Wetland delineation
A wetland delineation is the field method for finding and marking where a wetland's boundary lies on a piece of land. In Virginia every delineation, isolated wetlands included, must follow the U.S. Army Corps of Engineers' 1987 Wetland Delineation Manual and any regional supplements the Corps has approved.
Virginia requires one method: the Corps' 1987 manual and its approved regional supplements
The 1987 Corps manual is the starting point for every wetland delineation in Virginia. The state's water protection regulation does not leave the method to whoever walks the ground; it names the manual by its technical report number.
Each wetland delineation, including those for isolated wetlands, shall be conducted in accordance with the U.S. Army Corps of Engineers (USACE) "Wetland Delineation Manual, Technical Report Y-87-1, January 1987, Final Report" (Federal Manual) and any regional wetland supplements approved for use by USACE.
Virginia Administrative Code, 9VAC25-210-45
Two details in that sentence matter on a tract here. Isolated wetlands are named outright and delineated the same way as any other. And the regional supplements approved by the Corps travel with the manual, so a delineation follows both. The section was last amended effective November 9, 2022.
The line follows water that stays long enough to change the soil and the plants
A delineation is looking for the edge of something the law has already defined. Virginia's water law and the Corps' regulation at 33 CFR 328.3 share one definition of wetlands, set out with its soil and plant clues in wetlands and what they limit. In the field it comes down to three things.
Water, often and long enough
The definition turns on how often and how long the ground is inundated or saturated, not on whether it is wet on the day someone looks.
The plants that live there
The water has to be enough to support, and under normal circumstances the ground does support, a prevalence of vegetation adapted to saturated soil. EPA calls plants that grow in such conditions hydrophytes.
The soil beneath them
EPA explains that hydric soils and hydrophytes together give clues that a wetland is present.
That is why a delineation is a field exercise and not a glance at a puddle: a low corner that stands wet after a storm is not shown to be a wetland on that evidence alone, and a dry day does not rule one out.
A flagged boundary still needs the Corps and DEQ to say whether it is regulated
A delineation draws a line. It does not, by itself, decide what can happen on either side of it.
Under Clean Water Act section 404 the Corps may permit discharges of dredged or fill material, and Virginia runs its own water protection permit. Whether a delineated area falls under either program is for the Corps and DEQ to determine, and what those permits cover, the farming exemptions included, is the subject of the Land 101 guide on wetlands.
In a sale, the line matters most as subtraction. A buyer working out how much of a tract is actually buildable takes the delineated wet ground out of the plan before pricing the rest. Environmental history on commercial ground is a different study with a different purpose, covered in whether you need a Phase 1 environmental to sell commercial land.
Is there a low, wet corner a buyer wants mapped?
Send the county and a description of the wet ground, and Lowell will read how it sits on the tract and tell you which agencies decide what it means. No cost, no obligation.
Got it. Thank you.
We'll be in touch shortly with an honest read.
Questions about this term
Is a delineated wetland line the same as a flood zone line on a FEMA map?
No. They measure different things. A wetland delineation follows ground saturated often and long enough to support plants adapted to saturated soil, using the 1987 Corps manual. A FEMA special flood hazard area is land with a one percent or greater chance of flooding in any given year. A parcel can have either one, both, or neither, and each is confirmed by a different office.
Is a creek on the tract delineated by the same manual as a wetland?
Not necessarily. Virginia's regulation, 9VAC25-210-45, ties the 1987 Corps manual to wetland delineations. Delineations for surface waters other than wetlands may be conducted under Corps or DEQ policy or guidance, and they must take into consideration the location of an ordinary high water mark, if one is present. Whether that creek is regulated is for the Corps and DEQ to determine.
Where this page's facts come from
Every rule, office and figure above traces to one of these. Rules change; check the office before you act on one.
- 9VAC25-210-45: wetland delineation Virginia Administrative Code
- Va. Code 62.1-44.3: definitions, wetlands Code of Virginia
- 33 CFR 328.3: definitions Code of Federal Regulations
- How wetlands are defined and identified under CWA section 404 U.S. Environmental Protection Agency
- Overview of Clean Water Act section 404 U.S. Environmental Protection Agency