The waterways and waterbodies listed below are regulated within Los Angeles District as "Traditional Navigable Waters" (TNWs), pursuant to Section 404 of the Clean Water Act, and/or "Navigable Waters," pursuant to Section 10 of the Rivers and Harbors Act.  These jurisdictional waters have been identified as a result of studies conducted by the Corps, or federal court rulings, and do not represent all waters potentially considered to be Section 404 TNWs or Section 10 Navigable Waters.  In particular, all waters subject to the ebb and flow of the tide may be considered Section 10 Navigable Waters and Section 404 Traditional Navigable Waters, beyond those specifically identified below.

CALIFORNIA

^*  Tidal datums used above to identify extent of Corps jurisdiction include Mean High Water (MHW) and Mean Sea Level (MSL).

ARIZONA

¹Section 10 - NAVIGABLE WATERS OF THE UNITED STATES
Navigable waters of the United States are those waters that are subject to the ebb and flow of the tide and/ or are presently used, or have been used in the past, or may be susceptible for use to transport interstate or foreign commerce. A determination of navigability, once made, applies laterally over the entire surface of the waterbody, and is not extinguished by later actions or events which impede or destroy navigable capacity. All waters determined to be navigable waters of the U.S. are also considered to be Traditional Navigable Waters regulated under Section 404 of the Clean Water Act. This excludes Section 10 aquatic resources that are now "fast land"/dry land that are not considered jurisdictional under Section 404.

²Section 404 - TRADITIONAL NAVIGABLE WATERS:
Traditional navigable waters (or waters that are traditionally understood as navigable) refers to all waters which are currently used, were used in the past, or may be susceptible to use in interstate or foreign commerce, including all waters subject to the ebb and flow of the tide.
Territorial seas are defined in CWA section 502(8), 33 U.S.C. 1362(8), as "the belt of the seas measured from the line of ordinary low water along that portion of the coast which is in direct contact with the open sea and the line marking the seaward limit of inland waters, and extending seaward a distance of three miles." The territorial seas establish the seaward limit of "waters of the United States".
Tidal waters and waters subject to the ebb and flow of the tide: The terms tidal waters and waters subject to the ebb and flow of the tide mean those waters that rise and fall in a predictable and measurable rhythm or cycle due to the gravitational pulls of the moon and sun. Tidal waters and waters subject to the ebb and flow of the tide end where the rise and fall of the water surface can no longer be practically measured in a predictable rhythm due to masking by hydrologic, wind, or other effects.