33 CFR § 321.2 - Definitions.

---
identifier: "/us/cfr/t33/s321.2"
source: "ecfr"
legal_status: "authoritative_unofficial"
title: "33 CFR § 321.2 - Definitions."
title_number: 33
title_name: "Navigation and Navigable Waters"
section_number: "321.2"
section_name: "Definitions."
chapter_name: "CORPS OF ENGINEERS, DEPARTMENT OF THE ARMY, DEPARTMENT OF DEFENSE"
part_number: "321"
part_name: "PERMITS FOR DAMS AND DIKES IN NAVIGABLE WATERS OF THE UNITED STATES"
positive_law: false
currency: "2026-03-24"
last_updated: "2026-03-24"
format_version: "1.1.0"
generator: "[email protected]"
authority: "33 U.S.C. 401."
regulatory_source: "51 FR 41227, Nov. 13, 1986, unless otherwise noted."
cfr_part: "321"
---


# 321.2 Definitions.

For the purpose of this regulation, the following terms are defined:

(a) The term *navigable waters of the United States* means those waters of the United States that are subject to the ebb and flow of the tide shoreward to the mean high water mark and/or are presently used, or have been used in the past, or may be susceptible to use to transport interstate or foreign commerce. See 33 CFR part 329 for a more complete definition of this term.

(b) The term *dike or dam* means, for the purposes of section 9, any impoundment structure that completely spans a navigable water of the United States and that may obstruct interstate waterborne commerce. The term does not include a weir. Weirs are regulated pursuant to section 10 of the Rivers and Harbors Act of 1899. (See 33 CFR part 322.)