US Army Corps of Engineers jurisdiction over wetlands & other waters


The US Army Corps of Engineers (Corps) has jurisdiction to issue permits for discharge into wetlands and streams under Section 10 of the Rivers and Harbors Act and Section 404 of the Clean Water Act (CWA). The figure below shows the jurisdictional boundaries under each of these laws.

A graphic showing the jurisdictional boundaries for Section 10 and Section 404 in tidal and fresh water.

In tidal waters, the Section 10 jurisdiction line is Mean High Water (MHW) and the Section 404 jurisdiction line is the high tide line. The high tide line is the maximum height reached by a rising tide. In fresh water, the Section 10 jurisdiction line is the Ordinary High Water Mark (OHWM). Section 404 jurisdiction includes all areas below OHWM and any tributary rivers, streams, and adjacent wetlands of navigable waters. 

Before using the information on this page, follow the instructions on the Wetland Reconnaissance & Assessment webpage to delineate wetlands, streams, and high tide lines within the project area. 

Section 10

The purpose of the Rivers and Harbors Act is to ensure the free flow of interstate commerce on our aquatic “highways”, or navigable waters. Navigable waters are tidally influenced waters currently or historically used to transport commerce, such as Puget Sound, Lake Washington, and the Columbia River. You will need a Section 10 permit from the Corps when you work on a structure in or over a navigable water of the US.

Check the lists of Navigable Waters in Washington State (pdf 100 kb) on the Streams, Rivers, and Tidal Waters page of the Corps Permit Guidebook to see if the Corps has Section 10 jurisdiction of the waterbody.

Section 404

The purpose of the CWA is to restore and maintain the chemical, physical, and biological integrity of the Nation’s waters, or Waters of the US (WOTUS). You will need a Section 404 permit to discharge dredged or fill material into a WOTUS.

Waters of the US (WOTUS)

On December 23, 2019 the EPA and the Corps finalized a rule to repeal the 2015 Clean Water Rule, taking us back to the Rapanos decision. See the Clean Water Act Jurisdiction following the US Supreme Court's Decision in Rapanos v. United States & Carabell v. United States: Summary of key facts to determine if there are jurisdictional waters in your project area.

See the EPA WOTUS Rulemaking website for current updates to WOTUS policy decisions and more information on the Rapanos decision and court case. The WSDOT Wetlands Program will share more information as it becomes available on how to implement current WOTUS rules, including ditch assessments, on WSDOT projects.


The CWA says the Corps has jurisdiction over discharges into WOTUS. Discharge means placement of material, excluding structures. Examples of discharge include:

  • Placement of fill (rock, dirt, and sandbags)
  • Mechanized land clearing
  • Grading
  • Excavation (including ditching in some instances)
  • Piling (if a form is placed in a WOTUS and wet concrete is poured into the form, the work would be regulated as fill. A pre-made concrete piling installed is not fill, it is a structure.)

Clean excavation is not considered discharge as long as there is only incidental fallback. Incidental fallback is the minor amount of material that may fall from the sides of a bucket excavator during excavation.

Ditches and maintenance activities or emergency repairs

Highway maintenance activities or emergency repairs occurring in WOTUS (e.g. removing sediment from ditches with wetland characteristics to restore back to the original profile) may be exempt from needing Corps permits under Section 404 of the CWA, 33 CFR 323.4. See the Exemptions from Section 404 review webpage for more information on Section 404 Corps exempted activities.

    Getting a jurisdictional determination from the Corps

    If you think the Corps has jurisdiction, follow the instructions on the Section 404 & 10 Nationwide Permits webpage to apply for a permit from the Corps. The Corps will make a jurisdictional determination using the application documents.

    If you don’t think the Corps has jurisdiction, submit a Request for Jurisdictional Determination form (pdf 82 kb) and a wetland delineation to the Corps liaisons. Find instructions for preparing a wetland delineation on the Wetland reconnaissance & assessment webpage.

    Find information on the Corps’ Jurisdictional Determination process and approvals on their Approved Jurisdictional Determinations website.