A jurisdictional determination (JD) is the U.S. Army Corps of Engineers’ finding of whether a water or wetland on a site is a “water of the United States” under the Clean Water Act. It is not a permit. It is the yes/no (or which-acres) answer that tells you whether Section 404 even applies.
A delineation maps the wetland line. A JD decides whether that line is federal. People mix those two up, and it costs them time.
Delineation vs JD
A wetland delineation is field work. It uses the Corps manual and the regional supplement: hydrology, hydric soils, hydrophytic plants. The product is a flagged line, a map, acreage, and a report.
A JD is a Corps action. The Corps reviews the report, often walks the flags, and issues a finding. The finding can agree with the map, change the map, or decide that some (or all) of the mapped wetlands are not waters of the United States.
You can have a wetland that is not jurisdictional. After Sackett v. EPA (2023), that is more common than it used to be — especially isolated depressions and wetlands cut off from a relatively permanent water. You can also have a water that is not a three-parameter wetland and still be in 404 (a relatively permanent tributary, a tidal creek). The delineation and the JD answer different questions.
Cypress’s live service page for the field work is Wetland Delineation. This page is the Corps finding that usually comes after it.
Approved vs preliminary
The Corps uses two common products.
Approved JD (AJD). A written determination of what is and is not jurisdictional. It is the document lenders, buyers, and permit reviewers actually want when the question is “does 404 apply to this feature?” AJDs have a stated term (often five years) and can be revisited if the law or the site changes.
Preliminary JD (PJD). You treat the identified aquatic resources as if they were jurisdictional so you can move a permit. It is faster. It is not a finding that they are jurisdictional. If the point of the work is to drop features out of 404, a PJD will not do that.
Which one you ask for depends on the site. A pad next to a mapped pine-flatwoods depression after Sackett is often an AJD question. A pier on a tidal creek where nobody is arguing jurisdiction is often a PJD-and-permit question.
An AJD is what is needed if the site will be sold and the landowner wants to transfer the JD with the site, or if development of the site is not a current project and won’t move into the permitting process until later.
An AJD also takes longer (often substantially longer) for USACE to process.
What the Corps is deciding now
Under Sackett, a wetland is a water of the United States when two things are true:
- The water it connects to is itself a water of the United States (a relatively permanent water, or a traditional navigable water).
- The wetland has a continuous surface connection to that water — as a practical matter, you cannot tell where the water ends and the wetland begins.
EPA and the Corps’ March 2025 field memo reads “continuous surface connection” as abutting or touching. A berm, dike, upland gap, pipe, or culvert is not enough by itself. Isolated wetlands — no abutment to a relatively permanent water — are the features most likely to drop out of federal 404. See What are isolated wetlands? and Sackett v. EPA.
What a JD does not do
It does not replace a state 401 water quality certification, a coastal consistency review, or a Florida ERP. Mississippi, Alabama, Louisiana, and Florida still have their own programs. Losing federal jurisdiction is not the same as “you can fill it.”
It is also not a nationwide or individual permit. If the feature is jurisdictional and you will discharge dredged or fill material, you still need the 404 path. See What Is a 404 Permit?
How we usually start
The useful first step is still a delineation and a straight answer on whether you need an AJD, a PJD, or just a permit. Cypress Environment & Infrastructure does that work from Biloxi, Mobile, and Pensacola, in the Mobile, Vicksburg, Jacksonville and New Orleans Districts. Office hours are Monday–Friday, 9 a.m.–5 p.m.
Questions about how this applies to a Gulf Coast site? Call or write.