under the direction of the Attorney-General of the United States.

Legislative History

Notes & Related Subsidiaries

Editorial Notes

References in Text

This act, referred to in text, is act Sept. 19, 1890, ch. 907, 26 Stat. 426. Sections 6 to 9 of the Act are not classified to the Code. For complete classification of this act to the Code, see Tables. Codification Text of section, which was previously omitted from the Code, was restored in view of conflicting court decisions as to whether or not section had been repealed or superseded. See eg. United States v. Wishkah Boom Co., 136 F. 42 (9th Cir. 1905), (appeal dismissed [1906] 202 U.S. 613); United States v. Wilson, 235 F.2d 251 (2d Cir. 1956).

Reference

Citations & Metadata

Citation

33 U.S.C. § 403a

Title 33, Navigation and Navigable Waters

Last Updated

Aug 21, 2026

Release point: 119-102